Procolobus verus
olive colobus

Procolobus verus is found on the western coast of Africa, from Sierra Leone to Tongo. There is also an isolated population in eastern Nigeria.

(Burton and Pearson, 1988; Oates and Whitesides, 1990; Flannery, 2000; Nowak, 1997) (Burton and Pearson, 1988; Flannery, 2000; Nowak, 1997; Oates and Whitesides, 1990)

Olive colobus monkeys are arboreal and are restricted to rainforest habitat. They prefer the dense understory of the forest, often near water. Procolobus verus sometimes travels into the middle canopy to sleep, but never ventures to the upper stratum.

(Burton and Pearson, 1988; Flannery, 2000; Nowak, 1997) (Burton and Pearson, 1988; Flannery, 2000; Nowak, 1997)

Procolobus verus is the smallest and the most drab colored of all African colobus monkeys, bearing olive colored hair with a tinge of brown on top and grayish underparts. Weights range from 2 to 4.5 kg, and body lengths of 90 to 430 mm are reported. Procolobus verus has a similar body structure to black and white colobus monkeys, but olive colobus monkeys have a small crest on top of the head and the most reduced thumb and largest feet of any colobine. Males are equal in size to females with relatively larger canines than females.

Procolobus verus possesses six cusps on the lower third molars.

(Burton and Pearson, 1988; Nowak, 1997) (Burton and Pearson, 1988; Nowak, 1997)

These colobines are reported to be polygynous.

Olive colobus monkeys have a gestation period of 5 to 6 months, with no specific breeding season. Females reproduce about every two years and usually bear only one young at a time. Females reach sexual maturity around 3 to 4 years old, males around 5 to 6 years old. Female P. verus have perineal organs that swell during estrus. (Flannery, 2000)

Female P. verus carry their young around in their mouths for a few weeks after birth, a behavior not observed in Colobus species. As the young matures, it is carried on the abdomen of the mother. Mothers provide milk, grooming and protection for the young. The role of males in care of infants has not been reported.

The lifespan of these animals has not been reported, but other leaf eating monkeys rarely live in excess of 30 years in captivity. It is likely that P. verus is similar. (Nowak, 1997; Nowak, 1997)

Procolobus verus is diurnal and uses quadrapedal locomotion. Troops of P. verus consist of an old male, several females and their offspring. Group size ranges from 10 to 15 individuals. This species is often seen grouping with other monkeys, especially Diana monkeys. When an alarm call is sounded, usually by a Diana monkey, P. verus sits very still, camouflaged by the green color of its pelage.

(Burton and Pearson, 1988; Oates and Whitesides, 1990; Flannery, 2000; Noe and Bshary) (Burton and Pearson, 1988; Flannery, 2000; Oates and Whitesides, 1990)

Communication in these monkeys is not well described. However, we may assume that they are like other primates, and use various means of communication. Included in these are visual signals, such as facial expressions and body postures, vocalizations, and tactile communication, including grooming, playing, and aggression. (Nowak, 1997)

Procolobus verus forage in understory and middle canopy of the forest, feeding mainly on young leaves. These monkeys are highly selective feeder, but seasonally they will also eat seeds, flowers, and petioles. When young foliage is available, they ignore mature leaves. Procolobus verus has a sacculated stomach to assist in the breakdown of cellulose in its primarily folivorous diet.

(Flannery, 2000; Oates, 1988) (Flannery, 2000; Oates, 1988)

Procolobus verus is the most accomplished leaper in the Tai Forest, where it commonly lives. This capability of P. verus allows it to avoid predators that share this habitat. It also frequently groups with Diana monkeys to avoid predation. Procolobus verus is hunted by humans for its meat and skin.

(Noe and Bshary)

The ecosystem role of these animals is not well understood. We may assume that to the extent that other animals prey upon these monkeys, they serve as a control on predator populations. They may also help to disperse seeds.

Procoloby verus is hunted by humans for food.

There are no known adverse effects of P. verus on humans. However, as primates, they may carry some of the same disease organisms which affect people.

Although this species is not of special conservation concern, all primates are listed as CITES appendix II because they are vulnerable to habitat loss.