Vervet Monkeys - The Least Concern Primates

Taxonomy
Vervets are Old World monkeys of the family Cercopithecidae (Butynski, 2002). Their classification has been updated recently and now they are considered to be their own genus, having been moved from Cercopithecus to Chlorocebus (Groves, 2001; Grubb et al., 2003). Their taxonomy is far from clear and they are often grouped with guenons (medium sized, arboreal African primates of the genus Cercopithecus) (Lernould, 1988). Currently there are six species officially recognised - Chlorocebus aethiops, Chlorocebus pygerythrus, Chlorocebus tantalus, Chlorocebus sabaeus, Chlorocebus cynosuros, and Chlorocebus djamdjamensis. There will doubtless be further revision in the future and an increase in the number of species or subspecies (Grubb et al., 2003).
Some species are clearly separated geographically. But there are hybrid zones.

Morphology
Pelage colour and fur length vary from species to species, as does the presence or absence of a distinguished band of fur on the brow. Ch. aethiops, Ch. pygerythrus, Ch. tantalus and Ch. cynosuros have a yellow to greenish-brown coats., black skinned hands and white brows. Ch. sabaeus has golden-green fur, does not have the white band on the brow and lacks the black skinned hands and feet. Ch. djamdjamensis has longer darker brown fur, with a white beard and a very slight white brow. All six species have white undersides (Rowe, 1996; Grooves 2001). Babies are born with black natal coats which gradually change to adult colouration in 3 to 4 months (Lee, 1984).
All males display sexual dimorphism weighing up to 8kg where females weigh up to 5.3kg. Males of the species have bright blue scrotal areas and contrasting bright red penises (Fedigan & Fedigan, 1988). Ch. sabaeus has a paler blue scrotal area.
They move quadrupedally and are semi-arboreal, semi-terrestrial (Fedigan & Fedigan, 1988). They have cheek-pouches characteristics of the Cercopithecidae that allow them to forage and store food for later consumption.

Range and Habitat
Vervets are one of the most widespread of the African primates and various species are found in different areas in most of sub-Saharan Africa (Wolfheim 1983; Lernould 1988). Range maps of the six currently recognised species are displayed on the following pages.
Vervets are generalists and can live in a wide range of habitat types (Wrangham & Waterman, 1981; Whitten 2005). They can inhabit humid rainforests, semi-desert environments, swamps. Their only limitation seems to be the presence of water and sleeping trees (Wolfheim 1983; Chapman & Fedigan 1984; Fedigan & Fedigan 1988). They are rarely found in the centre of forests and prefer the edges. They can be found in swamp areas also. They have a preference for wooded areas over dense forest. They survive quite well in secondary forests, cultivated land and can do relatively well in urban areas (Wolfheim 1983; Shimada & Shotake 1997).

Ecology
Vervets are among the most omnivorous of all the primate species, along with chimpanzees (Pan troglodytes, P. paniscus) and baboons (Papio species). They have been known to eat gum, leaves, shoots, flowers, shoots, seeds, berries, buds, fruits, nuts, fungi, eggs, insects, many other invertebrates, birds, lizards and small vertebrates. They have a particular preference for Acacia tortilas and A. xanthophloia (Wrangham & Waterman, 1981). In cultivated areas they eat grown vegetables, fruits, and cereals (Saj et al., 2001)
They vary both their diet and daily activity patterns according to environmental conditions (Harrison, 1983). Range size also varies according to group size and food and other resource abundance (Harrison, 1983).
In their natural habitat predators include snakes, various raptor species, lions, leopards, cheetahs, caracal and other felid predators. Their most serious predators are humans.
Vervets occur in multi-male multi-female groups with an alpha male. Females remain in their natant group and males migrate when they approach sexual maturity, usually at four or five years of age, in the company of other males their age (Cheney & Seyfarth, 1983). Females reach sexual maturity at four or five years of age while males reach sexual maturity between seven and ten years of age. Gestation period is 5.5 months and females usually give birth to a single offspring (Horrocks, 1986).