Monkeys: Facts about the largest group of primates

 A family of proboscis monkeys in a tree in Borneo. (Image credit: USO via Getty Images)

Monkeys are a large and diverse mammal group that includes most primates. Humans, chimpanzees (Pan troglodytes) and other apes share an ancestor with monkeys but belong to a separate group of primates that diverged from monkeys millions of years ago. Monkeys are typically smaller than apes and usually have tails, which apes lack. The monkey group doesn't include lemurs, which are another branch of the primate family tree and live in Madagascar.

There are a variety of monkeys, spread across the world, with very different lifestyles. They come in many shapes, sizes and colors, but they are all intelligent and social creatures.

Monkeys are broadly split into two groups: Old World monkeys and New World monkeys. Old World monkeys live in Asia and Africa and have downward-pointing nostrils, according to Nature Education. New World monkeys live in North and Sout

h America and have outward-pointing nostrils.