are the smallest Old World Monkey. Head and body length is 320-450
mm and tail length is 360-525 mm. Weights of males are about
1250 grams and females about 760 grams. The pelage is a greenish
grey or black to greenish yellow or buff. Underparts are white
or greyish white. The face is bare except for a few black hairs
on the upper lip which is sometimes yellow. The cheeks have
yellow fur tipped with black and there is a black line which
extends from the eye half the distance to the ear. The eyes
are black as well and are surrounded by yellow or orangish skin.
The fur at the top of the head is black suffused with ochre
and a mane of white extends across the neck and chest from the
base of one ear to the other. The outer limbs are a pale yellow
tinged with red and the hands and feet are similarly colored.
The tail is grayish brown or black above and yellowish bellow
with a blackish tip. Variations among individuals are from an
overall olive to a true green tint.
They appear to prefer rainforests along rivers. The main diet
consists of fruits and insects.
are apparently non-territorial, with adult males acting as leaders
during the day and sentinels at night. Adult females outnumber
adult males and for a distinct subgroup with their infants and
juveniles up to one year of age. Gestation is from 158-166 days
and the infants are about 230 grams at birth. Sexual maturity
is reached at age 4.5 in females and about 1-2 years later in
found in Liberia; Cote d'Ivoire; Nigeria apparently to the Itimbiri
River in NW Dem. Rep. Congo, Central African Republic; Rio Muni
and Bioko (Equatorial Guinea).