The Patas Monkey (Erythrocebus patas) is a groun-dwelling monkey distributed over West Africa, and into East Africa. It is the only species classified in the genus Erythrocebus. Patas monkeys avoid dense woodlands and live in more open savanna and semi-deserts. The Patas Monkey grows to 85 cm in length, excluding the tail, which measures 75 cm. Reaching speeds of 50 km/h, it is the fastest runner among the primates.