Cercopithecus aethiops
Afrikaans: blouaap
Zulu: inkawu
German: Grünmeerkatze
French: Vervet
The vervet monkey is roughly 45-50 cm high when sitting erect and has a mass of 4 – 5 kg. Its tail is roughly 65 cm long. It has a grey coat with yellow tinge with a black face, hands, toes and tail tip. There is a band of white across the forehead and this goes down the sides of the face to the chin. The under parts are whitish or white. The tail is approximately the same colour as the upper parts and tends to darken towards the tip.
The structure of the hair shafts are so designed to allow the vervet monkey to swim and dive in the water, the main coarse hair forms an isolation when wet with hot air trapped in between the hair shafts, thus acting as a wet suit. The long tail is to maintain the balance of the body when moving through the trees. The fore and hind limbs are sub-equal in length with the hind legs longer than the front. Each leg is equipped with a foot that also acts as a hand, with five fingers/toes on the fore and hind feet. Each finger / toe has a flat nail, similar to those of the human counterpart. The hands / feet are narrow and elongated, the thumb and index finger fully opposable, the palms / soles are naked. The front limb fingers are used to take and hold food as well as for digging out bulbs and tubers.
Vervet monkey walks on all four legs. The body is held horizontally and when walking the limbs alternate in progression. They can also walk in an upright position using only the hind limbs like the legs of its human counterpart.
Vervet monkeys associate in troops of up to 30 individuals. Unlike baboons, which spend the greater part of the day on the ground, vervet monkeys are mainly arboreal, coming occasionally to the ground on their search for food. They are diurnal and gregarious, living together in troops of 15 - 20 animals, which are dominated by a mature male. Like baboons, they have a highly developed social structure, although their hierarchy is slightly more flexible than that of baboons. Authority is maintained with aggressive threats. Within the troops there is a clear order of dominance with an Alpha male as leader. Rank-order within the troop is maintained by threat and skill. Eyelid display as a threat gesture is common among vervet monkeys.
The skin of the eyelids and the area immediately above them are light-coloured, contrasting with the dark face. By retracting the brow these areas are exposed and when accompanied by a stare, this functions as a threat. In vervets the function of this gesture seems highly dependent on the posture assumed by the displayer. When crouching it functions as a defensive threat, whereas in the upright position it functions as a warning threat. Head bobbing or jerking is another warning gesture and inquisitive vervets demonstrate variations of this pattern representing a continuum from staring to attack. When a subordinate member of the troop is threatened or bitten, it redirects its own anger to the member next down on the scale from it in the course of status maintenance. Subordinates are bitten most often on the tail. The tail bite wound is never fatal.
The desire to groom and be groomed has a dual function, as it rids the monkeys of parasites, and is also an important factor in troop cohesion. Grooming takes place at all times. High rates of grooming were significantly correlated with high rates of alliance formation. High ranking members received more grooming than other members. Grooming is practiced by all members.
The males defend the troop while the females tend to their young. Vervets sleep together in groups of two or three in rock crevices or on the branches of trees. They are agile climbers and forage constantly in trees in search of food. Their chattering changes to loud coughing and agitated screaming when alarmed
Gender differences:
The sexes are similar, the female being slightly smaller than the male. The scrotum of the adult males has been described variously as bright blue, cobalt blue and turquoise green and is very conspicuous.
Habitat:
The vervet monkey has a wide distribution in Africa, from southern Ethiopia and Somalia to the Cape Province. In the Southern African Sub region, they occur in northern, north-eastern and southern Namibia; in northern, eastern and in parts of south-eastern Botswana; Transvaal; Swaziland; Mozambique; south of the Zambezi River; Natal; the western Orange Free State; in the eastern, southern and along the Orange and Vaal rivers in the Cape Province, where they occur coastally about as far west as the George and Knysna districts.
Vervet monkeys can live in a drier habitat than other members of this genus and are most abundant in and near riverine and savanna woodland, being generally absent from open grassland and open scrub. They will penetrate deep into otherwise totally unsuitable terrain along rivers and streams and will settle there if the riverine woodland is sufficiently developed to provide fruit bearing trees and cover.
Diet:
They are mostly herbivorous and eat fruit, flowers, seeds and leaves, although they will also eat spiders, grubs, lizards, birds and their eggs and locusts.
Reproduction:
Males and females become sexually mature at 30 months of age. The oestrous cycle is usually about 1 month. In the wild, births are more or less seasonal (depends on place), but in captivity births can occur in any month. The interval between births is approximately 1 year. There is no fixed mating season, and usually a single young is born (rarely twins) after a gestation period of seven months. The females are extremely maternal, and have been known to adopt young from other troops; a bereaved mother will often keep the body of her infant with her for several days. Babies have a yellow band which is formed by the deep yellow colouration of the tip of the hair above the eyebrow, with the face a sallow flesh colour. After a period of 6 months the infant is largely weaned. They can live for about 12 years in the wild.
Other:
Their predators include leopard, large eagles and pythons.
They are very good swimmers and, if necessary they can even dive.
The name originated from the French vernacular name of this species, cercopithèque vervet .
At the Vervet Monkey Rehabilitation Centre situated in Tzaneen, Arthur Hunt has identified after five years of intensive research more than forty words / sounds that the vervet monkey can produce.
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