Patas Monkey (Erythrocebus patas)
The Patas monkey is one of the terrestrial primates restricted to the dry savanna of north-central Africa. The Patas could be confused with the Vervet monkey, but it has a lankier build, a light reddish-brown coat, and a black stripe above the eyes (the vervet is monkey grayer and has a black face mask).
Patas monkeys are a slender species colored red-brown dorsally and grey-white ventrally. The face can be recognized by a black brow ridge and nose as well as by the white area around the mouth. Adult E. p. pyrrhonotus have a white nose, changing from black as they approach sexual maturity. During pregnancy, the facial hair of female patas monkeys noticeably lightens, potentially as a result of changing hormone levels.
Males possess a bright blue scrotum. Patas exhibit a large degree of sexual dimorphism with adult males weighing 12.4 kg (27.3 lb) and adult females weighing 6.5 kg (14.3 lb) on average.
The patas male measures, excluding the tail, 600 to 875 mm (23.6 to 34.4 in) and the female measures 490 mm (19.3 in) on average. The maximum recorded longevity for a patas monkey in the wild is 21.6 years (Ross 1991).
Patas monkeys are physically adapted for life on the ground. Their slender bodies and long limbs are morphologically suited for terrestrial movement and speed rather than for arboreal movement. Patas monkeys are quadrupedal and their terrestrial locomotion is extremely quick for a primate monkey, with a maximum speed of approximately 55 km per hour (34.2 mph) reported (Hall 1965). Their especially long forelimbs facilitate this high running speed which provides an avenue of escape from predators.
In addition, they will occasionally assume a bipedal stance when alarmed, and can move bipedally if carrying an item in both hands. The tail curves down while on the ground, but is raised when on a narrow surface such as a tree branch, most likely for balance. When descending, the tail performs as a brace and controls the monkey’s descent.
In Uganda, the patas monkey is restricted to the extreme north, where it can be seen in Kidepo and Murchison Falls national parks, as well as the Pian Upe Wildlife Reserve.
It is also known as the hussar monkey. The race found ill Uganda is the Nile patas or nisras (E. p. pyrrhonotus).