Which primate is the fastest runner, reaching about 55 km/h?

The patas monkey is the fastest-running primate, reaching about 55 km/h.

The patas monkey, commonly called the common patas monkey and scientifically Erythrocebus patas, is built for speed. It has long legs, a relatively slim body and a body plan suited to crossing open ground quickly. Unlike many primates that spend much of their time climbing, patas monkeys commonly travel through dry woodland and savanna habitats.

Their speed is closely tied to survival. When threatened, a patas monkey may flee across open terrain, where rapid acceleration and long strides can help it escape predators. Their reddish-brown coat and pale underside also set them apart from vervet monkeys and baboons, which are sometimes confused with them.

Patas monkeys live across broad parts of central, western and eastern Africa. They are social animals, usually seen in groups, and feed on fruits, seeds, leaves, insects and other food available in seasonal environments. The 55 km/h figure is an approximate maximum, not a routine cruising speed, but it is the standard record associated with the species.