Primate Social Behavior How much like us are they? t=FL1BxWs1YRxy93HENnJUBmkw

Some Factors That Influence Social Structure  Activity patterns  Most primates are diurnal, but several small-bodied promisians and the owl monkey are nocturnal  Nocturnal primates tend to forage for food alone or in groups of 2 or 3, and use concealment to avoid predators =FL1BxWs1YRxy93HENnJUBmkw

Group living exposes animals to competition with other group members, so why not live alone?  Costs of competition are offset by the benefits of predator defense provided by associating with others.  Group living evolved as an adaptive response to a number of ecological variables. Why Be Social?

Primate Social Behavior: Dominance  Many primate societies are organized into dominance hierarchies that impose order and establish parameters of individual behavior.  Higher-ranking animals have greater access to preferred food items and mating partners than lower ranking individuals.  Dominance hierarchies are sometimes called “pecking orders” that change throughout one’s life and are learned

Factors that Influence Dominance Status  Sex  Age  Aggression  Time in the group  Intelligence  Motivation  Mother’s social position

Thinking About Humans  How is social stratification similar to and different from the dominance hierarchies found in many primate species?

Primate Social Behavior: Communication Any act that conveys information to another individual. Frequently, the result of communication is a change in the behavior of the recipient. Communication may be the result of involuntary processes or a secondary consequence of an intentional action. list=FL1BxWs1YRxy93HENnJUBmkw

Communication Raised body hair is an example of an autonomic, or unintentional, response. Gestures, facial expressions, and vocalizations are examples of deliberate communication. The fear grin, seen in all primates, indicates fear and submission. Grooming serves to indicate submission or reassurance. Displays communicate emotional states.

Primate Communication An adolescent male savanna baboon threatens the photographer with a “yawn” that shows the canine teeth. The eyes are closed briefly to expose cream-colored eyelids. This has been called the “eyelid flash.”

Chimpanzee Facial Expressions st=FL1BxWs1YRxy93HENnJUBmkw

Primate Social Behavior: Aggressive Interactions Lead to group disruption, as opposed to affiliative behavior, which promote group cohesion. Conflict within a group frequently develops out of competition for resources, including mating partners and food items. Most intragroup aggression occurs in the form of various signals and displays within the context of a dominance hierarchy. Most tense situations are resolved through various submissive and appeasement behaviors.

Serious and Fatal Consequences of Aggression Dominant actions can keep subordinates away from food and using weight loss and poor nutrition, threatening reproductive success of subordinates Competition can result in injury and death ist=FL1BxWs1YRxy93HENnJUBmkw st=FL1BxWs1YRxy93HENnJUBmkw

Intergroup Aggression Primate groups are associated with a home range where they remain permanently. Within the home range is a portion called the core area, which contains the highest concentration of predictable resources, and it’s where the group is most frequently found. The core area can also be said to be a group’s territory, and it’s the portion of the home range defended against intrusion.

Territories Members of a chimpanzee “border patrol” at Gombe survey their territory from a tree. ist=FL1BxWs1YRxy93HENnJUBmkw

Thinking About Humans How are primate aggressive behaviors similar to and different from the violent actions that are present in human societies?

Primate Social Behavior: Affiliation and Altruism Common affiliative behaviors include reconciliation, consolation, and interactions between friends and relatives. Hugging, kissing and grooming are 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.

Grooming Picking through fur to remove dirt, parasites, and other materials that may be present. Social grooming is common among primates and reinforces social relationships.

Reproduction and Reproductive Behaviors In most primate societies, sexual behavior is tied to the female’s reproductive cycle--estrus. Permanent bonding between females and males 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.

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) (contrast r- selected) Male competition for mates and mate choice in females are both examples of sexual selection.

Thinking About Humans How are human marriage practices similar to and different from primate reproductive strategies?

Sexual Selection A type of natural selection that operates on one sex, usually males. Long-term, this increases the frequency of traits that lead to greater success in acquiring mates. Sexual selection in primates is most common in species in which mating is polygynous and male competition for females is prominent. Sexual selection produces dimorphism with regard to a number of traits, most noticeably body size.

Primate Bonding In am experiment, infants raised with no mother were incapable of forming lasting ties. None of the motherless males successfully copulated, and females who were impregnated either paid little attention to or were aggressive toward infants.

Primate Cultural Behavior Cultural behavior is learned; it is passed from generation to generation through observation and instruction. Nonhuman primate infants, through observing their mothers and others, learn about food items, appropriate behaviors, and how to use and modify objects to achieve certain ends. More complex, chimpanzee culture includes tools such as termite fishing sticks and leaf sponges. =FL1BxWs1YRxy93HENnJUBmkw

Examples of Cultural Behavior Japanese macaques and sweet potato washing Orangutan nest building Gorilla depth desting Chimpanzee termite fishing, leaf sponges, hunting “spears,” nut cracking Kanzi’s stone tool making

Anthropocentric Viewing nonhuman animals in terms of human motives, and experience and capabilities; emphasizing the importance of humans over everything else.

Language Nonhuman animals haven’t been considered capable of communicating about external events, objects, or other animals. It has been assumed that nonhuman animals use a closed system of communication, where vocalizations don’t include references to specific external phenomena.

Kanzi Kanzi, a Bonobo, began using symbols when he was 21/2 years old and his younger half-sister began using symbols at 11 months old. Both went to training sessions with their mother, but neither had been taught or were involved in the sessions.

Thinking About Humans How is primate communication similar to and different from full human language?

The Biological Continuum Human brains are larger than primate brains, but the neurological processes are functionally the same. The necessity of close bonding with at least one parent Need for physical contact Developmental stages and dependence on learning Capacity for cruelty, aggression, compassion, altruism, with humans more adept at cruelty and compassion and capability to reflect on behavior

Why It Matters Can we learn anything useful for our own species by observing primates in their natural settings? Evidence of self medication by chimpanzees suggests that we may be able to identify beneficial human drugs by observing chimpanzee behavior.

Why It Matters Primatologist Richard Wrangham noted that chimpanzees occasionally seek out a leaf that isn’t normally part of the diet. Analysis revealed the leaf has high levels of antibiotic properties, suggesting chimpanzees use it to control intestinal parasites. Plants consumed by chimpanzees contain compounds that may be useful for controlling malaria, Staphylococcus infections, E. coli, and cancer.