Chapter 6

1. Chapter 6 Primate Behavior

2. Chapter Outline • Importance of Primate Study • Evolution of Behavior • Nonhuman Primate Social Behavior • Reproduction and Reproductive Strategies • Mothers and Infants • Nonhuman Primate Cultural Behavior • Primate Cognitive Abilities • The Primate Continuum

3. Importance of Primate Studies • Modern African apes and humans last shared a common ancestor between 5 and 8 m.y.a. • Only within the last 4 decades have nonhuman primates been studied. • Many species, such as arboreal monkeys have scarcely been studied at all.

4. Primate Socioecology • Socioecology studies the relationship between social behavior and the natural environment. • One assumption is that components of ecological systems evolved together. • To understand how one component works, it is necessary to determine the species relationships with their environment.

5. Environmental Factors • Quality and quantity of foods • Distribution of food resources, water, predators and sleeping sites • Activity patterns (diurnal, nocturnal) • Relationship with other species • Impact of human activities

6. Socioecology and Predation • Multimale and multifemale groups have an advantage when predation pressure is high. • Adult males may join forces to attack predators. • Savannah baboons have been known to kill domestic dogs and attack leopards and lions. • Solitary foraging may be due to diet and distribution of resources or predator avoidance.

7. Evolutionary Perspective • Natural selection acts on behavior just as it acts on physical characteristics. • Behavior is a phenotypic expression and genes code for specific behaviors. • Natural selection has a role in shaping primate behavior.

8. Criticism of the Evolutionary Perspective Little data on: • The social behavior of large groups of animals. • Genetic relatedness through the male line. • Assigning reproductive costs and benefits to particular behaviors. • The genetics of primate social behavior.

9. Dominance Status • Factors that influence status: • Sex • Age • Aggression • Time in the group • Intelligence • Motivation • Mother’s social position

10. Communication • Raised body hair is an example of an autonomic response. • Vocalizations and branch shaking are examples of deliberate communication. • Reassurance is communicated through hugging or holding hands. • The fear grin, seen in all primates, indicates fear and submission. • Displays communicate emotional states.

11. Aggression • Primates might defend a core area within their permanent home. • Jane Goodall witnessed unprovoked, brutal attacks of chimpanzees by other chimpanzees. • Territoriality and acquisition of females are the motives suggested for chimpanzee male aggression.

12. Affiliative Behaviors Reinforce bonds between individuals and enhance group stability: • Grooming reinforces social bonds. • Hugging, kissing and grooming are all forms used in reconciliation. • Relationships are crucial to nonhuman primates and the bonds between individuals can last a lifetime. • Altruism, behaviors that benefit another while posing risk to oneself, are common in primate species.

13. Patterns of Reproduction • In most primate societies, sexual behavior is tied to the female’s reproductive cycle. • Permanent bonding is not common among nonhuman primates. • Male and female Bonobos may mate even when the female is not in estrus, a behavior that is not typical of chimpanzees.

14. Reproductive Strategies • Behavioral patterns that contribute to individual reproductive success. • Primates produce only a few young in whom they invest a tremendous amount of parental care. (k –selected) • Male competition for mates and mate choice in females are both examples of sexual selection.

15. Mothers and Infants • The basic social unit among all primates is the female and her infants. • Except in species in which monogamy or polyandry occur, males do not participate in rearing offspring. • Monkeys raised without a mother were not able to form lasting affectional ties. • The mother-infant relationship is often maintained throughout life.

16. Nonhuman Primate Cultural Behavior • Cultural behavior is learned and passed from one generation to the next. • Chimpanzee culture includes tools such as termite fishing sticks and leaf sponges.

17. Primate Cognitive Abilities • Social interactions and problem-solving abilities demonstrate primate intelligence. • Vervet monkeys have three different vocalizations to indicate types of predators. • The fact that apes can’t speak has more to do with their anatomy and the language related structures of the brain than intelligence.

18. The Primate Continuum • Human brains are larger than primate brains, but the neurological processes are functionally the same. • That humans are part of an evolutionary continuum is the basis for animal research, yet we cage nonhuman primates without regard for their needs. • Nonhuman primates should be maintained in social groups and introduced to habitat enrichment programs.