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11.  Archaic Homo

Amanda Wolcott Paskey, M.A., Cosumnes River College

AnnMarie Beasley Cisneros, M.A., American River College

Learning Objectives

Describe the unique anatomical and cultural characteristics of archaic

Homo sapiens in contrast to other hominins.

Articulate how archaic Homo sapiens fossils �t into anatomical evolu-

tionary trends including brain size development, as well as cultural in-

novations and distribution throughout the Old World.

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Figure 11.1 Popular perceptions of human ancestors at the transition to modern Homo sapiens often take the form of the stereotypical, and inaccurate, “caveman.”

Explain how shifting environmental conditions required �exibility of

adaptations, both anatomically and culturally, for hominin survival and

the potential consequences of a high degree of specialization.

Recognize that while archaic Homo sapiens share similarities, they are

characterized by signi�cant regional variation and local adaptation.

Detail the increased complexity and debates surrounding archaic

Homo sapiens’ classi�cation in light of transitional species, species ad-

mixture, etc.

BREAKING THE STIGMA OF THE “CAVEMAN”

What do you think of when you hear the word “caveman”?

Perhaps you imagine a character from a �lm such as The

Croods, Tarzan, or Encino Man or from the cartoon The Flint-

stones. Maybe you picture the tennis-playing, therapy-going

hairy Neanderthals from Geico Insurance commercials. Or

perhaps you imagine comic characters from “The Far Side” or

“B.C.” comics. Whichever you picture, the character in your

mind is likely stooped over with a heavy brow, tangled long

locks and other body hair, and clothed in animal skins, if any-

thing. They might be holding a club with a confused look on

their face, standing at the entrance to a cave or dragging an

animal carcass to a �re for their next meal (see Figure 11.1).

You might have even signed up to take this course because of

what you knew—or expected to learn—about “cavemen.”

These images have long been the stigma and expectation about our ancestors at the

transition to modern Homo sapiens. Tracing back to works as early as Linnaeus, sci-

entists once propagated and advanced this imagery, creating a clear picture in the

minds of early scholars that informed the general public, even through today, that

archaic Homo sapiens, “cavemen,” were somehow distinctly different and much less

intelligent than we are now. Unfortunately, this view is incorrect, overly simplistic,

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and misleading. Understanding what archaic Homo sapiens were actually like re-

quires a much more complex and nuanced picture, one that continues to be under-

stood with greater clarity as current research uncovers the lives of our not-too-dis-

tant (and not-too-different) ancestors.

The �rst characterizations of archaic Homo sapiens were formed from limited fossil

evidence in a time when ethnocentric and species-centric perspectives (

anthropocentrism) were more extensively accepted and entrenched in both society

and science. Today, scientists are working from a more complete fossil record from

three continents (Africa, Asia, and Europe) and even genetic evidence that informs

their analyses and conclusions. The existence of archaic Homo sapiens mark an ex-

citing point in our lineage—a point at which many modern traits had emerged and

key re�nements were on the horizon. Anatomically, we today are not that much dif-

ferent from archaic Homo sapiens.

This chapter will examine the environment with which archaic Homo sapiens had to

contend, one that shaped their, and our, ultimate development. It will also examine

the key anatomical traits that de�ne this group of fossils (including the infamous

subgroup known as Neanderthals), cultural innovations that aided their adaptation

to the changing environment, and their geographic distribution and regional varia-

tions. Additionally, it will consider areas of exciting new research that suggest even

greater nuance and complexity during this time period. Our understanding of this

species and our evolution is complex and exciting and could become even more so

as new data is uncovered.

THE CHANGING ENVIRONMENT

While modern climate change is of critical concern today due to its cause (human

activity) and pace (unprecedentedly rapid), the existence of global climate change

itself is not a recent phenomenon. The climate across the globe has changed, drasti-

cally at times, over the course of Earth’s existence. The Pleistocene epoch—between

1.8 million years ago (mya) and 11,000 years ago (kya); illustrated in Figure 7.7—was a

time of great climatic upheaval. The Middle Pleistocene, roughly between 780 kya

and 125 kya, is the time period in which archaic Homo sapiens appear in the fossil

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record—a time that witnessed some of the most drastic climatic changes that have

been seen in human existence. During this time period, there were 15 major and 50

minor glacial events in Europe alone!

What exactly is a glaciation? When scientists talk about glacial events, they are re-

ferring to the climate being in an ice age. This means that the ocean levels were

much lower than today, as much of the earth’s water was tied up in large glaciers or

ice sheets. Additionally, the average temperature would have been much cooler,

which would have better supported an Arctic or tundra-adapted plant-and-animal

ecosystem in northern latitudes. The most interesting and relevant features of Mid-

dle Pleistocene glacial events are the sheer number of them and their repeated

bouts—this era alternated between glacial periods and warmer periods, known as

interglacials. In other words, the world wasn’t in an ice age the whole time.

How have scientists determined how many glaciations there were during the Middle

Pleistocene and how severe they were? Several lines of evidence help inform our un-

derstanding of past climates. One important source is the study of oxygen isotopes

preserved in the shells of marine invertebrates called foraminifera. Foraminifera in-

corporate oxygen from seawater during their life. When they die, foraminifera shells

fall to the ocean �oor and can be preserved as microscopic fossils that are part of

the sediment, which can later be sampled and studied in sediment cores. Studying

these cores has revealed that the oxygen isotope present varies depending on Earth

temperatures at the time the foraminifera were alive. During glacial periods, seawa-

ter is cooler and one oxygen isotope— O—is in higher concentrations in seawater

(and, as a result, in foraminifera shells) because it is heavier. In contrast, water with

the oxygen isotope O is lighter and therefore evaporates �rst, becomes part of

precipitate (such as snow), and eventually becomes trapped in glaciers. During in-

terglacials, O returns to the ocean in water runoff, resulting in higher ocean and

foraminifera concentrations of this oxygen isotope. Recent research with ice cores

further con�rms the length and severity of glacial periods using similar techniques.

The Pleistocene is characterized by shifts in Earth’s temperatures and their impact

on plant and animal life. The Middle Pleistocene was an even more intense period of

�uctuation with frequent and severe glacial and interglacial episodes recorded in

marine isotopes, among other data points. You can see the dramatic and increasing

�uctuations in temperature, recorded through foraminifera, in the chart (Figure

18

16

16

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11.2). The distance between lows and highs demonstrates the severity of tempera-

ture shift. Much as the Richter scale represents more intense earthquakes with

more dramatic peaks, so too does this chart, which uses dramatic peaks to demon-

strate intense temperature swings.

Figure 11.2 The Geologic Timescale and corresponding temperature shifts. Note the wide and rapid shifts during the Pleistocene (the second box from the right). More dramatic �uctuations depict greater severity of temperature shift.

Glacial periods are de�ned by Earth’s average temperature being lower. Worldwide,

temperatures are reduced, with cold areas becoming even colder. The water cycle

experiences limited runoff as water evaporates from the seas, precipitates (often as

snow and ice), and accumulates in glaciers with little precipitation melting as runoff.

Over time, continued evaporation with little runoff results in the accumulation of

snowpacks and glaciers at the expense of sea level, which is lowered. In simple

terms, the water that is normally in the sea is now tied up on land as ice. Huge por-

tions of the landscape may have become inaccessible during glacial events due to

the formation of glaciers and massive ice sheets. In Europe, the Scandinavian conti-

nental glacier covered what is today Ireland, England, Sweden, Norway, Denmark,

and some of continental Europe. Plant and animal communities shifted to lower lati-

tudes along the periphery of ice sheets. Additionally, some new land was opened

during glacials. Evaporation with little runoff reduced sea levels by as much as al-

most 150 meters, shifting coastlines outward by in some instances as much as al-

most 100 kilometers. Additionally, land became exposed that connected what were

previously unconnected continents such as Africa at the Gulf of Aden into Yemen.

Glacial periods also affected equatorial regions and other regions that are today

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thought of as warmer or at least more temperate parts of the globe, including Africa.

While these areas were not covered with glaciers, the impact of increased global

glaciation resulted in lower sea levels and expanded coastlines. Cooler temperatures

were accompanied by the drying of the climate, which caused signi�cantly reduced

rainfall, increased aridity, and the expansion of deserts. It is an interesting question

to consider whether the same plants and animals that lived in these regions prior to

the ice ages would be able to survive and thrive in this new climate? Plant and ani-

mal communities shifted in response to the changing climate, whenever possible.

Rather than a single selective force, the Middle Pleistocene was marked by periods

of �uctuation, not just cold periods. Interglacials interrupted glaciations, reversing

trends in sea level, coastline, temperature, precipitation, and aridity, as well as

glacier size and location. Interglacials are marked by increased rainfall and a higher

temperature, which causes built-up ice in glaciers to melt. Interglacials are marked

by glacial retreat, which is the shrinking of glaciers and the movement of the

glaciers back toward the poles, as we’ve seen in our lifetime. During interglacials, sea

levels increase, �ooding some previously exposed coastlines and continental con-

nections. In addition, plant and animal communities shift accordingly, often �nding

more temperate climates to the north and less arid and more humid climates in the

tropics.

Scientists have found that at one site, the Olorgesailie region in southern Kenya, a

single location was at various times in the Middle Pleistocene a deep lake, a

drought-dried lakebed, small streams, and a grassland. While various animal species

would have moved in and out of the area as the climate shifted, some animal species

went extinct, and new, often related, species took up residence. The trend, scientists

noted, was that animals with more specialized features went extinct and animals

with more generalized features, such as animals we see today, survived in this

changing climatic time period. For example, a zebra with specialized teeth for eating

grass was ultimately replaced by a zebra that could eat grass and other types of veg-

etation. The exclusively terrestrial fossil baboon Therapithecus oswaldi was replaced

by Papio anubis, the more �exible locomotor baboon that exists in the region today.

If this small, localized example shows such a dramatic change in terms of the envi-

ronment and the plant and animal biocommunities, what would have been the im-

pact on humans?

There is no way humans could have escaped the effects of Middle Pleistocene cli-

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mate change, no matter what region of the world they were living in. As noted ear-

lier, and as evidenced by what was seen in the other biotic communities, humans

would have faced changing food sources as previous sources of food may have gone

extinct or moved to a different latitude. Depending on where they were living, fresh

water may have been limited. Durial glacials, lower sea levels would have given hu-

mans more land to live on, while the interglacials would have reduced the available

land through the increase in rainfall and associated sea level rise. Dry land connec-

tions between the continents would have made movement from one continent to

another by foot easier at times than today, although these passageways were not

consistently available through the Middle Pleistocene due to the glacial/interglacial

cycle. Finally, as evidenced by the study at the Olorgesailie region in Kenya, during

the Middle Pleistocene animal species that were overly specialized to one particular

type of environment were less likely to survive when compared to their more gener-

alized counterparts. Evidence suggests that this same pattern may have held true for

archaic Homo sapiens, in terms of their ability to survive this dramatic period of cli-

mate change.

DEFINING CHARACTERISTICS OF ARCHAIC HOMO SAPIENS

Archaic Homo sapiens share our species name but are distinguished by the term “ar-

chaic” as a way of recognizing both the long period of time between their appear-

ance and ours, as well as the way in which human traits have continued to evolve

over time—making archaic Homo sapiens look slightly different from us today, de-

spite technically being considered the same species. Living throughout the Old

World during the Middle Pleistocene, archaic Homo sapiens are considered, in many

ways, transitional between Homo erectus and modern Homo sapiens (see Figure 11.3).

All archaic Homo sapiens share the de�ning trait of an increased brain size—speci�-

cally a brain of at least 1,100 cc and averaging 1,200 cc—but are also characterized by

signi�cant regional and temporal (time) variations. Because of these variations, sci-

entists disagree on whether these fossils represent a single, variable species or mul-

tiple, closely related species (sometimes called Homo antecessor, Homo heidelbergen-

sis, Homo georgicus, Homo neanderthalensis, and Homo rhodesiensis). For simplicity

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we are going to lump them all together under the heading of archaic Homo sapiens

and discuss them as a unit, with the exception of a particularly unique and well-

known population living in Europe and West Asia known as the Neanderthals, which

we will examine separately.

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Trait Homo erectus Archaic Homo sapiens

Anatomically

Modern Homo

sapiens

Aver-

age

Brain

Size

900 cc 1,200 cc (1,500 cc when in-

cluding Neanderthals) 1,400 cc

Skull

Shape

Long and low

Angular Intermediate

Short and

high

Globular

Fore-

head Absent Emerging Present

Nasal

Re-

gion

Projecting nasal

bones (bridge of

the nose), no

midfacial

prognathism

Wider nasal aperture and

midfacial prognathism

Narrower

nasal aper-

ture, no mid-

facial

prognathism

Chin Absent Absent Present

Other

Facial

Fea-

tures

Large brow ridge

and large project-

ing face

Intermediate

Small brow

ridge and

retracted

face

Other

Skull

Fea-

tures

Nuchal torus,

sagittal keel,

thick cranial

bone

Projecting occipital bone,

often called occipital bun in

Neanderthals; intermediate

thickness of cranial bone

Small bump

on rear of

skull, if any-

thing; thin

cranial bone

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Den-

tition

Large teeth, es-

pecially front

teeth

Slightly smaller teeth; front

teeth still large;

retromolar gap in

Neanderthals

Smaller teeth

Postc

ranial

Fea-

tures

Robust bones of

skeleton Robust bones of skeleton

More gracile

bones of

skeleton

Figure 11.3 A comparison of Homo erectus, archaic Homo sapiens, and anatomically

modern Homo sapiens. This table compares key traits of the crania and postcrania

that distinguish these three hominins.

