Graphical summary

Primate Social Behavior 2

Anthropology 2200

Non-residential pattern aspects primate behavior

• Competition • Cooperation • Culture • Parenting behaviors • Tool use • Language

Social Strategies

Male Competition

• Male reproductive strategy  competition for mates

• Produce lots of offspring • Prevent other males from doing

the same thing • Intimidation • Fighting • Leads to sexual selection

• Body size / canine dimorphism

Mandrill: Coloration = health Tooth size

Uakari: Color = health and dominance

Male Competition

• Sperm competition

• Relationship between:

• Testes size

• Penis size

• More competition = larger size

Female Competition

• Female reproductive strategy  competition for resources

• Ensure the survival of offspring

• Dominance relationships • Access to resources

Female Baboon hierarchy

Competition

• Aggressive behaviors • Direct eye contact • Raising eyebrows • Baring canines • Charging

Gelada Baboons

Competition

• Subordination • Ritualized behavior

• Showing backside • Cowering • Presenting to groom • Greeting with friendly facial

expressions and vocalizations

• Intended to ease tension • Prevent conflict

Unequal Pay – Primate Jealousy

• Differences in food quality • Personal jealousy?

Capuchin monkeys and equity

Cooperation

• Affiliative behaviors • Promote group

cohesion • Assurance • Pleasure • Reciprocity

Cooperation

• Form of Altruism • Behavior that benefits others while being a

disadvantage to the individual • Grooming/playing • Hunting/Food sharing • Caregiving • Attacking predators • Giving warning calls

• Kin selection • Behavior that increases the fitness of those

closely related to the individual • Usually the focus of altruistic behavior • Increases the donor’s inclusive fitness

• Reproductive success of organism and close kin

Cooperation

• Grooming to remove parasites and dead skin

• Maintains close contact between family members and non-related group members

• Eases tension • Promotes group cohesion

Chimpanzee grooming

Cooperation

• Playing • Maintains close contact between family

members and non-related group members • Eases tension • Promotes group cohesion

Bonobos Playing

Cooperation

• Caring for young that are not yours • Alloparenting

• Individual other than parent cares for the infant

• Usually done by females (in some species, males also contribute)

Capuchin Monkey

Squirrel Monkey

Cooperation

• Attacking predators and giving warning calls • Allows other members of the group to

escape

• Might lead to injury or death

Vervet Monkey did not survive….

Baboon did survive

Cooperation

• Group Hunting/Foraging • Find food more efficiently • Might find food/hunt prey that you

could not get as an individual • Have to share • Might get injured during hunt

Chimpanzee hunting

Cooperation

• Warfare • Observed in chimps • Group fights between chimps over

territory • Often kill neighboring males • Territory = access to food resources

Chimpanzee patrol composed of primarily

males

Chimpanzee raids

Chimpanzee politics

So where do these behaviors come from? Parenting

• Prolonged period of development • Prolonged period of parental care • Allows parents to teach offspring how to succeed

socially/in environment • Parents VERY important!

Parenting • 1950s psychological experiments (Harry Harlow)

• Demonstrated parenting = not just nourishment • Monkey’s taken from mothers shortly after birth • Raised alone in cages: wire “nourishing” mother, cloth

mother, no mother • Preferred cloth mother = warmth, comfort, security • No mother = distressed, refused to eat, died

Parenting

• Specifics – what do primates learn from their parents?

• Non-verbal and verbal communication

• Social behavior: competition and cooperation

• Tool use • Parenting behavior • Culture!

How do we know its culture and not just inborn behavior?

• Harlow’s Experiments • Japanese Macaques

• Beach of Koshima • Wash sweet potatoes in salt water • 1 decade idea spread • From very few to most

Japanese macaques

The unique side of bonobos

Culture: Examples • Tool use: Chimpanzees

• Spears and their use for hunting bush babies • Termite fishing • Chewed leaves as sponges • Rocks for breaking open nuts

Chimps spearing

Termite fishing

Culture: Examples

• Chimp grooming traditions • Differ depending on the group

• Gombe National Park, Tanzania • Groom each other by holding an overhead branch with one hand

and grooming a partner with the other • Mahale National Park, Tanzania

• Clasp hands while grooming

Gombe Mahale

Communication

• Voluntary (intentional) • e.g. postures,

vocalizations, and facial expressions

• Autonomic (unintentional)

• e.g. estrus

Voluntary Communication Example: Gorilla

• Sharp grunting: a sign of disapproval. • Chuckling: a sign of playfulness. • Screaming: a sign of alarm or warning. • High-pitched barking: a sign of curiosity. • Roaring: a sign of aggression. • Belching: a sign of contentment

Language

• Significant human development

• Communication in non- human primates:

• Emotional • Only in the present • Predator alarm system • Establish territories

Language

• Non-human primates • Many have been taught ASL

• Don’t have vocal range for human language/no syntax

• Teach others ASL • Can make references to external

objects • E.g. “go get ball outside”

• Can identify images of things in addition to the things themselves

Koko with All Ball

Koko’s sign language