Unit 4 continuedPrimate behavior

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Behavior, ecology, and evolutionBehavior - actions of an organism(s) in response to environmental factors

Ecology - studies the relationship between organism(s) and all aspects of their environment

Behavioral ecology - hypothesis: all of the interconnected biological components of ecosystems have evolved together

Thus, the result of these complex interactions is behavior

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Primate social unitBasic primate social unit: female and her infant(s)

Note: nonhuman primates learn their caregiving behavior-monkeys/apes in captivity without parental contact do not know how to care for newborn infants

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1. Primate grouping patterns1. Single female and offspring - Basic social unit (e.g., orangutans)

2. Monogamous family group - rare in nonhuman primates

3. Polyandrous - single female: multiple male (e.g., marmosets)

4. Single male and multiple female - single male: multiple female (e.g., gorillas)

5. Multiple males and multiple females - no stable bonds (e.g., baboons)

6. Fission-fusion - size and composition change relative to activities and patterns (e.g., chimpanzees)

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Reproductive strategiesBehavior favored by natural selection to increase an individual's reproductive success

K-selection - an adaptive strategy with fewer offspring and increased parental investment

E.g., birds, wolves, elephants

r-selection - more offspring coupled with less parental investment

E.g., mice

Primates are K-selected and the mother plays a larger role in raising offspring

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Primate reproductive strategiesPrimates are K-selected and the mother plays a larger role in raising offspring

Females - strategy: maximize available resources given energetic demands of being female

Males - strategy: produce as many offspring as possible

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3. Primate social behaviorDominance hierarchies

-ranked by access to resources (which can increase reproductive success)

-maintaining dominance hierarchies impose group order because they establish parameters of behavior for individuals

-males usually dominant to females-males have different hierarchies compared to females

Benefits-reduces occurrence of physical violence (usually displays of dominance instead)

In primates: social rank is established/upheld through learning one's position in the hierarchy 7

4. Communication-unique acts conveying information to another individual/group

-used by all nonhuman primates

-vital to social living

Include: facial expressions, displays, vocalizations, interactions

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Aggressive and affiliative behaviorsAggressive-conflicts arise due to competition for resources-dominant females observed harassing lower ranking females-males often exhibit violent behaviors

Affiliative-amicable behavior promoting group cohesion-grooming

Importance of affiliative behavior:-individuals support each other against outsiders-status is often enhanced through alliances

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Grooming

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