When comparing Homo erectus, archaic Homo sapiens, and anatomically modern

Homo sapiens across several anatomical features, one can see quite clearly that ar-

chaic Homo sapiens are intermediate in their physical form. This follows the trends

�rst seen in Homo erectus for some features and in other features having early, less

developed forms of traits more clearly seen in modern Homo sapiens. For example,

archaic Homo sapiens trended toward less angular and higher skulls than Homo

erectus but had skulls notably not as short and globular in shape and with a less de-

veloped forehead than anatomically modern Homo sapiens. archaic Homo sapiens

had smaller brow ridges and a less-projecting face than Homo erectus and slightly

smaller teeth, although incisors and canines were often about as large as that of

Homo erectus. Archaic Homo sapiens also had a wider nasal aperture, or opening for

the nose, as well as a forward-projecting midfacial region, known as

midfacial prognathism. The occipital bone often projected and the cranial bone was

of intermediate thickness, somewhat reduced from Homo erectus but not nearly as

thin as that of anatomically modern Homo sapiens. The postcrania remained fairly

robust, as well. To identify a set of features that is unique to the group archaic Homo

sapiens is a challenging task, due to both individual variation—these developments

were not all present to the same degree in all individuals—and the transitional na-

ture of their features. Neanderthals will be the exception, as they have several

clearly unique traits that make them notably different from modern Homo sapiens as

well as their closely related archaic cousins.

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Figure 11.4 “Broken Hill Man” archaic Homo sapiens cranium found at Kabwe in Zambia. One of several individuals found at this site, this cranium re�ects common traits associated with archaic Homo sapiens in Africa including a large brain, taller cranium, and many Homo erectus-like features such as massive brow ridges, a large face, and thick cranial bones.

Figure 11.5 Atapuerca 5 archaic Homo sapiens found in northern Spain. One of many fossils found at this site, this fossil is representative of traits seen in archaic Homo sapiens in Europe including thick a cranial bone, enlarged cranial capacity, intermediate cranial height, and a more rounded cranium, as well as increased midfacial prognathism.

The one thing that is clear about archaic Homo sapi-

ens is that regional variation, �rst seen in the differ-

ent Homo erectus specimens across Asia and Africa,

is clearly present and even more pronounced. While

the general features of archaic Homo sapiens, identi-

�ed earlier, are present in the fossils of this time pe-

riod, there are signi�cant regional differences. The

majority of this regional variation lies in the degree

to which fossils have features more closely aligned

with Homo erectus or with anatomically modern

Homo sapiens.

To illustrate this point,

we will examine three

exemplary specimens,

one from each of the

three continents on

which archaic Homo

sapiens lived. In Africa,

“Broken Hill Man,” one of several individuals found in

the Kabwe lead mine in Zambia, had a large brain

(1,300 cc) and taller cranium as well as many Homo

erectus-like skull features, including massive brow

ridges, a large face, and thick cranial bones (Figure

11.4). Conditions for preservation in Asia during the

Middle Pleistocene were not as conducive to the fos-

silization of complete crania; however, many archaic

Homo sapiens skullcaps have been found. One partial

crania from Dali, China, is representative of archaic

Homo sapiens in Asia, including large and robust fea-

tures with heavy brow ridges, akin to what is seen in Homo erectus, and a large cra-

nial capacity intermediate between Homo erectus and anatomically modern Homo

sapiens. Across Europe, many near-complete archaic Homo sapiens crania have been

discovered, including one, part of an almost-complete skeleton, found in northern

Spain at Atapuerca. Atapuerca 5 (Figure 11.5) has thick cranial bone, an enlarged cra-

nial capacity, intermediate cranial height, and a more rounded cranium than seen

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previously. Additionally, Atapuerca 5 demonstrates features that foreshadow Nean-

derthals, including increased midfacial prognathism. After examining some of the

fossils, the transitional nature of archaic Homo sapiens is clear—their features place

them squarely between Homo erectus and modern Homo sapiens.

Due to the transitional nature of archaic Homo sapiens, identifying the time period

they are associated with is problematic and complex. Generally, it is agreed upon

that archaic Homo sapiens lived between 600,000 and 200,000 years ago. But re-

gionally this varies with considerable overlap between Homo erectus on the early

end of the spectrum and modern Homo sapiens and Neanderthals on the latter end.

The earliest-known archaic Homo sapiens fossils tentatively date to about 600,000

years ago in Africa, whereas archaic Homo sapiens fossils in Asia appear around

300,000 years ago and in Europe around 350,000 years ago (and potentially as early

as 600,000 years ago). The end point of archaic Homo sapiens is also problematic

since it largely depends upon when the next subspecies of Homo sapiens appears

and the classi�cation of highly intermediate specimens. For example, in Africa, the

end of archaic Homo sapiens is met with the appearance of modern Homo sapiens,

while in Europe it is the appearance of Neanderthals that is traditionally seen as the

end of archaic Homo sapiens.

Archaic Homo sapiens mark an important chapter in the human lineage, bridging

more ancestral forms, such as Homo erectus, with modern Homo sapiens. During this

period of climatic transition and �uctuation, archaic Homo sapiens mirror the chal-

lenges of their environments. Showing increasing regional variation due to the need

for local adaptation, there is no single archetype for this group but, rather, multiple

variations; their transitional nature is one of their key de�ning characteristics.

NEANDERTHALS

One particularly well-known population of archaic Homo sapiens are the Nean-

derthals, named after the site where they were �rst discovered in the Neander Val-

ley, or “thal” in German, located near Dusseldorf, Germany. Popularly known as the

stereotypical “cavemen” examined at the outset of this chapter, recent research is

upending long-held beliefs about this group of archaics. As mentioned in the intro-

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duction, Neanderthals have long been thought to be dumb brutes who were, behav-

iorally speaking, not much different from apes. However, today, scientists agree that

Neanderthal behavior was increasingly complex and nuanced, far beyond what was

exhibited by even other archaic Homo sapiens discussed throughout this chapter.

We implore you to forget the image of the iconic caveman and have an open mind

when exploring the fossil evidence of the Neanderthals.

It is important to understand why Neanderthals are typically separated from other

archaic Homo sapiens. Unlike the rest of archaic Homo sapiens, Neanderthals are

easily de�ned and identi�ed in many ways. There is a clear geographic boundary of

where Neanderthals lived: western Europe, the Middle East, and western Asia. The

time period for when Neanderthals lived is widely accepted as between 150,000 and

35,000 years ago. Additionally, Neanderthals have a unique and distinct cluster of

physical characteristics. While a few aspects of Neanderthals are less clear cut and

are shared among some archaic Homo sapiens, such as the types of tools they cre-

ated and used, most attributes of Neanderthals, both anatomically and behaviorally,

are unique to them.

As mentioned previously, the geographic distribution of Neanderthals is very spe-

ci�c. Neanderthal fossils, thus far, have been found across a narrow latitude of west-

ern Europe, the Middle East, and western Asia. No Neanderthal fossils have ever

been discovered outside of this area, including Africa. This is a bit curious, as other

archaics seem to have adapted in Africa and then migrated elsewhere, but Nean-

derthals’ regional association makes sense in light of the environment to which they

were best adapted. While Neanderthals lived in different ecosystems, including tem-

perate environments, they were very well adapted to extreme cold weather and

their geographic distribution includes what would have been some of the coldest

habitable locations at the time of their existence.

Neanderthals lived during some of the coldest times during the last Ice Age and at

far northern latitudes. This means Neanderthals were living very close to the glacial

edge, and not in a more temperate region of the globe, like some of their archaic

Homo sapiens relatives. Their range likely expanded and contracted along with Eu-

ropean glacial events, moving into the Middle East during glacial events when Eu-

rope became even cooler, and when the animals they hunted would have moved for

the same reason. During interglacials, when Europe warmed a bit, Neanderthals and

their prey would have been able to move back into Western Europe.

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Many of the Neanderthals’ de�ning physical features are more extreme and robust

versions of traits seen in other archaic Homo sapiens, clustered in this single popu-

lation (Figure 11.6). Brain size is one of the Neanderthal features that continues to

follow the same patterns as seen with other archaic Homo sapiens, namely an en-

largement of the cranial capacity. The average Neanderthal brain size is around

1,500 cc, and the range for Neanderthal brains can extend to upwards of 1,700 cc.

The majority of the increase in the brain occurs in the occipital region, or the back

part of the brain, resulting in a skull that has a large cranial capacity with a distinctly

long and low shape that is slightly wider than previous forms at far back of the skull.

Modern humans have a brain size comparable to that of Neanderthals; however, our

brain expansion occurred in the frontal region of the brain, not the back, as in Nean-

derthal brains. This difference is also the main reason why Neanderthals lack the

vertical forehead that modern humans possess. They simply did not need an en-

larged forehead, because their brain expansion occurred in the rear of their brain.

Due to cranial expansion, the back of the Neanderthal skull is less angular (as com-

pared to Homo erectus) and is more rounded, a feature similar to that of modern

Homo sapiens.

Another feature that continues the trend noted in previous hominins is the enlarge-

ment of the nasal region, or the nose. Neanderthal noses are large and have a wide

nasal aperture, which is the opening for the nose. While the nose is only made up of

two bones, the nasals, the true size of the nose can be determined by looking at

other facial features, including the nasal aperture, and the angle of the nasal and

maxillary, or facial bones. In Neanderthals, these indicate a large, forward-projecting

nose that appears to be pulled forward away from the rest of the face. This feature is

further emphasized by the backward-sloping nature of the cheekbones, or the zygo-

matic arches. The unique shape and size of the Neanderthal nose is often character-

ized by the term midfacial prognathism—a jutting out of the middle portion of the

face, or nose. This is in sharp contrast to the prognathism exhibited by other ho-

minins, who exhibited prognathism, or the jutting out, of their jaws.

The teeth of the Neanderthals follow a similar pattern seen in the archaic Homo

sapiens, which is an overall reduction in size, especially as compared to the ex-

tremely large teeth seen in the genus Australopithecus. However, while the teeth

have continued to reduce, the jaw size does not keep pace, leaving Neanderthals Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

with an interesting situation. Their jaw is oversized for their teeth, leaving a gap be-

tween their �nal molar and the end of their jaw. This gap is called a retromolar gap.

The projecting occipital bone present in other archaic Homo sapiens is also more

prominent in Neanderthals, extending the trend found in archaics. Among Nean-

derthals, this projection of bone is easily identi�ed by its bun shape on the back of

the skull and is known as an occipital bun. This projection appears quite similar to a

dinner roll in size and shape. Its purpose, if any, remains unknown.

Continuing the archaic Homo sapiens trend, Neanderthal brow ridges are prominent

but somewhat smaller in size than those of Homo erectus and earlier archaic Homo

sapiens. In Neanderthals, the brow ridges are also often slightly less arched than

those of other archaic Homo sapiens.

In addition to extending traits present in archaic Homo sapiens, Neanderthals pos-

sess several distinct traits. Neanderthal infraorbital foramina, the holes in the max-

illae or cheek bones through which blood vessels pass, are notably enlarged com-

pared to other hominins. The Neanderthal postcrania are also unique in that they

demonstrate increased robusticity in terms of the thickness of bones and body pro-

portions that show a barrel-shaped chest and short, stocky limbs, as well as in-

creased musculature. These body portions are seen across the spectrum of Nean-

derthals—in men, women, and children.

Many of the unique traits that Neanderthals possess can be attributed to adaptation

to the extreme cold environments in which they often lived. Together explained as

cold adaptations, these traits are thought to be a response to the cold, dry environ-

ments in which Neanderthals lived and which certainly exerted strong selective

forces. For example, Bergmann’s and Allen’s Rules dictate that an increased body

mass and short, stocky limbs are common in animals that live in cold conditions. Ne-

anderthals match the predictions of Bergmann’s and Allen’s Rules perfectly. In addi-

tion, the Neanderthal skull also exhibits adaptations to the cold. Neanderthals’ large

infraorbital foramina allow for larger blood vessels, increasing the volume of blood

that is found closest to the skin, which helps to keep the skin warmer. The midfacial

prognathism present in Neanderthals indicates that Neanderthals would have had a

large nose. This enlarged nose may also have been bene�cial to have in cold weather

due to longer nasal passages and mucus membranes for cold air to travel through

before reaching the lungs. It is very uncomfortable and challenging to breathe and

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exert oneself in exceptionally cold, dry air. The more time the air spends in the mu-

cus membranes, the warmer and more moist the air will be before it reaches the

lungs. The Neanderthals’ larger nose has long been thought to have acted as a hu-

midi�er, easing physical exertion in their climate, although research on this particu-

lar trait continues to be studied and debated.

Distinct Neanderthal Anatomical Features

Brain Size 1,500 cc average

Skull Shape Long and low

Brow Ridge Size Large

Nose Size Large, with midfacial prognathism

Dentition Reduced, but large jaw size, creating retromolar

gap

Occipital Region Enlarged occipital region, occipital bun

Other Unique Cranial

Features Large infraorbital foramina

Postcranial Features Short and stocky body, increased musculature,

barrel-shaped chest

Figure 11.6 Neanderthal distinguishing features. This table outlines key features associ-

ated with Neanderthals.

