1. PARENTAL BEHAVIOR

2. The first social interactions of a newborn primate are with mother
The first social interactions of a newborn primate are with mother. The mountain gorilla is very careful to support her young infant as it clings to her. All primates seek contact with mother as soon as they are born -- and most are able to cling on their own within a day or two of birth.

3. Unlike many other animals, primates do not leave their infants in a nest or other protected area. Instead, mothers carry their infants wherever they go. Infants may cling to the belly or, as this young uakari is doing, ride on mother's back.
Scientific name: Cacajao calvus uakari -- wah-CAR-ee

4. Contact with the mother is an important first social experience for humans, too.

5. Although all primates live in social groups, the nature of those groups differs between species. Group size, the number of adult males and adult females, and who does most of the breeding all vary between species.

6. The siamangs shown here live in a family unit consisting of an adult male, adult female and their young offspring. This is similar to the basic living unit of many humans -- mom, dad and the kids.
Family group of siamangs showing adult male (top), adult female (middle) and their offspring (bottom).
Scientific name: Symphalangus syndactylus siamangs -- SI-a-mangs

7. Group of mountain gorillas in African forest.
Other primates live in groups with only one adult male and several adult females plus their offspring. In a gorilla group the adult male, called a silverback, fathers the offspring of all the females living with him.
Group of mountain gorillas in African forest.

8. Multi-male groups are also common among the primates
Multi-male groups are also common among the primates. Chimpanzee bands are made up of several adults of both sexes and their offspring. Such bands are temporary associations of animals who live in a larger community. Relationships between adult males are very important in these groups.
Three male chimpanzees sit together. Photo taken in a zoo group. Scientific name: Pan troglodytes

9. PLAY

10. All primates play. Here a group of lemurs engage in the most common form of play. This activity, characterized by chasing and wrestling, is called rough-and-tumble play. It seems to allow young animals to learn their own strengths and weaknesses, as well as that of their peers.
Group of ring-tailed lemurs wrestling. Scientific name: Lemur catta lemurs -- LEE-mers

11. For most primates, play involves physical contact
For most primates, play involves physical contact. Here are two chimpanzees wrestling.

12. Gorillas like to wrestle too

13. Social play occurs when two or more individuals engage in a behavior that has no apparent serious purpose, although it may resemble the behaviors used by adults in their social lives. Humans often call this playing games.

14. Knowing the intentions of other group members is vitally important to social animals. Primates use all the senses -- sight, smell, hearing, taste and touch -- in communicating with each other.

15. All primates rely heavily on vision to explore their world
All primates rely heavily on vision to explore their world. It is not surprising that facial expressions are an important communication tool. The youngest animals quickly learn to recognize the play face. The rhesus macaques, shown here with mouth open, demonstrate the play face seen in all monkeys, apes, and even humans at play.
Two rhesus monkeys wrestle.The animal on top (with head upside down) shows the open mouth play face. Scientific name: Macaca mulatta rhesus macaques - REE-sus ma-KACKS

16. Primates are also very good at communicating when they are not happy about a social interaction. Here another rhesus monkey screams and grins. This bared teeth expression is usually shown by the loser in a less-than-friendly encounter.
A mother rhesus macaque at center with her offspring responds to threats from two other monkeys.

17. Many primate species have unusual faces
Many primate species have unusual faces. This golden snub-nosed monkey from China shows an eye-catching combination of contrasting facial colors.
Closeup of face of a golden snub-nosed monkey. The flaps of skin at the corners of the mouth are a normal facial feature of adult males in this species.

18. The bow is a sign of submission that indicates to the animal receiving it that he or she is dominant. Most primate groups have a dominance hierarchy. Lower ranking animals can avoid fights with higher ranking animals by performing a formal sign of submission, such as a bow, when tensions are high.

19. Primate body language can be very impressive
Primate body language can be very impressive. Here an adult male chimpanzee, on the left, stands with all his hair on end. This is called piloerection -- it makes an animal look larger to the nearby audience.
Three chimpanzees in a zoo enclosure. The adult male on the left facing the camera is getting ready to run by the animals on the right.

20. These lemurs are using another kind of body language -- signaling with their tails in the air. Tail position can communicate alertness and self-confidence.
Three ring-tailed lemurs from a captive group stand with tails in 'question mark' position. Animals are wearing identification collars.

