1. Why Study Non-Human Primates?

2. Why Study Non-Human Primates?
1. Behaviors universal among modern primates give us clues to our ancestors’ behavior
2. Allows reconstruction of likely social structure, ecology, and intelligence
3. Compare and contrast primate social organizations, communication, intelligence
4. Better understand the environmental factors that led to the divergence of the human lineage
5. Learn how we can preserve the endangered primates

3. The Evolution of Behavior
Behavior has evolved through natural selection
Individual acts to maximize its own reproductive success
Natural selection acts on behaviors in the same way it acts on physical characteristics
Behavior is the product of complex interactions between genetic and environmental factors

4. Factors That Influence Behavior
Quantity and quality of foods
Spatial distribution of food resources
Distribution and reliability of water supplies
Body size
Distribution and types of predators

5. Comparing Behavior
HOMOLOGIES = Traits shared by 2 or more species through inheritance from a common ancestor
Examples= human arms & bat wings, chimp & bonobo behavior more homologous to humans (diverged 5 mya) v. baboons & humans (diverged 20 mya)
ANALOGIES = Traits shared by 2 or more species that are similar in function but not evolutionarily related
Example= bat and insect wings
The more evolutionarily distant, the less useful the comparison!

6. Factors That Influence Behavior
Distribution and types of sleeping sites
Activity patterns
Relationships with other nonpredator species
Impact of human activities

7. Nonhuman Primate Behavior: Dominance
Most primate societies are organized into dominance hierarchies
Reduces the amount of actual physical violence
Dominant animals can often exert control with only a gesture

8. Dominance
The relative hierarchical position of an individual in a social group
Maintains group order by determining who gets what, when
Measured by looking at access to limited resources, interactions between individuals
Influenced by: age, sex, personality, amount of time in the group, intelligence, mother’s status, number of relatives in the group
Status is learned

9. Nonhuman Primate Behavior Communication
Transmission of information by sensory means
Scents, facial expressions and displays, gestures, postures, vocalizations
Displays--sequences of repetitious behaviors that communicate emotional states
May be unintentional or intentional
Submissive gestures reduce aggression
Physical contact and grooming reinforce friendly intentions
Used to threaten, invite play or grooming, express dominance, reassure, greet, warn about predators, food

10. Nonhuman Primate Behavior Aggression
Conflict develops out of competition for resources
Most situations are resolved through submissive and appeasement behaviors
Competition for mates frequently results in injury, and occasionally death

11. Nonhuman Primate Behavior Affiliative Behaviors
Physical contact promotes peace in social groups
Grooming reinforces social bonds
Relationships are crucial and bonds between individuals can last a lifetime
Altruism is common among many primate species

12. Affiliative Behaviors
Reconciliation, consolation, and friendly interactions
Based on physical contact (hugging, hand holding, touching, kissing)
Nonhuman primates form alliances: two or more animals join together for a common purpose

13. Play Difficult to define, but you know it when you see it
Occurs most commonly in infants and juveniles
Requires curiosity (intelligence?) and can be dangerous…requires parental vigilance
Functions to build the individual’s mental, social, and physical skills
Time spent in play declines when the individual is stressed (e.g. malnutrition)
Adults also play, but usually is oriented toward parenting responsibilities

14. Nonhuman Primate Behavior Patterns of Reproduction
Females are receptive to males only when they are in estrus
Permanent bonding is not common
Sometimes, mating relationships are formed, temporary relationships that last while the female is in estrus

15. Reproductive Strategies
Estrus--behavioral and physical changes that indicate that a female is ovulating and receptive to copulation
Some primates, including humans, gibbons, and bonobos, mate throughout the female’s cycle and give no obvious signals of ovulation
Influences how the two sexes interact and the species’ mating system

16. Reproductive Strategies
Females spend almost all of their adult lives pregnant, lactating and/or caring for offspring
Males try to secure as many mates as possible to increase genetic contribution to the next generation

17. Mothers and Infants
Basic social unit among primates
Monkeys and apes raised in captivity without contact with their own mothers did not know how to care for infants
Males do not participate greatly in the rearing of offspring

18. Nonhuman Primate Cultural Behaviors
Culture is learned and passed on from one generation to the next
May be learned through instruction (common only for humans) and through observation (common in all primates)
Cultural traditions are behaviors that become common in the entire group
Examples: washing potatoes, tool use, dietary preferences, greeting styles

19. Primate Behavior
Key Terms

20. anthropocentric Viewing nonhuman primates in terms of human experience; emphasizing the importance of humans over everything else
social structure Composition, size and sex distribution of a group of animals
dominance hierarchies Systems of social organization wherein individuals within a group are ranked relative to one another

21. communication Acts that convey information, in the form of a message, to another individual
displays Sequences of repetitive behaviors that serve to communicate emotional states
affiliative Pertaining to amicable relationships between individuals

22. territories Areas aggressively protected by an animal or group of animals
grooming Picking through fur to remove dirt, parasites, and other materials that may be present; common among primates; reinforces social relationships

23. reproductive strategies Behavior patterns that contribute to individual reproductive success
sexual selection Type of natural selection that operates on only one sex within a species
altruism Any behavior or act that benefits another individual but poses some potential risk or cost to oneself (adoption, protecting young, helping another in a fight)

24. Langur: “Takeover” Behavior
One adult male, several adult females, offspring; other males live in “bachelor” groups
Takeovers involve running out the resident male and killing all unweaned infants
Why does this behavior occur?

25. Langur: Old World Monkey (Vietnam, India, Cambodia)

26. Langur: “Takeover” Behavior
Takeover male is attempting to maximize his reproductive success
Causes mother to begin sexual cycle
Enables takeover male to father offspring faster than if he waited 1-2 years for weaning to occur
Male tenure in the group is short--3 years or less