In summary, Neanderthal characteristics are a distinct cluster of features, some of

which were apparent in previous hominins and others that were unique. Addition-

ally, it is clear that Neanderthals were specially adapted to a particular environment

—a very cold one. A classic example of a Neanderthal with all of the characteristics

mentioned above is the La Ferrassie 1 Neanderthal, from France. The skeleton is near

complete, which is not necessarily unique among Neanderthal fossils as many par-

tially complete remains have been found, but it does provide us with a lot of infor-

mation. The La Ferrassie 1 Neanderthal, who was male, had a brain size of around

1640cc and had an extremely large nose and infraorbital foramina. Additionally, the Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

Figure 11.7 La Ferrassie 1 Neanderthal is representative of many classic Neanderthal features including a large brain, large nose, large infraorbital foramina, large brow ridges, and robust postcrania.

brow ridges are marked in size, and the overall skeleton is

robust (Figure 11.7).

What are the bene�ts or the potential challenges Nean-

derthals could have faced for being highly specialized to

one particular environment, when we know their environ-

ment and climate were in �ux?

Neanderthal Culture and Lifeways

One key Neanderthal adaptation was their cultural innova-

tions. Cultural innovation is a key way that hominins adapt

to their environment. As you recall, the culture of Homo

erectus was marked by the development of a bifacial tool,

the Acheulean handaxe, which allowed them differential

access to meat on animal carcasses when compared to

their predecessors. For Homo erectus, the Acheulean han-

daxe allowed more ef�cient removal of meat and possibly

calculated scavenging. The increase in their body and brain

size, along with their more effective tools, allowed them to track predators and

snatch their kills sometimes even before the predators themselves had even fed.

Acheulean tools represent a signi�cant increase in complexity over Oldowan tools,

as they required more time, effort, and skill to shape. Acheulean handaxes were not

only worked on two sides, they shared a common shape, which required fore-

thought and advanced planning by their makers. Homo erectus would have had a

mental template for the desired outcome and, with practice, these tools were likely

made quite quickly and could have been made by most individuals. While these tools

were a signi�cant step forward in tool production, they were not intended to be

kept. Homo erectus discarded the tools after use and treated them as a disposable

item.

In contrast, Neanderthal tools mark a signi�cant innovation both in tool-making

technique and their use. Known as Mousterian tools, after the Le Moustier site in

southwest France, the Neanderthal’s toolkit was truly that—a set of tools with spe-

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ci�c applications and unique forms for each desired purpose. Mousterian tools were

signi�cantly smaller, thinner, and lighter than Acheulean handaxes and formed a

true toolkit. The materials used for Mousterian tools were of higher quality, which

allowed for both more precise toolmaking and tool reworking when the tools broke

or dulled after frequent reuse. The use of higher-quality materials is also indicative

of required forethought and planning to acquire them for tool manufacture. It is

noteworthy that the Neanderthals, unlike Homo erectus, saved and reused their

tools, rather than making new ones each time a tool was needed.

Figure 11.8 The Levallois technique is used to create Mousterian tools. The multistep process involves preparing the core, or raw material, in a speci�c way that will yield �akes that are roughly uniform in dimension. The �akes are then turned into individual tools.

Mousterian tools are constructed in a very unique manner, utilizing the

Levallois technique (Figure 11.8), named after the �rst �nds of tools made with this

technique, which were discovered in the Levallois-Perret suburb of Paris, France.

The Levallois technique is a multistep process that requires preparing the core, or

raw material, in a speci�c way that will yield �akes that are roughly uniform in di-

mension. The �akes are then turned into individual tools. The preparation of the

core is akin to peeling a potato or carrot with a vegetable peeler—when peeling veg-

etables, you want to remove the skin in long, regular strokes, so that you are taking

off the same amount of the vegetable all the way around. In the same way, the Leval-

lois technique requires removing all edges of the cortex, or outside surface of the

raw material, in a circle before removing the lid. The �akes, which will eventually be

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turned into the individual tools, can then be removed from the core. The potential

yield of tools from one core would be many, as seen in Figure 11.9, compared to all

previous tool-making processes, in which one core yielded a single tool.

Figure 11.9 Levallois core and �akes for tool production. Using this technique, one core is used to produce many �akes, each of which can be turned into a tool.

Neanderthal tools were used for a variety of purposes. They would have constructed

a tool for each speci�c task they needed to complete, such as cutting, butchering,

woodworking or antler working, and hide working. Additionally, because the Mous-

terian tools were lighter than previous stone tools, Neanderthals could haft, or at-

tach the tool onto a handle, as the stone would not have been too heavy. Nean-

derthals attached small stone blades onto short wood or antler handles to make

knives or other small weapons, as well as attached larger blades onto longer shafts

to make spears. New research examining tar-covered stones and black lumps at sev-

eral Neanderthal sites in Europe suggests that Neanderthals may have been making

tar by distilling it from birch tree bark, which could have been used to glue the stone

tool onto its handle. If Neanderthals were, in fact, manufacturing tar to act as glue,

this would predate modern humans in Africa making tree resin or similar adhesives

by nearly 100,000 years! While research on speci�c applications continues, from just

this brief discussion, it should be clear that Neanderthal tool manufacturing was

much more complex than previous tool-making efforts, requiring skill and patience

to carry out.

With their more sophisticated suite of tools, Neanderthals were better armed for

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hunting than previous hominins and had very robust bodies with larger muscles.

The animal remains in Neanderthal sites show that unlike earlier archaic Homo sapi-

ens, Neanderthals were very effective hunters who were able to kill their own prey,

rather than relying on scavenging. Oftentimes, this included very large animals like

deer, horses, and bovids (relatives of the cow). In fact, isotopes from Neanderthal

bones show that meat was a primary and signi�cant component of their diet, similar

to that seen in carnivores like wolves (Bocherens et al. 1999). Of course, Nean-

derthals’ diet varied according to the speci�c environment in which they lived, but

according to Christoph Wiẞin and colleagues (2015), meat comprised up to 80% of

their diet.

Though more sophisticated than the tools of earlier hominins, the Neanderthal

spear was not the kind of weapon that would have been thrown; rather, it would

have been used in a jabbing fashion (Churchill 1998; Kortlandt 2002). This may have

required Neanderthals to hunt in groups rather than individually, and it almost cer-

tainly meant that they would have had to approach their prey quite closely. Remem-

ber, the animals living with Neanderthals were very large-bodied due to their adap-

tations to cold weather. In addition to large bovids, prey included ibex, seals, rabbits,

and pigeons. Though red meat was a critical component of the Neanderthal diet, ev-

idence shows that at times they also ate limpets, mussels, and pine nuts. Tartar ex-

amined from Neanderthal teeth in Iraq and Belgium reveal that plant material in-

cluding wheat, barley, date palms, and tubers were also eaten by Neanderthals and

were cooked to make them palatable.

While the new, close-range style of hunting used by Neanderthals was effective, it

also had some major consequences. Many Neanderthal skeletons have been found

with signi�cant injuries, which could have caused paralysis or severely limited their

mobility. Many of the injuries are to the head, neck, or upper-body. Thomas Berger

and Erik Trinkaus (1995) conducted a statistical comparative analysis of Neanderthal

injuries compared to those recorded in modern day workers’ compensation reports

and found that the closest match was between Neanderthal injuries and those of

rodeo workers. Rodeo professionals have a high rate of head and neck injuries that

are similar to the Neanderthals’ injuries. What do Neanderthals and rodeo workers

have in common? They were both getting very close to large, strong animals, and at

times their encounters might have gone awry.

The extensive injuries sustained by Neanderthals are evident in many fossil remains.

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Shanidar 1 (Figure 11.10), an adult male found at the Shanidar site in northern Iraq

and dating to 45,000 ya, has a lifetime of injuries recorded in his bones. Shanidar 1

sustained—and healed from—an injury to his face that would have likely caused

blindness. His lower right arm was missing and his right humerus shows severe at-

rophy, likely due to disuse. This pattern has been interpreted to indicate a substan-

tial injury that required or otherwise resulted in amputation or wasting away of the

lower arm. Additionally, Shanidar 1 suffered from severe arthritis in his feet and bony

growths in his inner ear that would have signi�cantly impaired his hearing. He also

exhibited extensive anterior tooth wear, matching the pattern of wear found among

modern populations who use their teeth as a tool. Rather than an anomaly, the type

of injuries evident in Shanidar 1 are similar to those found in many other Nean-

derthal fossils, revealing injuries likely sustained from hunting large mammals as

well as demonstrating a long life of physical activity.

Figure 11.10 Like many other Neanderthals, Shanidar 1 has a lifetime of injuries

recorded in his bones. Shanidar 1 sustained—and healed from—an injury to his face

that would have likely caused blindness. His lower right arm was missing and his right

humerus shows severe atrophy, likely due to disuse.

The pattern of injuries is as signi�cant as the fact that Shanidar 1 and other injured

Neanderthals often show evidence of having survived their severe injuries. One of

the earliest known Neanderthal discoveries—the one on whom misinformed analysis

shaped the stereotype of the species for nearly a century—is the La Chapelle-aux-

Saints Neanderthal. The La Chapelle Neanderthal had a damaged eye orbit that likely

caused blindness and suffered arthritis of the spine. He had also lost of most of his

teeth, many of which he had lived without for so long that the mandibular and max-

illary bones were partially reabsorbed due to lack of use. The La Chapelle Nean- Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

derthal was also thought to be at least in his mid-40s at death, an old age for the

rough life of the Late Pleistocene, giving rise to his nickname, “the Old Man.” To have

survived so long with so many injuries that obviously precluded successful large

game hunting, he would have had to have been taken care of by others. Such care-

taking behavior is also evident in the survival of other seriously injured Nean-

derthals, such as Shanidar 1. Long thought to be a hallmark human characteristic,

taking care of the injured and elderly, to the extent of even preparing or pre-chew-

ing food for those without teeth, indicates strong social ties among Neanderthals.

The care expressed in taking care of the sick or injured may have been expressed

upon death as well. Full Neanderthal skeletons are not uncommon in the fossil

record, and many of these skeletons were so well preserved due to having been

placed in deliberate burials. These burials appear intentional, as the graves are dug

down a bit, and the bodies found in the graves are in speci�c positions quite distinct

from the natural position the body automatically goes into after death during rigor

mortis. Neanderthal burials are often in a �exed position, or fetal position. Discov-

eries of pollen in a grave at the Shanidar site in the 1960s led scientists to think that

perhaps Neanderthals had deliberately placed �owering plants in the grave, an indi-

cation of ritual ceremony or spirituality so common in modern humans. But future

investigations have raised some doubt about this conclusion. The pollen may have

been brought in by burrowing rodents. Claims of grave goods or other ornamenta-

tion in burials are similarly debated, although possible.

Some tantalizing evidence for symbolism, and debatably, ritual, is the frequent oc-

currence of natural pigments, such as ochre (red) and manganese dioxide (black) in

Neanderthal sites. Such pigments could have been used for art, like some of the

spectacular cave paintings produced by modern humans who lived in this area after

the Neanderthals. However, how these pigments were actually used by Neanderthals

themselves is unclear, as there is very little evidence of art or paintings in Mouste-

rian sites. One exception may be the recent discovery in Spain of a perforated shell

that appears to be painted with an orange pigment, which may be some of the best

evidence of Neanderthal art and jewelry. However, many pigments also have proper-

ties that make them good emulsi�ers in adhesive (like for attaching a stone tool to a

wooden handle) or useful in tanning hides. So the presence of pigment may or may

not be associated with symbolic thought, but it at the very least shows a technologi- Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

Figure 11.11 Artistic reconstruction of Neanderthals.

cal sophistication beyond that exhibited by earlier archaic hominins and clearly

counters the old stereotypes of Neanderthals as dumb, thoughtless brutes.

The more recent time period in which Neanderthals lived and extensive excavations

completed across Europe allow for a much more complete archaeological record

from this time period. Additionally, the increased cultural complexity such as com-

plex tools and ritual behaviors expressed by Neanderthals left a more detailed

record than previous hominins. Intentional burials enhanced preservation of the

dead and potentially associated ritual behaviors. Such evidence allows for a more

complete and nuanced picture of this species.

Additional analyses are possible on many Nean-

derthal �nds, due to increased preservation of

bone, the amount of specimens that have been un-

covered, and the recency in which Neanderthals

lived. These additional studies include the exami-

nation of dental calculus and even DNA analysis.

While limited, some samples of Neanderthal DNA

have been successfully extracted and analyzed.

Studies thus far have identi�ed speci�c genetic

markers that show some Neanderthals were light-skinned and probably red-haired

with light eyes. Genetic analyses, different than the typical hominin reconstruction

done with earlier species, allow scientists to further investigate soft tissue markers

of Neanderthals and other more recent hominin species. These studies and Nean-

derthal cultural behavior have given scientists a wealth of information to study and

offer striking conclusions regarding Neanderthal traits, their physical appearance,

and their culture, as re�ected in these artists’ reconstructions (Figure 11.11).

The Neanderthals’ more complicated behavior likely stems, in part, from their larger

brains. Evidence shows that raw materials used by Neanderthals came from dis-

tances as far away as 100 km. This could indicate a variety of things regarding Nean-

derthal behavior, including a limited trade network with other Neanderthal groups,

or simply a large area scoured by Neanderthals when collecting raw materials. Addi-

tionally, we know that Neanderthals lived in groups and may have relied on their

group members for survival. Shanidar 1 and the “Old Man at La Chapelle” would have

struggled to acquire and consume food on their own, strongly suggesting that they

may have been assisted by relatives of other group members. In other nonhuman

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primates (like chimpanzees) and earlier hominins, injured individuals would have

been left on their own, to either survive or perish.

