Patas Monkey - The patas monkey, also known as the Wadi monkey or Hussar monkey, is a ground-dwelling monkey distributed over semi-arid areas of West Africa, and into East Africa. The patas monkey grows to 33 in. in length, excluding the tail, which measures 30 in. Adult males are considerably larger than adult females. Reaching speeds of 34 mph, it is the fastest runner among the primates.