What is a Monkey?

A monkey is a nonhuman primate that is very similar to humans in size and structure. They usually move through their habitats by clinging and swinging from tree branches, but some species also walk on all fours (quadrupedalism) or use their tails for balance. The term “monkey” is often used interchangeably with “ape”, but scientists distinguish the two groups by examining physical and behavioral characteristics. For example, apes have large brains and are very good at learning from experience, while most monkeys do not have this capability.

Monkeys usually live in the forests of Central and South America, Africa, Asia and Australia. Exceptions include Old World species like the rhesus monkey in North America and the Japanese macaque in Asia, which are terrestrial, or spend much of their time on the ground rather than in trees.

Most monkeys live in social groups called troops, which can range from a few to many individuals. Males and females mate within their troops. The members of a troop care for each other and help raise offspring. Some species of monkeys exhibit sexual dimorphism, or differences between sexes in appearance. This can include coloration, the length of a crest or horns, or a different shape of the mouth and teeth.

Some monkeys eat fruit, leaves, seeds and roots; others specialize in one food item. For example, proboscis monkeys eat fruit when it is ripe and then switch to eating only leaves during the dry season. Other species, such as the nocturnal owl-faced monkey (Cercopithecus nigricans), rely on a diet of insects, including worms and caterpillars.