The impressive cultural innovations and behavioral expansions seen in the Nean-

derthals would have required at least a basic form of communication in order to

function, which suggests to many researchers that Neanderthals spoke. The chal-

lenge with this line of research is that speech, itself, of course is not preserved, so

indirect evidence must be used to support this conclusion. It is thought that Nean-

derthals would have possessed some basic speech, as evidenced from a variety of

sources, including throat anatomy and genetic evidence. There is only one bone in

the human body that could demonstrate if a hominin was able to speak, or produce

clear vocalizations like modern humans, and that is the hyoid, a U-shaped bone that

is found in the throat and is associated with the ability to precisely control the vocal

cords. Very few hyoid bones have been found in the archaeological record; however,

a few have been uncovered in Neanderthal burials. The shape of the Neanderthal hy-

oid is nearly identical to that of modern humans, pointing to the likelihood that they

had the same vocal capabilities as modern humans. Genetic evidence has been de-

bated concerning the likelihood of speech. Geneticists have uncovered a possible

mutation, the FOXP2 gene, that has been linked to the ability to speak and that both

modern humans and Neanderthals possess. However, some scientists counter those

�ndings, indicating that the study’s sample size was too small to make sweeping

conclusions that the FOXP2 gene is what accounts for human or Neanderthal

speech. Finally, scientists have also pointed to the increasingly complex cultural be-

havior of Neanderthals as a sign that symbolic communication, likely through

speech, would have been the only way to pass down the skills needed to make, for

example, a Levallois blade or to position a body correctly for intentional burial.

Neanderthal Intelligence

One of the enduring questions about Neanderthals centers on their intelligence,

speci�cally in comparison to modern humans. Brain volume indicates that Nean-

derthals certainly had a large brain, but it continues to be debated if Neanderthals

were of equal intelligence to modern humans. Brain volume, cultural complexity, Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

tool use, and compassion toward their kind all point to an increase in intellect

among Neanderthals when compared to previous hominins.

However, there have been several studies that seem to indicate that while Nean-

derthals did have a large brain volume and were far more advanced than their previ-

ous relatives, they may not have been nearly as intelligent as or may have even

lacked the intellectual abilities possessed by modern humans. Euluned Pearce and

colleagues, from the University of Oxford, noted that based on cranial endocasts,

the frontal lobe of Neanderthals and modern humans are almost identical. However,

Neanderthal faces and other cranial features were larger. Neanderthals possessed

larger eye sockets, and the larger eyes they held would have helped Neanderthals

see in the low light levels common for the latitudes at which they lived. Because of

the larger eye sockets, the visual cortex—the portion of the brain involved in pro-

cessing visual information—would have had to have been enlarged, as well. This

would have left Neanderthals with less neural tissue for other components of the

brain, including those that would have aided them in dealing with expansive social

networks, one of the differences that it has been suggested existed between Nean-

derthals and modern humans.

New research is suggesting additional differences between Neanderthal brains and

our own. Research being conducted by geneticist John Blangero and his team from

the Texas Biomedical Research Institute are examining genes involved in certain dis-

eases among modern populations. His team has also looked at brain structure and

function. Comparing data from the Neanderthal genome against MRI data from his

modern study participants, Blangero and his team discovered that some Nean-

derthal brain components were very different, and smaller, than those in the mod-

ern sample. These areas include decreased gray matter surface area, a smaller

amygdala, and less white matter. These three regions are important in the process-

ing of information and controlling emotion and motivation, as well as overall brain

connectivity. In short, as Blangero stated at the annual meeting of the American As-

sociation of Physical Anthropologists in 2014, “Neanderthals were certainly cogni-

tively adept,” although their speci�c abilities may have differed from modern hu-

mans’ in key areas (qtd. in Wong 2015), a point echoed in other recent genetic stud-

ies comparing Neanderthal and anatomically modern human brains (el-Showk 2019).

Finally, scientists are fairly certain that Neanderthal brain development after birth

was not the same as that of modern humans. After birth, anatomically modern Homo

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sapiens babies go through a critical period of brain expansion and cognitive devel-

opment. It appears that Neanderthal babies’ brains did not follow the same develop-

mental pattern. This could also be related to the length of the period of childhood.

Modern humans enjoy an extended period of childhood, which, among many things,

allows children to engage in imaginative play and develop creativity. Child develop-

ment studies indicate that children who have extended, undirected play opportuni-

ties will be better off academically and socially later in life than their peers who had

less play opportunities. Based on their anatomical developments, it appears that Ne-

anderthals had a limited childhood. It has been suggested that this limited time for

play and developing a creative mind might have limited adult creativity and how

successful they were as a species, in the long run.

The exact nature of Neanderthal intelligence remains under investigation, however.

Some studies disagree with the idea that Neanderthal intelligence had limitations

compared to our own, noting that there is extensive evidence showing that Nean-

derthals displayed limb asymmetry. Their tools also have wear marks indicating that

they were hand-dominant. It has been established that favoring the right hand is

one key marker between modern humans and chimpanzees, and that handedness is

likely also related to language development, in the form of bilateral brain develop-

ment. That Neanderthals likely were hand-dominant as well suggests that they at

least had many of the preconditions for human speech and likely experienced simi-

lar bilateral brain development to our own.

In addition to cut marks on animal bones, there are marks on Neanderthal teeth that

demonstrate hand dominance. Neanderthal upper incisors, or front teeth, show not

only wear from using their teeth when preparing hides or cordage but also cut

marks that were created by using their teeth as a third limb when eating. The “stuff-

and-cut method,” noted by David Frayer, would have seen the Neanderthal hold a

piece of meat in their teeth and pull it taut with one hand, and then, using their

other hand, their dominant one, cut meat off the slab. When looking at 17 Nean-

derthals and their tooth wear, only two do not show markings made by a right-hand

dominant individual. This research suggests another similarity between Neanderthal

and modern human brains and their associated intelligence.

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THE MIDDLE STONE AGE: NEANDERTHAL CONTEMPORARIES IN AFRICA

While Neanderthals made their home on and adapted to the European and Asian

continents, evidence of fossil humans in Africa show they were also adapting to their

local environments. These populations in Africa exhibit many more similarities to

modern humans than Neanderthals, as well as overall evolutionary success. While

the African fossil sample size is smaller and more fragmentary than the number of

Neanderthal specimens across Europe and Asia, the African sample is interesting in

that it represents a longer time period and larger geographical area. This group of

fossils, often represented under the name of “Middle Stone Age,” or MSA, dates to

between 300,000 and 30,000 years ago across the entire continent of Africa. As with

archaic Homo sapiens, there is much variability seen in this African set of fossils.

There are also a few key consistent elements: none of them exhibit Neanderthal

skeletal features; instead, they demonstrate features that are increasingly consistent

with anatomically modern Homo sapiens.

Similarities to Neanderthals and MSA contemporaries in Africa are seen, however, in

their behavioral adaptations, including stone tools and other cultural elements. The

tools associated with the specimens living in Africa during this time period are, like

their physical features, varied. In some parts of Africa, namely Northern Africa, stone

tools from this time so closely resemble Neanderthal tools that they are classi�ed as

Mousterian. In sub-Saharan Africa, the stone tools associated with these specimens

are labeled as Middle Stone Age, or MSA. Some scholars argue that these could also

be a type of Mousterian tools, but they are still typically subdivided based on geo-

graphical location.

Recall that Mousterian tools were much more advanced than their Acheulean prede-

cessors in terms of how the stone tools were manufactured, the quality of the

stones used, and the ultimate use of the stone tools that were made. In addition, re-

cent evidence suggests that MSA tools may also have been heat treated—to improve

the quality of the stone tool produced. Evidence for heat treating is seen not only

through advanced analysis of the tool itself but also through the residue of �res

from this time period. Fire residues show a shift over time from small, short �res fu-

eled by grasses (probably intended for cooking) to larger, more intensive �res that

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required the exploitation of dry wood, exactly the type of �re that would have been

needed for heat treating stone tools.

Other cultural elements seen with specimens dating to the MSA include use of ma-

rine (sea-based) resources for their diet, manufacture of bone tools, use of adhesive

and compound tools (e.g., hafted tools), shell bead production, engraving, use of pig-

ments (such as ochre), and other more advanced tool-making technology (e.g., mi-

crolithics). While many of these cultural elements are also seen to a limited extent

among Neanderthals, many of the developments at MSA sites are far more complex

than what is demonstrated with Neanderthal sites. Several explanations have been

posited to explain this expansion of cultural complexity. It has been suggested that

MSA cultural expansion was a response to climate change. It has also been sug-

gested that perhaps the MSA cultural expansion was due to an increased use of lan-

guage, which triggered increased symbolic thought. Others have suggested that the

cultural expansion of the MSA was due to the increase of marine resources in their

diet, which included more fatty acids and may have aided their cognitive develop-

ment. Still others have suggested that the increased cultural complexity was due to

an increase in competition and interaction among groups, which spurred competi-

tion to innovate with increased cultural complexity. Recent studies suggest that per-

haps the best explanation for the marked cultural complexity and diversity demon-

strated by MSA cultural artifacts is best explained by the simple fact that they lived

in diverse habitats. This would have necessitated a unique set of cultural adaptations

for each habitat type (for example, specialized marine tools would have been needed

along coastal sites but not at inland locations). Simply put, the most useful adapta-

tion of MSA was their �exibility of behavior and adaptability to their local environ-

ment. As noted previously in this chapter, �exibility of behavior and physical traits,

rather than specialization, seems to be a feature that was favored in hominin evolu-

tion at this time.

WHERE DID THEY GO? THE END OF NEANDERTHALS

While MSA were increasingly successful and ultimately transitioned into modern

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Homo sapiens, Neanderthals disappear from the fossil record by around 35,000

years ago. The main question that lingers, however, is what happened to them. We

know, based on genetics, that modern humans come largely from the modern peo-

ple who occupied Africa around 300,000 to 100,000 years ago, at the same time that

Neanderthals were living in the icy portions of northern Europe and Asia. Modern

humans expanded out of Africa around 60,000 to 40,000 years ago, rapidly entering

areas of Europe and Asia inhabited by Neanderthals and likely other populations of

archaic hominins. Despite intense interest and speculation in �ctional works about

possible interactions between these two groups, there is very little direct evidence

of either peaceful coexistence or aggressive encounters. It is clear, though, that

these two closely related hominins shared Europe for thousands of years, and recent

DNA evidence suggests that they at least occasionally interbred. Geneticists have

found traces of Neanderthal DNA (1% to 4%) in modern humans of European and

Asian descent that is not present in modern humans from Africa. This is generally

interpreted as indicating limited regional interbreeding with Neanderthals. Interest-

ingly, while some studies suggest interbreeding was often problematic for their off-

spring, gene �ow from Neanderthals may have bene�ted modern Homo sapiens.

David Enard and Dmitri Petrov (2018) compared sequenced Neanderthal and modern

human DNA, observing that the portions of Neanderthal DNA in modern humans of

European descent seem to confer defense against viral pathogens that they would

have been exposed to as they moved out of Africa.

While some interbreeding likely occurred, as a whole, Neanderthals did not survive.

What is the cause for their extinction? This question has fascinated many re-

searchers and several possibilities have been suggested that deserve some explo-

ration. Possibilities include the following:

The climate began changing considerably from the height of Neanderthal ex-

pansion. At the time that Neanderthals were disappearing from the fossil

record, the climate went through both cooling and warming periods—each of

which posed challenges for Neanderthal survival (De�eur and Desclaux 2019;

Staubwasser et al. 2018). It has been argued that as temperatures warmed,

large-bodied animals, well adapted to cold weather, moved farther north to �nd

colder environments or face extinction themselves. A shifting resource base

could have been problematic for continued Neanderthal existence, especially as Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

additional humans, in the form of modern Homo sapiens, began to appear in Eu-

rope and were competing with them for a smaller pool of available resources.

It has been suggested that the eruption of a European volcano 40,000 years ago

could have put a strain on available plant resources (Golovanova et al. 2010). The

eruption would have greatly affected local microclimates, reducing the overall

temperature enough to alter the growing season.

Possible differences in cognitive development may have limited Neanderthals in

terms of their creative problem solving. It has been argued that as much as they

were biologically specialized for their environment, the nature of their intelli-

gence might not have offered them the creative problem solving skills to rethink

their cultural adaptations and innovate ways to adapt their culture when faced

with a changing environment (Pearce, Stringer, and Dunbar 2013).

There is evidence that suggests reproduction may have posed challenges for

Neanderthals. Childbirth was thought to have been at least as dif�cult for fe-

male Neanderthals as anatomically modern Homo sapiens (Weaver and Hublin

2009). Female Neanderthals may have become sexually mature at an older age,

even older than modern humans. This delayed maturation could have kept the

Neanderthal population size small. A recent study has further suggested that

male Neanderthals might have had a genetic marker that would have had nega-

tive impacts on the longevity of the Neanderthal population (Mendez et al.

2016).

