Most have four types of teeth: incisors, canines, premolars and molars.

Most primates are quadrupedal, using all four limbs in their locomotion.

Arm swinging is found among the apes.

Prehensile tails, found only among the new world monkeys, are used as an aid to locomotion.

Below: 4 main locomotor patterns, although n.b. primates are flexible and able to move in more than one way (unlike some animals, e.g. dogs, horses are more restricted in their locomotion)

Skeletons are from:

*Arboreal (bearded saki) New World - prehensile tail

*Vertical clinger/leaper (indri)

*Brachiator (gibbon)

Modern African apes and humans last shared a common ancestor between 5 and 8 m.y.a.   We are closely related, and although the apes are not themselves frozen in time, they can shed light on early hominid behaviour, as well as modern human behaviour

Nonhuman primate behaviour has been systematically studied since the early 20th century (captive baboons, London Zoo), but that was intermittent, and the first wild population studies came later, 1960s. (e.g. ape studies: Fossey, Goodall, Galdikas)

 Many species, such as arboreal monkeys, have scarcely been studied at all.

n.b. many have been studied primarily in captivity, and this shapes their behaviour and our understanding of them (e.g. dominance hierarchies in baboons)

n.b. there are serious logistical challenges to some studies in the wild -- e.g. nocturnal, arboreal, very rare, etc. -- meaning that we don`t actually understand many primates very well yet!

n.b. there has also been a tendency to study primates for specific human agendas, rather than for themselves

Like many higher-order vertebrates, primates have both innate and learned behaviour. Behavioural plasticity (capacity to change) is a key primate adaptation.

To understand behaviour in a species, including social structure, you need to understand:

* diet (including quantity, quality, caloric value of foods)

* spatial distribution of foods (lots everywhere, scattered, clumped...)

* distribution and reliability of water sources

* body size, basal metabolic rate (energy requirements)

* distribution and types of predators

* distribution of sleeping sites

* activity patterns - nocturnal, diurnal, crepuscular

* relationships with other (nonpredator) species, including primate and nonprimate

* impact of human activities (if primates are being observed, they are being impacted!)

Many variations are correlated to body size. E.g. male and female primates that live in pairs tend to be nearly the same size (gibbons), whereas in species that live in groups, there is more sexual dimorphism (gorillas, baboons)

Dominance has historically been a major focus for primatologists, but reanalyses have shown that it can be a bit overrated. (Perhaps early British primatologists studying baboons in captivity saw a mirror of British society... Zuckerman vs. Strum)

Broadly speaking, factors that influence status:

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.

Many primate expressions are familiar to us, but n.b. their function has shifted a bit in humans. e.g. the fear grin and our smile can be similar.

N.b. Staring is very bad behaviour among primates.

Primates might defend a core area within their permanent home.

Jane Goodall witnessed unprovoked, brutal attacks of chimpanzees by other chimpanzees.... apparently territorial at least some of the time

Territoriality and acquisition of females are the motives suggested for chimpanzee male aggression.

Reinforce bonds between individuals and enhance group stability:

Male and female Bonobos may mate even when the female is not in estrus, a behavior that is not typical of chimpanzees or other primates. (Also more same-sex activity in this species... very frequent sexual activity)

Non-human primates have a range of mating patterns, ranging from permanent pairs (gibbons and callitrichids) to `favourite` partners, to more widespread mating.

Permanent bonding is not common among nonhuman primates.... but it does exist. So do `consortships`.

Primates produce only a few young in whom they invest a tremendous amount of parental care. (k –selected rather than r-selected)

The young are very dependent upon their mothers and the group.

http://primates.com/orangutans/baby.htm

And young primates (like many young mammals) play a lot

http://primates.com/snowmonkeys/snowball.html

The basic social unit among all primates is the female and her infants.

Monkeys raised without a mother were not able to form lasting affectional ties - Harlow.

The mother-infant relationship is often maintained throughout life.

The role of the male varies according to species: some (e.g. callitrichids) are very active parents, whereas others play no particular role.

Others in the social group may also engage in parenting behaviour, e.g. older siblings, other relatives.

Cultural behavior is learned and passed from one generation to the next.

Chimpanzee culture includes tools such as termite fishing sticks and leaf sponges.

http://primates.com/chimps/chimpwat.htm

Social interactions and problem-solving abilities demonstrate primate intelligence.

The fact that apes can’t speak has more to do with their anatomy and the language related structures of the brain than intelligence.

They do have communication systems, and our understanding of these is constantly developing.

http://www.pbs.org/teachersource/scienceline/archives/aug99/aug99.shtm

Human brains are larger than primate brains, but the neurological processes are functionally the same.

Nonhuman primates think and have feelings. We may not understand them, but that does not disprove their presence.

An astonishing blindness: That humans are part of an evolutionary continuum is the basis for animal research, yet we cage nonhuman primates with little regard for their needs.

Captive primates should be maintained in social groups and have access to habitat enrichment programs.