What is a Monkey?

A monkey is a member of the family Cercopithecidae that includes all the tailed primates. Its presence of a tail, along with narrow-chested bodies and other features, separates them from the great apes.

Most monkeys live in social groups, including related females and their young. They communicate using facial expressions, body movements, and various noises. For example, squirrel monkeys make more than 25 calls that sound like barks, purrs, screams, peeps and squawks. Howler monkeys emit deep, throaty howls that can travel 2 to 3 miles (5 to 5 kilometers).

Monkeys are good at solving problems. Some, such as baboons and mandrills, learn to use sticks to crack nuts. Others, such as capuchins and Japanese macaques, spontaneously use tools to obtain foods they cannot reach themselves. But they do not have the advanced problem-solving abilities of great apes such as gorillas and chimpanzees, which can improvise in new situations.

Many species have adapted to harsh environments such as desert-like savannas and snowy mountains. For instance, the Japanese macaques (Macaca fuscata) living in the northernmost regions of Japan have developed thick fur to stay warm.

While some monkeys live alone or in pairs, most are tree-dwelling herbivores that eat fruit, leaves, flowers, seeds, shoots and roots. Most also consume insects, birds’ eggs and small animals. A few monkeys, such as the colobus monkeys, have sacculated stomachs, which allow them to digest plants by fermenting their cellulose content with bacteria. This process produces energy rich gases that the monkeys breathe through their nostrils.