We would be remiss if we did not point out that the end of Neanderthal exis-

tence also overlaps with modern human expansion into northern Europe and

Asia. There is no conclusive direct evidence to indicate that Neanderthals and

modern humans lived peacefully side by side, nor that they engaged in brutal

warfare, but by studying modern societies and the tendencies of modern hu-

mans, it has been suggested that modern humans may not have warmly em-

braced their close but slightly odd-looking cousins when they �rst encountered

them (Churchill et al. 2009). Competition for resources may have been the cause

of the Neanderthals’ decline (Gilpin, Feldman, and Aoki 2016). It is also com-

pletely possible that modern humans gave Neanderthals diseases to which they

previously had little to no exposure, causing a mass population decline similar

to what happened when the invading Spanish wiped out the Mayan and Aztec

populations (Houldcroft and Underdown 2016). Estimates of energy expendi-

tures suggest Neanderthals had slightly higher caloric needs than modern hu-

mans (Venner 2018). When competing for similar resources, the slightly greater

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ef�ciency of modern humans might have helped them experience greater suc-

cess in the face of competition—at a cost to Neanderthals.

Finally, less dramatically yet still signi�cantly, even a small but continuous de-

crease in fertility would have been enough to result in the extinction of Nean-

derthals (Degioanni et al. 2019).

As Neanderthal populations were fairly small to begin with (estimated between

5,000 and 70,000 individuals) (Bocquet-Appel and Degioanni 2013), one or a combi-

nation of these factors could have easily led to their demise. As more research is

conducted, we will likely get a better picture of exactly what led to Neanderthal

extinction.

DENISOVANS

While Neanderthals represent one regionally adapted branch of the archaic Homo

sapiens family tree, recent discoveries in Siberia and the Tibetan Plateau have sur-

prised paleoanthropologists by revealing yet another population that was contem-

porary with archaic Homo sapiens, Neanderthals, and modern Homo sapiens. The ge-

netic analysis of a child’s �nger bone and an adult upper third molar from Denisova

Cave in the Altai Mountains in Siberia by a team including Svante Pääbo shocked

even the researchers when they discovered that the mitochondrial and nuclear DNA

sequences revealed distinct genetic differences from all known archaic populations.

Dubbed “Denisovans” after the cave in which the bones were found, this population

is more closely related to Neanderthals than modern humans, suggesting the two

groups shared an ancestor who split from modern humans �rst, then the Nean-

derthal-Denisovan line diverged more recently.

Denisovans share up to 5% of their DNA with modern Melanesians, aboriginal Aus-

tralians, and Polynesians, and 0.2% of their DNA with other modern Asian popula-

tions and Native Americans. Additional studies have suggested two separate in-

stances of interbreeding between humans and Denisovans, whom researchers have

yet to classify as a separate species, pending additional information.

Genetic analysis reveals that Denisovans potentially had at least three populations

Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

and had genetic adaptations for life at high altitudes, preventing them from develop-

ing altitude sickness and hypoxia. Recent publications also suggest that Denisovans

shared these genetic adaptations with modern Tibetans through interbreeding

30,000 to 40,000 years ago. Stone tools similar to those found in Siberia have also

been found in the Tibetan plateau, suggesting the possibility that Denisovans could

have inhabited this extreme environment where the average annual temperature is

close to 0℃ and the altitude is more than a kilometer (about 4,000 feet) above sea level. Research continues on this population and other archaic populations in the

hopes of discovering more DNA evidence that can con�rm current hypotheses and

clarify our understanding of the complex interactions of archaic groups.

To stay up to date with new discoveries, consider following organizations such as

the Smithsonian’s Human Origins Program on social media

(https://www.facebook.com/smithsonian.humanorigins/).

MODELS OF MODERN HUMAN DISTRIBUTION

There has been much debate in anthropological circles concerning the origin of

modern humans and their relationship with other hominin populations. Three com-

peting models have been developed and seek to explain the fossil evidence and what

it indicates for modeling human origins.

The �rst model, the Out-of-Africa Hypothesis, states that modern humans origi-

nated in Africa, replacing archaic populations found elsewhere in the Old World.

Theorists including Christopher Stringer (1996) argue that each archaic population

comprised a separate species, making interbreeding between populations impossi-

ble. Admixture resulting from gene �ow would not have been possible according to

this model.

The second, called the Multiregional Continuity Hypothesis, states that modern

Homo sapiens are directly derived from Homo erectus and evolved in place after

Homo erectus left Africa and populated areas in Asia and Europe. Milford Wolpoff ar-

gues that interbreeding between regions and across regional boundaries contrib- Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

uted to gene �ow that maintained Homo sapiens as a single species throughout the

Old World, despite regional variation.

The third model, dubbed the Assimilation Hypothesis, draws from the strengths of

both previous models, attempting to recognize some of the evidence that was not

previously addressed and blending the fossil and DNA evidence together into one

cohesive view. In this model, modern humans originated in Africa, spreading out-

ward into Asia and Europe and interbreeding with more archaic forms they encoun-

tered along the way. For example, while the Out-of-Africa model argues that inter-

breeding would have been impossible, many fossils have been found with what ap-

pear to be a mixture of archaic and more modern traits, suggesting interbreeding

between populations, such as Neanderthals and modern humans. DNA evidence in-

creasingly also suggests that, while limited, interbreeding between modern Homo

sapiens and Neanderthals or modern Homo sapiens and Denisovans occured in at

least three instances. While this is more interbreeding than allowed under the Out-

of-Africa Hypothesis, it is considerably less than modeled in the Multiregional Con-

tinuity Hypothesis. The Assimilation Hypothesis, argued by Eric Trinkaus (2006,

2007) and others, represents an attempt to incorporate all lines of evidence, al-

though new research will tell whether it can capture the full complexity revealed in

the next generation of hominin studies, such as that revealed by ancient DNA.

SPECIAL TOPIC: ANCIENT DNA

Robyn Humphries, MSc., University of Cape Town

[email protected]

Ancient DNA has provided us with new insights into our evolutionary his-

tory that cannot be garnered from the fossil record. It has also assisted

with the discovery of the new hominin species the Denisovans, for which

little fossil evidence is available. It has helped us better understand the

evolution of Neanderthals, Denisovans, and modern humans. Through

Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

genomic data and the use of population genetics, we have been able to

make some inferences about Neanderthal and Denisovan population

structure and relationships within these populations as well as between

different groups of hominins. It has also helped to answer some very im-

portant questions about what happened when modern humans migrated

out of Africa and encountered these European/Asian hominins. Two the-

ories dominated the debate regarding the evolution of modern humans:

the multiregional theory and the Out-of-Africa theory. Though it was

clear—based on a plethora of evidence—that modern humans evolved in

Africa, what happened when our ancestors migrated out of Africa was

still questioned. Ancient DNA (aDNA) helped answer this question, indi-

cating that modern humans interacted with other archaic hominins such

as Neanderthals and Denisovans. We will discuss all the above in this

section.

Se�uencing Ancient Genomes

The �rst successful sequencing of aDNA from an archaic hominin took

place in 1997 with the sequencing of mitochondrial DNA (mtDNA) from

the Neanderthal-type specimen from Feldhofer Cave. Sequencing of a

portion of the mitochondrial genome provided molecular evidence that

Neanderthals belonged in a clade separate from modern humans and that

they were four times more different from modern humans than modern

humans were from each other based on mtDNA data. mtDNA is ideal for

sequencing from fossil material because of the abundance of mtDNA

when compared to nuclear DNA.

Sequencing of nuclear DNA would not occur until more than ten years

later. The �rst nuclear genomic sequence representing Neanderthals was

produced by sequencing three individuals and using their sequences to

create a composite draft Neanderthal genome in 2010. The �rst high-

coverage sequence of a single Neanderthal was that of a female Nean-

derthal who lived in Siberia, which was published in 2014, followed by an-

other high-coverage sequence from a female Neanderthal whose remains

Previous: Early Members of the Genus Homo

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were found in the Vidja cave in Croatia, which was published in 2017.

High-coverage sequences are produced when the genome has been se-

quenced multiple times. This is to ensure that the sequences obtained

are a true re�ection of the genomic sequence and not due to errors that

occur during the process of sequencing. If you have many sequences

from the same region and there is one sequence that has a slight differ-

ence while the other copies are all the same, it is easier to identify the

variant as an error.

Collecting and Se�uencing aDNA

Ancient DNA can be collected from many different sources including soft

tissue such as skin and muscle, hair, paleo feces, soils, and sediments.

However, in the case of ancient hominins, they are often collected from

bone and teeth. When collecting aDNA, usually around 100 mg to 500 mg

of bone powder needs to be collected. Because extraction of aDNA re-

quires destruction of part of the bone, and the morphology of the skeletal

element might be informative, care needs to be taken when deciding

which part of the bone is sampled. It is advised that multiple samples be

taken so that sequencing is repeated to show reproducibility of results.

Contamination is an important consideration when it comes to sequenc-

ing aDNA; thus, it is best that samples that are used had minimal handling

before extraction of DNA.

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Figure 11.12 An illustration of the different types of DNA you may �nd after DNA extraction is performed on bone or other samples.

It has taken a lot of time and much trial and error to sequence these an-

cient genomes because of the fragility of DNA. When sequencing ancient

DNA, it is important to consider that aDNA sequences are usually short

due to degradation, there are very few copies of the endogenous aDNA.

Endogenous aDNA is the DNA that comes from the bone and was present

in the tissue before decomposition of the body and before the introduc-

tion of DNA from other sources, such as microbes or contamination from

modern humans, which is known as exogenous DNA (Figure 11.12).

There are also modi�cations that occur to aDNA that are a result of

chemical reactions known as deamination. Deamination results in Cyto-

sine (C) to Thymine (T) conversions, which are mostly at the 5’ end (

5 prime end)of the DNA fragment. This in turn results in Guanine (G) to

Adenine (A) substitutions on the 3’ end (3 prime end)of the DNA frag-

ment. Thus, there are sequence changes in aDNA that might not re�ect

the original hominin sequence. These changes can be helpful when dif-

ferentiating between aDNA and modern human DNA contamination. The

environment in which the DNA is preserved also plays a signi�cant role.

Previous: Early Members of the Genus Homo

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DNA preserves well in cold conditions such as permafrost, which extends

the lifespan of DNA signi�cantly. aDNA has also been recovered from ma-

terial found in drier environments under special conditions. Factors such

as water percolation, salinity, pH, and microbial growth all affect the

preservation of aDNA.

In extraction of DNA from modern samples where DNA is still intact, the

DNA strands are usually long and this is ideal for sequencing. However,

aDNA samples are often composed of small fragments of DNA, usually 100

bp to 300 bp long. Initially this posed a big problem with usual PCR pro-

cedures used to sequence DNA. This changed with the advent of high

throughput sequencing, which has revolutionized sequencing the

genomes of ancient hominins. High throughput sequencing allows for the

parallel sequencing of many fragments of DNA in one reaction. It also

doesn’t require any knowledge of the target sequence. Thus, we can se-

quence as much of the available aDNA as possible. Because the high

throughput sequencing method does not discriminate between endoge-

nous aDNA from hominins and contamination from modern humans and

microbial DNA, it is important to either ensure that there is as little con-

tamination as possible or create methods that allow for differentiation

between modern human sequences and ancient hominin sequences. Both

methods have been used when sequencing hominin aDNA.

�e Discovery of the Denisovans

The Denisovans are named after the cave in which they were discovered,

the Denisovan Cave in the Altai Region of Siberia. Denisovans were ini-

tially identi�ed as a distinct group based on analysis of mtDNA sequences

indicating that they had haplotypes outside the range of variation of

modern humans and Neanderthals. A haplotype is a set of genetic vari-

ants located on a single stretch of the genome. This unique combination

of variants on a stretch of the genome can be used to differentiate groups

who will have different combinations of variants. Some haplotypes may

be more similar to one another. The more similar two haplotypes are, the

Previous: Early Members of the Genus Homo

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more closely related they are. Dubbed lineage X, the mtDNA sequence

showed that Denisovans diverged from modern humans and Nean-

derthals at around 1 million years ago (mya). The subsequent high-cover-

age sequence of a Denisovan 3 nuclear genome showed that Denisovans

are a sister group to Neanderthals and thus more closely related than in-

dicated by the mtDNA data.

The mtDNA and nuclear DNA provided con�icting data regarding the re-

lationships between Denisovans and Neanderthals. Because mtDNA and

nuclear DNA have different patterns of inheritance, they can paint differ-

ent pictures about the relationships between two groups when used to

construct phylogenies. The Denisovans are thought to have a mtDNA se-

quence that is derived from an ancient hominin group that hybridized

with Denisovans and introduced the mtDNA sequence.

Sequences are also available for three other Denisovans, Denisovan 2, 4,

and 8. aDNA sequences have been used to estimate the ages of the

Denisovans. Using a combination of usual dating methods (such as radio

carbon dating and uranium dating) as well as genetic data, it has been de-

termined that Denisovans occupied the Denisovan cave from around 195

kya to 52 kya to 76 kya. DNA can assist with dating because younger se-

quences will have accumulated more sequence changes from the putative

common ancestral sequence than older samples. This is because younger

sequences would have had more time over which changes to the DNA se-

quence through mutation could occur. Thus, it is possible to conclude

based on sequence data that Denisovan 2 is 54.2 kya to 99.4 kya older

than Denisovan 3 and 20.6 kya to 37.7 kya older than Denisovan 8. Molec-

ular data indicates that Neanderthals and Denisovans separated between

381 kya and 473 kya and that the branch leading to Denisovans and mod-

ern humans diverged around 800 kya. Denisovans are also more closely

related to another set of fossils found in the cave Sima de los Huesos

dated to 480 kya. Thus, the split between Neanderthals and Denisovans

must have occurred before 480 kya.

Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

What Can We Learn about Population Structure of the Neanderthals and Denisovans from aDNA

Ancient DNA has helped us understand the demographics of Nean-

derthals and Denisovans and make inferences about population size and

history. The genomic data from Neanderthals indicates that their popula-

tion was small toward the end of their existence. This is supported by

three lines of evidence.

The �rst is by using coalescent methods. This is the process used to de-

termine which population dynamics in the past are most likely to give

rise to the genetic sequences we have, allowing us to use genetic se-

quences to estimate population genetic parameters in the past. It can be

used to understand recombination, population subdivision, and variable

population size.

The second indicator that Neanderthals and Denisovans had smaller pop-

ulation size is that these groups carried many deleterious genomic vari-

ants. Genomic variants are considered deleterious when they are found

in protein-coding regions of the genome and the change in genomic se-

quence translates to a change in amino acid sequence of the protein.

Changes in amino acid at a certain section in the protein could affect the

functioning of the protein—these types of changes in genomic sequence

are known as non-synonymous mutations. Synonymous mutations also

occur in protein-coding regions of the genome, but the amino acid se-

quence does not change because of changes in the genomic sequence.

Changes in amino acid and subsequent protein sequence can change the

protein function and thus are more likely to be deleterious and weeded

out by natural selection. The ratio of synonymous to

non-synonymous mutations can give you an indicator of whether there

are more deleterious variants than expected. Denisovans and Nean-

derthals have a higher ratio of non-synonymous to synonymous muta-

tions when compared to contemporary modern human populations. This

is an indicator of a small population size, because if the population were Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

larger, natural selection would have acted on these deleterious variants

and weeded them out.

A third indicator of small population size is that the Neanderthals se-

quenced thus far have low levels of heterozygosity, a measure of how

many genes within a genome are made up of more than one variant. Each

individual has two copies of the same gene: one is inherited from their

mother and the other from their father. Variations of the same gene are

known as alleles, which are versions of the same gene with h different

sequences. If the alleles inherited from both parents are the same, the in-

dividual is homozygous for that gene; if the alleles inherited are different,

the individual is heterozygous for that gene. Heterozygosity is measured

by looking at how many times you happen to �nd two different alleles

within a certain stretch of DNA. When you �nd many regions on the

genome with different alleles, there is a high level of heterozygosity.

When you �nd very few positions where there are two different alleles,

this results in a low level of heterozygosity.

Ancient Neanderthal genomes also revealed that there were consan-

guineous relations between Neanderthals. One Neanderthal female is

thought to be the offspring of relations between either half-siblings, an

uncle/aunt and niece/nephew, or a grandfather/grandmother and

grandson/granddaughter. This was determined by looking at the

stretches of homozygosity  in her genome that were longer than ex-

pected and could not be explained by small population size alone.

Denisovans also had low levels of heterozygosity indicating a smaller

population size. However, there is no indication yet of inbreeding among

the Denisovans, as none of the individuals sequenced thus far show long

stretches of homozygosity. Thus, both Denisovans and Neanderthals had

small populations size and low levels of genetic diversity when compared

to modern humans.

How Se�uencing Archaic Genomes Can Help Understand Our Own Uni�ue Evolutionary

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Next: Modern Homo sapiens

Trajectory as Modern Humans

Not only did the sequencing of archaic genomes allow us to learn more

about Neanderthals and Denisovans, it gave us important insights into

our own evolution. Previously the human genome could only be com-

pared to our closest living relatives, the great apes, which helped us iden-

tify unique derived genomic changes that occurred in humans since our

split from the last common ancestor between chimps and humans. Nean-

derthal and Denisovan genomes provided another set of comparative

samples that could help us identify changes that were unique to modern

humans occurring after our split from the last common ancestor with

Neanderthals/Denisovans. We now have an opportunity to identify ge-

netic variants that may have contributed to our success as a species.

Hybridization between Hominin Groups

Ultimately aDNA provides us with great insight into interactions between

modern humans migrating out of Africa and other hominins that evolved

in Europe and Asia. There was speculation that hybridization occurred

due to the intermediate morphology of some fossil remains. The follow-

ing hypothesis was tested: if hybridization between modern humans and

Neanderthals occurred, Neanderthals would have more shared genomic

variants with some modern human populations than with others. If this

was true, hybridization between Neanderthals and humans happened.

This comparison showed that Neanderthals shared more genomic vari-

ants with Europeans and Asians than with the African individuals. This

difference in relatedness was signi�cant. This indicated that there had

been hybridization between Neanderthals and modern humans.

From the genetic data, we know that different groups have different

amounts of Neanderthal and Denisovan contributions. For example, Eu-

ropeans have a smaller proportion of Neanderthal-derived genes than

East Asians. Thus, there was more admixture into ancestral East Asian Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

populations than into ancestral European populations. This is unexpected

because Neanderthals fossils are mostly found in West Asia and Europe.

Oceanians (Melanesians, Australian aborigines, and other Southeast Asian

islanders) have a higher proportion of their DNA derived from Deniso-

vans. These populations also have longer stretches of Denisovan DNA.

Since DNA in chromosomes get exchanged and “break apart” between

each generation (in the process known as genetic recombination), this

implies that the admixture event between the Denisovan and human an-

cestors of these populations is more recent than the admixture events

between Neanderthals and modern humans. Genomic recombination

breaks down introgressed regions (inherited from different species or

taxon) into smaller segments in every successive generation, thus longer

stretches of introgressed DNA indicates that hybridization occurred

more recently.

Initially, some researchers believed that populations outside of Africa had

higher proportions of Neanderthal DNA due to population substructure,

which existed in the ancestral population before the split between mod-

ern humans and Neanderthals. According to these researchers, Eurasian

populations retained these ancient sequences by chance, through genetic

drift. These would be shared derived genomic sequences between Nean-

derthals and modern humans outside of Africa. However, studies of the

shared regions indicate that these genomic regions are most likely the

result of introgression, which is the transfer of genetic information from

one species to another because of hybridization between them and re-

peated backcrossing.

Divergence time is important for determining whether shared sequences

are a result of introgression or more ancient substructure.

Divergence time is a measure of how long two sequences have been

changing independently. It is measured by looking at how many differ-

ences there are between the two sequences. The longer the two se-

quences have been changing independently, the more differences they

will accumulate, which will result in a longer divergence time. By measur-

ing the divergence time between the introgressed regions in modern hu-

man genomes and the Neanderthal sequences, researchers can calculate Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

that the shared sequences are recent as well as date to when the two

taxa made secondary contact. This is also well after the initial population

split between modern humans and Neanderthals occurred. If they were

shared derived genomic sequences, then we would expect longer diver-

gence times between the introgressed Neanderthal genomic sequences

in modern humans and the Neanderthal genome. Hybridization has oc-

curred between hominins at different times over the last 100 kya as

shown in Figure 11.14.

The Neanderthal and Denisovan genomes would provide de�nitive proof

that there was interaction and interbreeding between humans, Nean-

derthals, and Denisovans around 44 to 55 kya, with data suggesting that

there was an admixture event as far back as 100 kya. There has been gene

�ow from Neanderthals and Denisovans into modern human populations,

between Neanderthals and Denisovans, and from modern humans into

Neanderthals.

Because of the climate in Africa, it has been dif�cult or impossible due to

fossilization to extract aDNA from African fossil remains. However, analy-

sis of genomes of modern African populations indicate that there was ad-

mixture between modern humans and other hominins within Africa (Fig-

ure 11.13). Thus, hybridization is an important part of human evolution

and has affected our evolution within and outside of Africa.

The oldest modern human that has been sequenced Ust’-Ishim is from

Europe and is dated to around 49 kya. He had a similar amount of Nean-

derthal-derived genes as modern humans from outside of Africa. Analysis

of the genome indicated that the hybridization event resulting in the in-

trogression occurred 50 ky before. The fact that the Ust’-Ishim modern

human had longer tracts of Neanderthal-derived DNA than contempo-

rary populations lends support to the idea that Neanderthal-derived DNA

in modern humans is due to hybridization. Contemporary modern hu-

mans have shorter stretches of Neanderthal-derived genes because there

has been a longer period over which the Neanderthal segments of DNA

could be broken down by recombination.

Thus, there are multiple lines of evidence supporting hybridization be-

Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

Figure 11.13� Phylogeny showing the relationship between modern humans and other hominins over the last 500 kya. This image is also depicting a number of hybridization events—for example, the genetic contributions that Neanderthals and Denisovans made to modern humans around 50 kya.

tween modern humans and

Neanderthals/Denisovans.

This includes shorter di-

vergence times between

introgressed regions in

modern-human and Nean-

derthal sequences, older

modern-human sequences

having longer tracts of Ne-

anderthal-derived genes

and, as discussed below,

the sequencing of con-

�rmed hybrids.

Con�rmed Fossil Hybrids

When discussing hybrids, there are some important terms to understand.

A �rst-generation hybrid is called an F1 hybrid; it is the direct offspring of

two lineages that have been evolving independently over an extended pe-

riod. A second-generation hybrid (F2) would be the offspring of two F1

hybrids. A backcrossed individual is the result of an F1 or F2 hybrid mat-

ing with an individual from one of the parental populations. An example

of a backcross would be when a Neanderthal-human hybrid produces

offspring with a human; their offspring would be considered a �rst-gen-

eration backcrossed hybrid (B1). Sequencing of aDNA from fossil material

has further con�rmed that hybridization between different hominins has

occurred, supporting the introgression data from recent populations.

The sequencing of Oase 1, a suspected hybrid based on skeletal morphol-

ogy (what the fossil looked like), showed that it had a Neanderthal ances-

tor as recently as six to eight generations back. He would thus be consid-

ered a backcrossed individual. The recent sequencing of a 13-year-old

Denisovan female showed that she was the F1 hybrid offspring of a Nean-

Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

derthal mother (from whom she inherited Neanderthal mtDNA) and a

Denisovan father. She was con�rmed to be an F1 hybrid because approxi-

mately 50% of her genome was derived from a Neanderthal and 50%

from a Denisovan.

These are only two examples of individuals who are con�rmed hybrids.

Many other remains show some indication of gene �ow between

hominins.

Neanderthal- and Denisovan-Derived DNA in Modern Genomes

There is variation in how much of the Neanderthal genome is repre-

sented in the modern human population. Individuals outside of Africa

usually have 1% to 2 % of their genome derived from Neanderthals. Ap-

proximately 30% of the Neanderthal genome is represented in modern

human genomes. Asian populations usually have a higher proportion of

their genome derived from Neanderthals when compared to modern Eu-

ropean populations. Additionally, the sequencing of the Denisovan

genome indicates that they interacted with the ancestors of modern

Oceanic populations. Thus, oceanic populations have around 5% to 6% of

their genome derived from Denisovans. There is also evidence that dif-

ferent Denisovans populations may have contributed to Oceanians and

East Asians. The available Denisovan sequences are more similar to the

Denisovan introgressed genes found in East Asian populations.

Introgressed genes have signatures that allow us to identify them and

differentiate them from parts of the genome that are not introgressed.

Some of the things to look for when determining if a segment of the

genome is introgressed include the following. First, how closely does the

segment you are looking at match the Neanderthal/Denisovan sequence

compared to contemporary modern human sequences from Africa? If the

sequence is more similar to the Neanderthal sequence (i.e., it has less se-

quence differences from the Neanderthal than the African modern hu-

Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

man), it is likely that it is derived from a Neanderthal). Second, what is the

divergence time between the allele and the same allele in a Neanderthal?

If it is shorter than the divergence time between humans and Nean-

derthal, then the gene is most likely introgressed. This is expected be-

cause if the divergence time is after the split between modern humans

and Neanderthals, the most likely explanation for a shorter divergence

time is introgression. An example of this can be seen in Figure 11.14. And,

third and �nally, you need to look at whether the allele is found at higher

frequencies in populations outside of Africa.

Figure 11.14 An illustration of a (b) introgressed region (in yellow) in a modern human genome and how it compares to the same segment in a (c) modern human with no introgression and an (a) Neanderthal sequence.

What Can We Learn about the Process of Hybridization from Ancient DNA?

Ancient DNA has also allowed us to make certain inferences about the

process of hybridization between modern humans and

Neanderthals/Denisovans. From looking at the genomes of modern hu-

mans, we can see that there are regions of the genome with no Nean-

derthal and Denisovan genomic variants. These are known as Nean-

derthal or Denisovan introgression deserts. There are also overlaps be-

tween regions in the human genome that are Neanderthal and Denisovan

deserts, which might indicate that there were genomic incompatibilities

between modern humans and these groups, resulting in those genes be-

ing selected against on the modern human genome background. This re- Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

sulted in strong negative selection against these genomic variants in sub-

sequent generations of hybrids and backcrossed individuals.

We can also infer that hybridization may itself have been a barrier to

gene �ow because there is a signi�cant reduction in introgression on the

X chromosome compared to the other chromosomes. There is also a re-

duction of introgressed genes around genes that are disproportionately

expressed in the testes when compared to other tissue groups. This

could indicate that hybridization between modern humans and Nean-

derthals may have resulted in male hybrid infertility.

