Primate Behavior

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As you work through this set of chapter slides, keep in mind the notations that are included from your instructor. Open, read carefully, download if necessary, and use in conjunction with your reading and video lesson study. All these components supplement each other. The wise student will keep this in mind.

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Why bother? Well, not only are the non human primates down-right interesting but we are very closely genetically related to them, especially to some in particular, as you shall learn.

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There are three main ways to go about primate study, some more desirable than others: field study; provisioned colonies/semi-free-range study; zoo/lab/Captive study [Habituation occurs in all scenarios to one degree or another]

* Zoo/Lab or “Captive Studies”: primates may also be studied in zoos or in laboratories.

 

Question: What becomes of “research chimps”? What about the “movie stars”? “Disposal” of left-overs! Lock up! Mistreatment.

 

* Provisioned Colonies/semi-free-range environments: Such as national parks or captive island scenario. It is not always possible or practical [cost/time] to conduct a field study, so this method becomes an alternative.

Short-comings: The influence of visitors on animals.

* Field Study: There, the natural behavior of the animal can be observed in its own habitat, where behavior is “un-staged” and is a result of its own instinctive interaction with its environment--Jane Goodall (chimps) & Dianne Fossey (Lowland gorilla).

 

Short comings of early field studies...a week or more! Doctoral candidates today...extensive fieldwork required

Other drawbacks today can be funding availability, visibility/invisibility of animals, etc.

 Conclusion: Looking on the bright side, each method can supplement the other.

 

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Proximate (immediate) influences on evolution of primate social behavior may be:

One more immediate influence is hunger, which may trigger fission or fusion; or predatory neighbors may call for large groupings & thus elaborate “rules” of behavior...keep quiet on border patrol...use of sentries.

Deep-seated influences may be hormonal or physiological...estrus (gives rise to competition,) or dimorphism (big boys hang out in groups); all this definitely influences behavior and sets up patterns over time.

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Social Relationships Chimp social order involves a lot of “dominance” & “submission” male-to-male, female-to- female; and also male-to-female. Filopatry...what’s this?

With female filopatry...she stays “home” and he moves out (e.g., the Savanna baboon). There’s a strong incentive for the females to cooperate for resources or to limit competition (food, sleeping space, etc.)

Male filopatry means that whereas the young female migrates to new community, the mature young male “stays home” (p.179-80). And since males remain “home”, they tend to develop close relationships, even spending a lot of time grooming each other. This “arrangement” results in female vulnerability.

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Take the Chimp as example here.

 

* Dominance is established early in life.

In this dominance hierarchy, young male will establish himself by sexually dominating as many females as possible; then, he works up the ladder among his fellow males.

 

* Displacement occurs when junior member relinquishes seat in favor of senior member; may even present (offer) butt to senior male, who may mount him. (A similar system is found among females.) Among H. sapiens, RAPE = power! In prison...well, use your imagination.

 

However, male dominance not true of all primate species (Lemur female is boss & makes it known! p.181).

Female Reproductive Strategies include:

Dominance: Hey! She doesn’t mate with the male “winner” in a fight for sexual access. How come?

Female CHOOSES! She invests a lot of time and energy in...

Gestation is longer for primates than for other animals; Lactation, access to food resources; does he control some?

Raising the young, which are utterly dependent on Mom! He’d better father healthy offspring; don’t waste mom’s time!

While NOT as important as for males, dominance & rank is evident in a particular female’s ability to attract healthy suitors, not to mention her daughters’ ability to achieve “favored” status. Mother’s influence does count! And she DOES manipulate the males...How so?

 

* Estrus/sexual receptivity signals may be:

Behavioral: body posture, mating dance, present rump offering!

Anatomical: sexual swelling can be a “come on” to incite competition among males. Confuses paternity!

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Why are Nonhuman Primates Social?

• The Paradox of Sociality

• Access to Mates
• Food
• Avoiding Predators

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• Types of Nonhuman Primate Societies
• Solitary
• Monogamy
• Polygyny
• One-male
• Multimale
• Fission-Fusion Polygyny
• Polyandry

Why are Nonhuman Primates Social? (cont’d)

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