Vervet Monkey Biology, Behavior, and Adaptation

Introduction and Taxonomy

The vervet monkey, or Chlorocebus, belongs to the Old World monkey classification of medium-sized primates. Science typically recognizes six species, though there is ongoing disagreement as to whether these represent distinct species or a single species with subspecies. For the entire genus Chlorocebus, the terms "vervet" and "green monkey" are used interchangeably, even though these names also serve as common names for some individual species within the group (Groves).

The full taxonomic classification of Chlorocebus is as follows:

Suborder: Haplorrhini
Infraorder: Simiiformes
Superfamily: Cercopithecoidea
Family: Cercopithecidae
Subfamily: Cercopithecinae
Genus: Chlorocebus

Species: Ch. aethiops, Ch. cynosuros, Ch. djamdjamensis, Ch. pygerythrus, Ch. sabaeus, Ch. tantalus

Subspecies: Ch. p. excubitor, Ch. p. hilgerti, Ch. p. nesiotes, Ch. p. pygerythrus, Ch. p. rufoviridis, Ch. t. budgetti, Ch. t. marrensis, Ch. t. tantalus

Other names: Ch. aethiops: Cercopithecus aethiops or Chlorocebus aethiops; grivet or savanna monkey; singe vert (French); grünmeerkatze (German); mono verde (Spanish); grön markatta or vervett (Swedish). Ch. cynosuros: malbrouck. Ch. djamdjamensis: Bale Mountains vervet or djam-djam. Ch. pygerythrus: vervet monkey. Ch. sabaeus: green monkey. Ch. tantalus: tantalus monkey (Vervet Chlorocebus).

Morphology

Typically, the vervet monkey has a yellow to green-brown coat with white undersides and white fur on the brows and cheeks. The skin on the abdomen is bluish, while the face, hands, and feet are black-skinned. Males of all species have a bright blue scrotum and a bright red penis. There is often some variation in fur length and coloration among individuals and populations.

Males and females are sexually dimorphic. Adult males weigh between 4 and 8 kg and measure between 400 and 600 mm; adult females weigh between 3 and 5.5 kg and measure between 300 and 500 mm. Vervets move as quadrupeds and are comfortable both on the ground and in trees, making them semi-terrestrial and semi-arboreal. Lifespan is difficult to determine due to high rates of predation in the wild, but captive individuals show serious health problems after 11 years, leading scholars to estimate a maximum lifespan of approximately 12 years in captivity and roughly 7 years in the wild (Wolfe-Coote).

Geographic Distribution and Diet

The vervet is found in East Africa and can inhabit mountainous areas up to approximately 13,000 feet in elevation. They do not live in deserts or true rainforests, but prefer woodlands along streams, rivers, and lakes. They are diurnal, sleeping and feeding in trees. Vervets are, in fact, the most widespread of the African monkeys, inhabiting large parts of the sub-Saharan regions of the continent. They are typically found from Senegal to Ethiopia, north into Egypt, and south into South Africa, though they are absent from the forests of the Congo Basin. Some recent conflicts in Africa have made precise study of the vervet's range difficult, but they have been recorded in 39 African nations as well as in the Cape Verde Islands. Sea travel introduced the vervet to the Caribbean, where they are at times considered a pest species (National Research Council).

Because they are so widespread, seasonal availability of food and water means that vervets must forage extensively and consume a wide variety of material. Along with chimpanzees and baboons, they are among the most omnivorous of the primates. Their diet includes leaves, seeds, nuts, grasses, fruit, berries, flowers, invertebrates, eggs, birds, lizards, and rodents, though they show a clear preference for flowers and fruit. One ecological consequence is that vervets frequently raid farms for sweet potatoes and corn, creating conflict with agricultural communities.

Works Cited

Cheney, D., and R. Seyfarth. How Monkeys See the World. University of Chicago Press, 1990.

Groves, C. "Genus Chlorocebus." Mammal Species of the World, edited by D. Wilson and D. Reeder, 3rd ed., Johns Hopkins University Press, 2005, pp. 158–60.

National Research Council. International Perspectives on the Future of Nonhuman Primate Resources. National Research Council, 2002.

"Vervet Chlorocebus." Primate Info Net, 21 November 2011, pin.primate.wisc.edu/factsheets/entry/vervet. Accessed February 2012.

Wolfe-Coote, S., editor. The Laboratory Primate. Elsevier, 2005.