Hybridization and Modern Human Evolution

Hybridization provided adaptive advantage to modern humans migrating

out of Africa by providing them with advantages in genetic variation. Ne-

anderthals and Denisovans had spent hundreds of thousands of years

adapting to the European and Asian environments and thus had genetic

variants favorable for inhabiting those regions. Through hybridization,

humans were able to acquire favorable genomic variants already selected

for, and these variants could rapidly spread through the population. This

allowed for faster adaptation because acquiring new variation through

mutation alone is much slower and less likely to spread through the pop-

ulation. Some of the adaptive genes that were important include genes

associated with immunity, adapting to new diets, adapting to new alti-

tudes as well as genes involved in skin color and hair traits were intro-

gressed. An excellent example of this would be a variant of the EPAS1

gene found at high frequencies in Tibetans, thought to be important for

living at high altitudes. This variant of EPAS1 has been shown to be an in-

trogressed gene from Denisovans.

�e Future of Genetic Studies Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

We are continuing to learn how introgressed genes affect modern hu-

mans. Combining phenotypic and genetic information Neanderthal de-

rived genes have been associated with diverse traits such as the skin’s

sensitivity to the sun to excessive blood clotting by certain individuals.

Interesting research has also shown that introgressed alleles might pro-

duce different gene expression pro�les when compared to non-intro-

gressed alleles. However, there is a lot of research that needs to be done

to fully understand the effects of introgression on modern populations

and how it might have assisted modern humans who migrated out of

Africa.

It has also been possible to extract DNA from sediments. However, ex-

tractions from sediments will result in extraction of DNA from multiple

organisms. To extract the hominin sequences, we will need to use the

known sequence information. Known sequences will also assist with dif-

ferentiating between which hominins are represented in the sediment.

This could assist with identifying changes in populations across time. The

availability of more Neanderthal and Denisovan samples will also help us

understand which genetic changes were �xed and de�ned these

populations.

HOW DO THESE FIT IN? HOMO NALEDI AND HOMO FLORESIENSIS

Relatively recently, some fossils have been unearthed that have signi�cantly chal-

lenged our understanding of the hominin lineage. The fossils of Homo naledi and

Homo �oresiensis are signi�cant for several reasons but are mostly known for how

they don’t �t the previously held patterns of hominin evolution. We’ll examine

present information about both of these fossils, and we ask that you consider the

wealth of evidence presented in this chapter and in others to draw your own con- Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

Figure 11.15 A sample of some of the 1,550 bones found representing Homo naledi.

clusions regarding the signi�cance and placement of these two unusual fossil

species in the hominin lineage.

Homo naledi

Found in 2013 by recreational

spelunkers, a collection of bones

was uncovered in a deep cave

network in Johannesburg, South

Africa. The cave system, known

as Rising Star, had been well doc-

umented by other cavers; how-

ever, it appears few people had

ever gone as far into the cave as

these spelunkers had. Lee Berger,

paleoanthropologist at University

of Witwatersrand, in Johannes-

burg, immediately put out a call

for what he termed “under-

ground astronauts” to begin re-

covery and excavation of the fos-

sil materials. Unlike other exca-

vations, Berger and most other

paleoanthropologists would not

be able to access the site, as it

was incredibly dif�cult to reach, and at some points there was only eight inches of

space through which to navigate. The underground astronauts, all petite, slender fe-

male anthropologists, were the only ones who were able to access this remarkable

site. Armed with small excavation tools and a video camera, which streamed the

footage up to the surface, the team worked together and uncovered a total of 1,550

bones, representing at least 15 individuals, as seen in Figure 11.15. Later, an additional

131 bones, including an almost-complete cranium, were found in a nearby chamber

of the cave, representing three more individuals (Figure 11.16). Berger called in a

team of specialists to participate in what was dubbed “Paleoanthropology Summer

Previous: Early Members of the Genus Homo

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Camp.” Each researcher specialized in a different portion of the hominin skeleton.

With various specialists working simultaneously, more rapid analysis was possible of

Homo naledi than most fossil discoveries.

The features of Homo naledi are well-documented due to the fairly large sample,

which represents individuals of all sexes and a wide range of ages. The skull shape

and features are very much like other members of the genus Homo, including fea-

tures such as a sagittal keel and large brow, like Homo erectus, and a well-developed

frontal lobe, similar to modern humans, yet the brain size is signi�cantly smaller

than its counterparts, at approximately 500 cc (560 cc for males and 465 cc for fe-

males). The teeth also exhibit features of later members of the genus Homo, such as

Neanderthals, including a reduction in overall tooth size. Homo naledi also had

unique shoulder anatomy and curved �ngers, indicating similarities to tree-dwelling

primates, which is very different from any other hominin yet found. The date on the

species, which was obtained some time after the fossils were �rst analyzed, indi-

cates that Homo naledi lived between 335,000 and 236,000 years ago. This has been

perhaps the greatest shock of all about Homo naledi, as this places this fossil as a

contemporary to modern Homo sapiens, despite the very primitive features it

retains.

Previous: Early Members of the Genus Homo

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Figure 11.16 Several angles of the nearly complete LES1 Homo naledi skull. The skull shape and features are very much like other members of the genus Homo, including features such as a sagittal keel and large brow like Homo erectus and a well- developed frontal lobe, similar to modern humans. The brain size, however, is signi�cantly smaller than its counterparts, at approximately 500 cc.

Other remarkable aspects of the �nd is the placement of the Homo naledi fossils and

what it may suggest. To access the site, approximately 80 m from any known cave

entrance or opening, a treacherous route would have had to have been taken—in-

cluding moving through a portion that is just 25 cm wide at some points, known as

“Superman’s Crawl.” The only way to get through this section is by crawling on your

stomach with one arm by your side and the other raised above your head. Past

Superman’s Crawl, a jagged wall known as the Dragon’s Back would have been very

dif�cult to traverse. Below that, a narrow vertical chute would have eventually led

down to the area where the fossils were discovered. While geology changes over

time and the cave system likely has undergone its fair share, it is not likely that these

dif�cult features arose after Homo naledi lived. This has made scientists curious as

to how the bones ended up in the bottom of the cave system in the �rst place. It has

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been suggested that Homo naledi deposited the bones there, one way or another.

Another competing idea is that a few individuals may have entered the cave system

to escape a predator and then got stuck. To account for the sheer number of fossils,

this would have had to happen multiple times. In contrast, if Homo naledi did deposit

the bones, either through random disposal or intentional burial, this calls into ques-

tion their symbolic behavior and other cultural traits, including the use of �re, to ac-

cess a very dark cave system.

Homo �oresiensis

Figure 11.17 Liang Bua Cave on the island of Flores, in Indonesia, where a collection of Homo �oresiensis specimens were discovered.

In a small cave called Liang Bua, on the island of Flores, in Indonesia, a small collec-

tion of fossils were discovered beginning in 2003 (Figure 11.17). The fossil fragments

represent as many as nine individuals, including a nearly complete female skeleton.

The features of the skull are very similar to that of Homo erectus, including the pres-

ence of a sagittal keel, an arching brow ridges and nuchal torus, and the lack of a

chin (Figure 11.18). Homo �oresiensis, as the new species is called, had a brain size

that was remarkably small at 400 cc, and recent genetic studies suggest a common

Previous: Early Members of the Genus Homo

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Figure 11.18 Homo �oresiensis had a brain that was remarkably small at 400 cc. Recent genetic studies suggest a common ancestor with modern humans that predates Homo erectus.

Figure 11.19 A reconstructed comparison between an anatomically modern human and Homo �oresiensis. As an adult, Homo �oresiensis was approximately 1 meter tall and would have weighed under 30 kg.

ancestor with modern humans that predates Homo erec-

tus.

The complete female

skeleton, who was an adult,

was approximately a meter

tall and would have

weighed just under 30 kg,

which is signi�cantly

shorter and just a few kilo-

grams more than the aver-

age, modern young ele-

mentary-aged child. A re-

constructed comparison

between an anatomically

modern human and Homo �oresiensis can be seen in

Figure 11.19. The small size of the fossil has earned the

species the nickname “the Hobbit.” Many questions

have been asked about the stature of this species, as all

of the specimens found also show evidence of diminu-

tive stature and small brain size. Some explanations in-

clude pathology; however, this seems increasingly unlikely as all fossils found thus

far demonstrate the same pattern. Another possible explanation lies in a biological

phenomena seen in other animal species also found on the island and which date to

a similar time period. This phenomenon, called insular dwar�ng, is due to limited

food resources on an island, which can create a selective pressure for large-bodied

species to be selected for smaller size, as an island would not have been able to sup-

port their larger-bodied cousins for a long period of time. This phenomenon is the

cause of other unique species known to have lived on the island at the same time,

including the miniature stegadon, a dwarf elephant species.

Homo �oresiensis fossils have been dated to have lived on the island between

100,000 and at least 60,000 years ago. There is ongoing research and debate regard-

ing Homo �oresiensis’ dates of existence, with some researchers concluding that

they lived on Flores until perhaps as recently as 17,000 years ago. Stone tools were

also uncovered that have dates overlapping with those of the site and are similar in Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

nature to other hominin stone tools found on the island of Flores. Homo �oresiensis

would have hunted a wide range of animals, including the miniature stegadon, giant

rats, and other large rodents. Other animals on the island that could have threat-

ened them include the giant komodo dragon. An interesting note about this island

chain is that ancestors of Homo �oresiensis would have had to access the open

ocean in order to get there, as the nearest island is almost 10 km away, and there is

little evidence to support that a land bridge connecting mainland Asia or Australia to

the island would have been present. This would also have limited the number of

other animals, including predators as well as human species, that would have had

access to the island. Anatomically modern Homo sapiens arrived on the island

around 30,000 years ago and may have lived there at the same time as Homo �ore-

siensis, if some researchers’ later dates for Homo �oresiensis’ occupation are correct.

The modern population living on the island of Flores today believes that their ances-

tors came from the Liang Bua cave; however, recent genetic studies have deter-

mined they are not related to the Homo �oresiensis species.

Homo naledi and Homo �oresiensis are clear outliers when compared to their con-

temporary hominin species. Each has surprised paleoanthropologists for both their

archaic traits in relatively modern times and their unique combination of traits seen

in archaic species and modern species of humans. While these �nds have been ex-

citing, they have also completely upended the assumed trajectory of the human lin-

eage, causing scientists to re-examine their previously held assumptions about ho-

minin evolution and what it means to be modern. Add this to the developments be-

ing made using ancient DNA, other new fossil discoveries, and other innovations in

paleoanthropology, and you see that our understanding of archaic Homo sapiens and

others living during this time period is rapidly developing and changing. This is a

true testament to the nature of science and the scienti�c method!

FOSSIL SPECIES SUMMARIES

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Hominin archaic Homo sapiens

Dates 600,000–200,000 years ago (although some regional variation)

Region(s) Africa, Europe, and Asia

Famous discoveries

Broken Hill (Zambia), Atapuerca (Spain)

Brain size 1,200 cc average

Dentition Slightly smaller teeth in back of mouth, larger front teeth

Cranial features

Emerging forehead, wide nasal aperture, midfacial prognathism, no chin, projecting occipital region

Postcranial features

Robust skeleton

Culture Varied regionally, but some continue to use Acheulean handaxe, others adopt Mousterian tool culture

Other Lots of regional variation in this species

Hominin Neanderthals

Dates 150,000–35,000 years ago

Region(s) Western Europe, Middle East, and Western Asia only

Famous discoveries

Shanindar (Iraq), La Chapelle-Aux-Saints (France)

Brian size 1500 cc average

Dentition Retromolar gap

Cranial features

Large brow ridge, midfacial prognathism, large infraorbital foramina, occipital bun

Postcranial features

Robust skeleton with short and stocky body, increased musculature, barrel chest

Culture Mousterian tools often constructed using the Levallois technique

Previous: Early Members of the Genus Homo

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Hominin Denisovans

Dates 100,000–30,000 years ago

Region(s) Siberia

Famous discoveries

Child’s �nger bone and adult molar

Brain size unknown

Dentition unknown

Cranial features

unknown

Postcranial features

unknown

Culture unknown

Other Closely related to Neanderthals (genetically)

Species Homo naledi

Dates 335,000-235,000 years ago

Region(s) South Africa

Famous Discoveries

Rising Star Cave

Brain size 500 cc average

Dentition Reduced tooth size

Cranial features

Sagittal keel, large brow, well-developed frontal region

Postcranial features

unknown

Culture unknown

Previous: Early Members of the Genus Homo

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Species Homo �oresiensis

Dates 100,000–60,000 years ago, perhaps as recently as 17,000 years ago

Region(s)  Lingua Bua, island of Flores, Indonesia

Famous discoveries

“The Hobbit”

Brian size 400 cc average

Dentition unknown

Cranial features

Sagittal keel, arching brow ridges, nuchal torus, no chin

Postcranial features

Very short stature (approximately 3.5 ft.)

Culture Similar to other tools found on the island of Flores

Review �uestions

What physical and cultural features are unique to archaic Homo

sapiens? How are archaic Homo sapiens different in both physical

and cultural characteristics from Homo erectus?

Describe the speci�c changes to the brain and skull �rst seen in ar-

chaic Homo sapiens. Why does the shape of the skull change so

dramatically from Homo erectus?

What role did the shifting environment play in the adaptation of ar-

chaic Homo sapiens, including Neanderthals? Discuss at least one

physical feature and one cultural feature that would have assisted

these groups in surviving the changing environment.

In your opinion, which of the hypotheses concerning the disap-

pearance of the Neanderthals best incorporates the available evi-

dence? Why? Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

What does the regional variation in archaic Homo sapiens represent

in terms of the broader story of our species’ evolution?

Describe the issues raised by the discoveries of Homo naledi and

Homo �oresiensis in the understanding of the story of the evolution

of Homo sapiens.

Key Terms

5 prime end: A nucleic acid strand that terminates at the chemical group attached

to the �fth carbon in the sugar-ring.

