“whoop… whoop… whoop!” The branches shake and dark objects scatter across the treetops. If you are standing in the tropical forest you probably just heard monkeys over your head. Agile and acrobatic monkeys easily leap through the forest but are often difficult to see and study.
Most monkeys live in tropical regions in the Americas, Africa, and Asia and spend much of their lives in treetops. Monkeys belong to a larger group of mammals called primates. Primates have large brains, grasping hands and include lemurs, apes and humans. Like other primates, monkeys are very intelligent and curious and like you, have forward-facing eyes for great depth perception.
There are more species of monkeys than apes. Monkeys and apes are both primates, just like humans. Can you tell which one is a monkey?©G. Ellis/GLOBIO.org
Old World and New World Monkeys
Monkeys are divided into two main groups: Old World monkeys and New World monkeys. These groups have been evolving independently from one another for millions of years.
Baby pigtail macaques may be taken by other adult females in the group. All females in the group show great interest in infants, and higher-ranking females often grab lower-ranking females’ infants.©G. Ellis/GLOBIO.org
Old World monkeys
Old World monkeys, such as mandrills and baboons, are native to Africa and Asia. Old World monkeys live in a variety of different habitats, from grasslands to rainforests to snowy mountain peaks. They can live in the trees or on the ground. In general, Old World monkeys have:
- curved nostrils that are close together
- cheek pouches for storing food
- sitting pads on their rears
- tails that cannot grasp limbs and trees
Black handed spider monkeys eat a lot of food over a short period of time and they like to eat while hanging, climbing or moving. Using their prehensile tails to swing through the forest, spider monkeys can move very fast.©G. Ellis/GLOBIO.org
New World monkeys
New World monkeys live in South and Central America and Mexico mostly in the trees in tropical rainforests. In general, New World monkeys have:
- nostrils that are far apart
- no cheek pouches
- no sitting pads on their rears
- prehensile tails, which can grasp limbs and trees.
Largest and Smallest Monkeys
The face and rear of the male mandrill can become brighter in color when excited. It becomes more colorful as they get older. Their blue, red and purple face and rear can help to identify one another when searching for food.©Vincent van Dam
Baboons and mandrills weigh in as some of the largest in the monkey world. Both of these Old World monkeys live in Africa. The males weigh up to 30-36 kg. Their primary predators are human beings, who hunt them for food. Mandrills are endangered because of this hunting.
The smallest monkey species is the pygmy marmoset, which is a New World monkey. Adults weigh 113 to 119 g. Pygmy marmosets are found in the tropical rainforest in the upper Amazon basin in South America. They live mostly in trees and are active during the day. They are not currently endangered. However, scientists are concerned about their population because pygmy marmosets are increasingly being sold as pets.
During the first month of life, baby olive baboons nurse and sleep frequently with their mother. As they get older, olive baboons play by themselves or with their peers and they will become more active.©G. Ellis/GLOBIO.org
Pregnancy and birth in monkeys varies by species. The pygmy marmoset lives in a group of six. Only the dominant female in the group has babies. Offspring are often fraternal twins--the kind of twins that don’t look exactly alike. After birth, the offspring are carried around by the males in the community. They are returned to the mother for nursing.
Squirrel monkeys are also New World monkeys, but they have different birth habits. After birth, the newborn clings to its mother’s back rather than being carried by males. Other female squirrel monkeys, rather than males, share newborn care with the mother.
The lifespan of monkeys depends on the species. In the wild, squirrel monkeys can live up to 20 years. Squirrel monkeys spend their lives in trees and are vulnerable as prey for eagles. Howler monkeys live 15 to 20 years in the wild. Howler monkeys have been hunted and their habitats have been destroyed. This greatly decreases the lifespan of the species. Mandrills live up to 45 years in the wild. They are also hunted for food.
Monkeys have bodies that are similar in a lot of ways to our own, with arms, legs, and thumbs that can move easily. They also have flexible arms and legs for grasping and climbing. But you might be surprised that they can not swing through the branches. Only apes and humans can swing from trees, monkey’s shoulders are not designed to allow for swinging.
Old World and New World monkeys look considerably different, as you can see below. Baboons are Old World monkeys and capuchins are New World monkeys.
Click on the picture to learn more.
Groups Called Troops
An olive baboon troop, or group, forages for food. Troops of olive baboons are mostly made up of females and their young, but include a few males.©G. Ellis/GLOBIO.org
Many species of monkeys live in groups called troops. Troops allow monkeys to protect themselves from predators, such as humans. In Africa, mandrills can live in troops of up to 45 monkeys. Mandrill troops are led by a dominant male, which has the brightest colors on his face--and also on his rear! The troop also includes several breeding females and their offspring. Western red colobus monkeys live in troops of up to 80 monkeys. The large size of their troops helps protect them from the humans and chimpanzees that hunt them for food.
Vocal and visual communication is important to olive baboons. In the most stressful situations “screams” can be sounded, as a high-pitched and continuous vocalization. These can be a response to intense emotions of pain, fear, or aggression.©G. Ellis/GLOBIO.org
Monkeys communicate with hand gestures, facial expressions, and noises called vocalizations. Vocalizations can be quite complex and are often used to warn other monkeys of predators. Mother monkeys can distinguish the vocalizations of their own infants from other babies. There is also evidence that suggests that some monkey species have developed rules for putting together phrases.
Staring is thought to be a threat in monkey communities. Staring is often followed by looking away if confrontation is to be avoided. Showing of teeth is often also interpreted as a threat.
Here Comes the Groom
Monkeys form relationships with other monkeys in their species in different ways. They bond with one another by grooming. They check each other for parasites and clean themselves. They also bond by eating and sleeping close to one another.
What’s for Dinner? Everything!
The pygmy marmoset uses its teeth to poke holes in certain trees and vines. Sixty-seven percent of their feeding time is spent eating tree gum or preparing new food sources by gnawing tree trunks or large branches.©David Lewis
Monkeys are omnivores. This means they eat a variety of different foods. Many species of monkeys eat fruits, seeds, roots, herbs, and insects. Some monkeys eat very particular types of foods. Pygmy marmosets drill holes in trees and drink the tree sap, called gum. They’ll also eat insects, lizards, spiders, and fruit. Diets of monkeys are so full of variety that in a year a monkey may eat 200 different things!
The greatest threat to monkeys is the loss of habitat. Often the building of roads and the logging of forests destroys the areas monkeys use as homes. Without places to live, monkeys are more vulnerable to predators, including human beings who hunt monkeys for food. By focusing on environmental education and preserving habitats as well as making laws to protect monkeys, species including the mandrills, brown spider monkey, and red colobus monkey, may be spared extinction.