21. Body language is also important in humans
Body language is also important in humans. A hand-shake is a common expression of goodwill between people.

22. Primates use their sense of smell to communicate, too
Primates use their sense of smell to communicate, too. Here a sifaka leaves a scent mark on a tree.
A sifaka (related to the lemurs) rubs a scent-producing anal gland against the bark of a tree. Scientific name: Propithecus verreauxi sifaka -- sih-FAHK-ah

23. Most primates live in forests, and are able to produce some calls that carry long distances, such as hooting by this chimpanzee. Softer sounds are used when group members are near each other. Humans use sound to communicate when they talk.
Adult male chimpanzee stands bipedally and hoots.

24. Touch is a very important sense for primates
Touch is a very important sense for primates. Social animals have many friendly interactions throughout the day -- and most involve some form of touch. Mothers and infants spend a lot of time in contact, as do play partners, sexual partners, and other members of a social group.

25. An adult female stumptail macaque presents to an adult male
An adult female stumptail macaque presents to an adult male. He responds by touching her rear, and visually inspecting it for signs that she is in her fertile period and thus ready to mate.
An adult female stumptail macaque presents her genital area to an adult male. He will look, smell, touch and even taste her secretions to learn if she is ready to mate. Primates rely on many signals to determine the reproductive state of animals of the opposite sex.

26. The female Japanese macaque reaches back and looks at her partner during their mating.
Later in the same sequence, the female Japanese macaque looks over her shoulder at the male. This often occurs when the male ejaculates.

27. Physical contact between animals is a part of most friendly interactions in primates. Here two Japanese macaques sit together in close contact

28. Social grooming not only helps animals keep clean; it reinforces bonds between related animals and other members of a social group.
Three long-tailed macaques sit together. The adult female in the center grooms a juvenile on the right. Scientific name: Macaca fascicularis

29. In a group of monkeys, such as these long-tailed macaques, mothers groom their infants; females groom males; males groom females; older offspring groom their mother. All combinations of grooming partners are possible.
A large group of long-tailed macaques, including some mothers holding infants on their bellies, sit together. An adult male in the top row is being groomed by two other animals.

30. Social animals don't always get along with the members of their group
Social animals don't always get along with the members of their group. Fights and other forms of aggression are a common occurrence in primate groups.

31. Staring at an opponent is often part of a threat
Staring at an opponent is often part of a threat. This rhesus macaque shows the open mouth threat face used by many species of monkey.
A female rhesus macaque holding an infant stares off camera at an opponent.

32. Early observers of gorillas were impressed with their threats and displays. Here an adult male stands on two legs and beats his chest. This gained the gorilla the reputation as a very aggressive animal. Actually they are among the most peaceful of the primates.
Adult male silverback mountain gorilla stands bipedally while displaying in an African forest. Gorillas use a cupped hand position to make the sound associated with chest beating.

33. Fights between groups also occur
Fights between groups also occur. Here members of two troops of green monkeys face off. Again, threats and displays are the most likely form of aggression.
Members of two groups of African green monkeys threaten each other. Scientific name: Cercopithecus aethiops

34. All the members of a group may get involved in an intertroop fight
All the members of a group may get involved in an intertroop fight. These rhesus macaques threaten each other. In this species, females are often at the front when aggressive encounters with other groups occur
Two large troops of rhesus monkeys threaten each other. Notice that several females carrying infants are in the front ranks.

35. Sometimes intergroup fights involve males only.

36. Knowing all the members of its group is important to a social animal
Knowing all the members of its group is important to a social animal. New animals may migrate into a group from other areas -- but most new members of a group are born there.

37. Adult male lowland gorilla touches a young infant in a zoo enclosure.
Everyone is interested in new babies. This adult male gorilla gently touches an infant.
Adult male lowland gorilla touches a young infant in a zoo enclosure.

38. In most species, mothers do most of the child care
In most species, mothers do most of the child care. However in some species, fathers may carry infants most of the time. Here a tamarin male carries a youngster.
Adult male saddleback tamarin carries a youngster on his back. Scientific name: Saguinus fuscicollis

39. Grandparents may also have a special interest in the next generation
Grandparents may also have a special interest in the next generation. All primates must have the ability to adapt to changing social relationships. They begin learning social skills at birth and continue to practice them throughout life.