3 prime end: A nucleic acid strand that terminates at the hydroxyl (-OH) chemical

group attached to the third carbon in the sugar-ring.

Allele: Each of two or more alternative forms of a gene that arise by mutation and

are found at the same place on a chromosome.

Anthropocentrism: A way of thinking that assumes humans are the most important

species and leads to interpreting the world always through a human lens. Species-

centric science and thought.

Coalescent methods: These are models which allow for inference of how genetic

variants sampled from a population may have originated from a common ancestor

Cortex: The outside, or rough outer covering, of a rock. Usually the cortex is re-

moved during the process of stone tool creation.

Deamination: The chemical process that results in the conversion of Cytosine to

uracil, which results in Cytosine to Thymine conversions during sequencing.

Divergence time: A measure of how long two genomic sequences have been chang-

ing independently.

Endogenous aDNA: A form of ancient DNA in which DNA originates from the speci-

Previous: Early Members of the Genus Homo

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men being examined.

Ethnocentric: Applying negative judgments to other cultures based on comparison

to one’s own.

Exogenous DNA: DNA that originates from sources outside of the specimen you are

trying to sequence.

Flexed position: Fetal position, in which the legs are drawn up to the middle of the

body and the arms are drawn toward the body center. Intentional burials are often

found in the �exed body position.

Foraminifera: Microscopic single-celled organisms with a shell that are common in

all marine environments. The fossil record of foraminifera extends back well over

500 million years.

Glaciation: A glacial period, or time when a large portion of the world is covered by

glaciers and ice sheets.

Globular: Round-shaped, like a globe.

Grave goods: Items included with a body at burial. Items may signify occupation or

hobbies, social status, or level of importance in the community, or they may be

items believed necessary for the afterlife.

Haft: A handle. Also used as a verb—to attach a handle to an item, such as a stone

tool.

Haplotype: A set of genetic variants located on a single stretch of the genome. This

unique combination of variants on a stretch of the genome can be used to differenti-

ate groups that will have different combinations of variants.

Heterozygosity: A measure of how many genes within a diploid genome are made up

of more than one variant for a gene.

High-coverage sequences: These are genomic sequences which have been se-

quenced multiple times to ensure that the sequence produced is a true re�ection of

the genomic sequence, and reduce the likelihood that the sequence has sequencing

errors as a result of the the sequencing process. Previous: Early Members of the Genus Homo

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Homozygosity: A measure of how many genes within a diploid genome are made up

of more than the same variant for a gene.

Ice core: A colundular sample of ice that is removed from an ice sheet. The annual

buildup of snow and ice can be studied and interpreted to better understand climate

change, as well as local environmental shifts.

Infraorbital foramina: Small holes on the maxilla bone of the face that allows nerves

and blood to reach the skin.

Insular dwar�ng: A form of dwar�sm that occurs when a limited geographic region,

such as an island, causes a large-bodied animal to be selected for a smaller body

size.

Interglacial: A warmer period between two glacial time periods.

Introgressed genes: This is the movement of genes from one species to the gene

pool of another species through hybridization between the species and backcross

into the parental population by hybrid offspring.

Levallois technique: A distinctive technique of stone tool manufacturing used by ar-

chaic Homo sapiens, including Neanderthals. The technique involves the preparation

of a core and striking edges off in a regular fashion around the core. Then a series of

similarly sized pieces can be removed, which can then be turned into different tools.

Midfacial prognathism: A forward projection of the nose, or middle facial region.

Usually associated with Neanderthals.

Mousterian tools: The stone tool industry of Neanderthals and their contempo-

raries in Africa and Western Asia. Mousterian tools are known for a diverse set of

�ake tools, which is different than the large bifacial tools of the Acheulean industry.

Nasal aperture: The opening for the nose visible on a skull. Often pear- or heart-

shaped.

Non-synonymous mutations: These are changes that also occur in the protein-cod-

ing region of the genome but don’t result in a change in amino acid sequence of the

protein being produced. Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

Amanda Wolcott Paskey

Occipital bun: A prominent bulge or projection on the back of the skull, speci�cally

the occipital bone. This is a feature present only on Neanderthal skulls.

Ochre: A natural clay pigment mixed with ferric oxide and clay and sand. Ranges in

color from brown to red to orange.

Recombination: This is the process of exchange of DNA between two strands to

produce new sequence arrangements.

Retracted face: A face that is �atter.

Retromolar gap: A space behind the last molar and the end of the jaw. This is a fea-

ture present only on Neanderthals. It also occurs through cultural modi�cation in

modern humans who have had their third molars, or wisdom teeth, removed.

Sediment core: A colundular sample of soil and sediments that can be analyzed to

study plant and animal presence in a location, or more broadly to determine a re-

gional environment.

Synonymous mutations: Mutations that occur in the protein-coding region of the

genome and result in a change in the amino acid sequence of the protein produced.

About the Authors

Amanda Wolcott Paskey

Amanda Wolcott Paskey is an anthropology professor at Cosumnes

River College in Sacramento, California. She earned her B.A. and

M.A. in anthropology from the University of California, Davis. Her

speciality in anthropology is archaeology; however, she was trained

in a holistic program and most of her teaching load is in biological

anthropology. She is currently working on analyzing a post–gold

rush era archaeological site, in Sacramento, with colleagues and

students. This project has given her many opportunities to engage

Previous: Early Members of the Genus Homo

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AnneMarie Beasley Cisneros

Robyn Humphreys

in sharing archaeology with a public audience, including local school children and

Sacramentans interested in local history.

AnneMarie Beasley Cisneros

AnneMarie Beasley Cisneros is an anthropology professor at Amer-

ican River College in Sacramento, California. Trained as a four-�eld

anthropologist, she earned her B.A. and M.A. in anthropology from

California State University, Sacramento. She regularly teaches bio-

logical anthropology, among other courses, and is currently en-

gaged in applied anthropology work in community development

with historically underserved communities. She most recently has

particularly enjoyed facilitating her students’ involvement in

projects serving Sacramento’s Latino and immigrant Mexican

populations.

About the Special Topic: Ancient DNA Author

Robyn Humphreys is a biological anthropologist based in the ar-

chaeology department at the University of Cape Town. Her MSc

focused on the role of hybridization in human evolution. She is

now pursuing her Ph.D., which will involve looking at the rela-

tionship between archaeologists and communities in relation to

research on human remains from historical sites in Cape Town.

For Further Exploration Previous: Early Members of the Genus Homo Next: Modern Homo sapiens

Anne and Bernard Spitzer Hall of Human Origins—American Museum of Natural His-

tory https://www.amnh.org/exhibitions/permanent-exhibitions/anne-and-

bernard-spitzer-hall-of-human-origins

“Dawn of Humanity,” PBS documentary, 2015

“DNA Clues to Our Inner Neanderthal,” TED Talk by Svante Pääbo, 2011.

https://www.ted.com/talks/svante_paeaebo_dna_clues_to_our_inner_neande

rthal?language=en

“The Dirt” Podcast, Episode 30 “The Human Family Tree (Shrub? Crabgrass? Tum-

bleweed?), Part 3� Very Humany Indeed”

https://thedirtpod.com/episodes//episode-30-the-human-family-tree-shrub-

crabgrass-tumbleweed-part-3

E Fossil games and activities http://www.efossils.org/page/games-and-activities

“Hobbits on Flores, Indonesia” Smithsonian Human Origins

http://humanorigins.si.edu/research/asian-research-projects/hobbits-�ores-

indonesia

Shanindar 3—Neanderthal Skeleton—Smithsonian Human Origins

http://humanorigins.si.edu/evidence/human-fossils/shanidar-3-neanderthal-

skeleton

Smithsonian’s Human Origins Program Facebook page (@smithsonian.humanorigins)

https://www.facebook.com/smithsonian.humanorigins/

Paleoartist Brings Human Evolution to Life—Elisabeth Daynés

https://www.smithsonianmag.com/science-nature/bringing-human-evolution-

life-180951155/

Green, R. E., J. Krause, A. W. Briggs, T. Maricic, U. Stenzel, M. Kircher, et al. 2010. “A

Draft Sequence of the Neanderthal Genome.” Science 328 (5979): 710–722.

Gibbons, A. 2014. “Neanderthals and Moderns Made Imperfect Mates.” Science 343

(6170): 471–472. doi: 10.1126/science.343.6170.471.

Huerta-Sánchez, E., X. Jin, Z. Bianba, B. M. Peter, N. Vinckenbosch, Y. Liang, et al. Previous: Early Members of the Genus Homo

Next: Modern Homo sapiens

2014. Altitude Adaptation in Tibetans Caused by Introgression of Denisovan-like

DNA. Nature 512 (7513): 194.

Jeong, C., G. Alkorta-Aranburu, B. Basnyat, M. Neupane, D. B. Witonsky, J. K.

Pritchard, C. M. Beatl, and A. Di Rienzo. 2014. “Admixture Facilitates Genetic Adap-

tations to High Altitude in Tibet.” Nature Communications 5� 3281. doi:

10.1038/ncomms4281

Krings, M., A. Stone, R. W. Schmitz, H. Krainitzki, M. Stoneking, and S. Pääbo. 1997.

“Neanderthal DNA Sequences and the Origin of Modern Humans.” Cell 90 (1): 19–

30.

Krouse, J., Q. Fu, J. M. Good, B. Viola, M. V. Shunkov, A. P. Derevianko, and S. Pääbo.

2010. “The Complete Mitochondrial DNA Genome of an Unknown Hominin from

Southern Siberia.” Nature 464� 894–897.

Prüfer, K., F. Racimo, N. Patterson, F. Jay, S. Sankararaman, S. Sawyer, et al. 2014.

“The Complete Genome Sequence of a Neanderthal from the Altai Mountains.” Na-

ture 505 (7481): 43-49.

Racimo, F., S. Sankararaman, R. Nielsen, and E. Huerta-Sánchez. 2015. Evidence for

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Sankararaman, Sriram, et al. “The genomic landscape of Neanderthal ancestry in

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Vernot, B., S. Tucci, J. Kelso, J. G. Schraiber, A. B. Wolf, R. M. Gittelman, et al. 2016.

“Excavating Neanderthal and Denisovan DNA from the Genomes of Melanesian In-

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Acknowledgments

The authors would like to extend their thanks to Cassandra Gilmore and Anna Gold-

�eld for thoughtful and insightful suggestions on this chapter. Previous: Early Members of the Genus Homo

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Figure Attributions

Figure 11.1 Big head primitive caveman nose man bone cave at Max Pixel has been

designated to the public domain (CC0).

Figure 11.2 All paleotemps by Glen Fergus is used under a CC BY-SA 3.0 License.

Figure 11.3 Homo erectus, archaic Homo sapiens, and anatomically modern Homo

sapiens table original to Explorations: An Open Invitation to Biological Anthropology

is under a CC BY-NC 4.0 License.

Figure 11.4 Homo heidelbergensis Cranium Broken Hill 1 (Rhodesian Man) by

©BoneClones is used by permission and available here under a CC BY-NC 4.0 Li-

cense.

Figure 11.5 Homo heidelbergensis Skull Atapuerca 5 by ©BoneClones is used by per-

mission and available here under a CC BY-NC 4.0 License.

Figure 11.6 Neanderthal distinguishing features table original to Explorations: An

Open Invitation to Biological Anthropology is under a CC BY-NC 4.0 License.

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and available here under a CC BY-NC 4.0 License.

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a CC BY-SA 2.5 License,

Figure 11.9 NHM – Levalloiskern by Wolfgang Sauber is used under a CC BY-SA 4.0

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Figure 11.10a Homo neanderthalensis Shanidar 1 Skull by ©BoneClones is used by

permission and available here under a CC BY-NC 4.0 License.

Figure 11.10b Shanidar 1 by Smithsonian [exhibit: Human Evolution Evidence, Human

Fossils, Species, Homo neanderthalensis] is copyrighted and used for educational and

non-commercial purposes as outlined by the Smithsonian.

Figure 11.11 Neandertala homo, modelo en Neand-muzeo (image was taken in the Ne- Previous: Early Members of the Genus Homo

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Explorations by Beth Shook, Katie

Nelson, Kelsie Aguilera, and Lara Braff,

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anderthal Museum, Mettmann, Germany) by UNiesert is used under a CC BY-SA 3.0

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Figure 11.12 DNA extraction by Robyn Humphreys original to Explorations: An Open

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Figure 11.13 Homo sapiens lineage by Dbachmann is used under a CC BY-SA 4.0 Li-

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Figure 11.14 Introgressed Neanderthal DNA in a modern human genome by Robyn

Humphreys original to Explorations: An Open Invitation to Biological Anthropology

is under a CC BY-NC 4.0 License.

Figure 11.15 Dinaledi skeletal specimens (Figure 1) by Berger, Lee R. et al. 2015. “Homo

naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa.”

eLife 2015;4�e09560 (DOI: 10.7554/eLife.09560) is used under a CC BY 4.0 License.

Figure 11.16 LES1 Cranium (Figure 5) by Hawks et al. 2017. “New fossil remains of

Homo naledi from the Lesedi Chamber, South Africa”. eLife 2017;6�e24232.

(DOI�10.7554/eLife.24232) is used under a CC BY 4.0 License.

Figure 11.17 Homo �oresiensis cave by Rosino is used under a CC BY-SA 2.0 License.

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Figure 11.19 Anatomically modern human and Homo �oresiensis reconstruction origi-

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