Mantled guereza
The mantled guereza, also known simply as the guereza, the eastern black-and-white colobus, or the Abyssinian black-and-white colobus, is a black-and-white colobus, a type of Old World monkey. It is native to much of west central and east Africa, including Cameroon, Equatorial Guinea, Nigeria, Ethiopia, Kenya, Tanzania, Uganda and Chad. The species consists of several subspecies that differ in appearance. It has a distinctive appearance, which is alluded to in its name; the long white fringes of hair that run along each side of its black trunk are known as a mantle. Its face is framed with white hair and it has a large white tail tuft.
The mantled guereza is diurnal and arboreal, found in both deciduous and evergreen forests. It is an adaptable species that can cope with habitat disturbance and prefers secondary forest close to rivers or lakes. Although previously thought to eat only leaves, it also eats seeds, fruits, and arthropods. It is able to digest plant material with a high fibre content with its specialised stomach and may only eat from a few plant species at a time. It is preyed on by birds of prey and some mammals, such as the common chimpanzee and the leopard.
The mantled guereza lives in social groups of three to fifteen individuals. These groups normally include a dominant male, several females, and the offspring of the females. It has a polygynous mating system and copulation is initiated with vocal communication. After a gestation period of just over five months, infants are born with pink skin and white fur, which darkens to the adult coloration by three to four months. The mantled guereza is well known for its dawn chorus, the males' "roar" is a method of long-distance communication that reinforces territorial boundaries. It also makes other vocalization and uses body postures, movements, and facial expressions to communicate.
The mantled guereza is listed as Least Concern by the International Union for Conservation of Nature because it is widespread – although it is locally threatened in some areas, the decline is not great enough to list it in a higher category of threat. However, one subspecies found in Kenya is listed as Endangered. It can survive well in degraded forests and in some areas it is more common in logged areas than unlogged ones. The mantled guereza is also threatened by hunting for bushmeat and for its skin.
Etymology
The mantled guereza has many alternative common names including the guereza, the eastern black-and-white colobus, the magistrate colobus, or the Abyssinian black-and-white colobus. The name "mantled" refers to its mantle, the long silky white fringes of hair that run along its body and "guereza" is the native name of the monkey in Ethiopia. The scientific name Colobus derives from Greek kolobus meaning "mutilated" which refers to its lack of thumbs.Taxonomic classification
The mantled guereza was first classified by Eduard Rüppell, a German naturalist and explorer, during his trip to Abyssinia between 1830 and 1834. He wrote about the species in Neue Wirbelthiere con Abyssinien, Saengthiere in 1835. It was first seen in Europe in 1890 in Berlin Zoological Garden when three individuals were purchased from a dealer from Massawa, Eritrea.The mantled guereza is in the Colobinae subfamily, also known as the leaf-eating monkeys, a group of Old World monkeys from Asia and Africa. This subfamily is split into three groups, the colobus monkeys of Africa, of which the mantled guereza is a part, the langurs, or leaf monkeys, of Asia, and an "odd-nosed" group. The African colobus monkeys are divided again by distinctions in color, behavior, and ecology. The three genera are the black-and-white colobi, the red colobi, and the olive colobi. There are three black-and-white colobi: the mantled guereza, Colobus guereza, the king colobus, C. polykomos, and the Angola colobus, C. angolensis. Groves lists seven subspecies of mantled guereza in Mammal Species of the World . The validity of the Djaffa Mountain guereza, C. g. gallarum, is uncertain, although not listed by Groves in MSW, it is recognised in his 2007 Colobinae review paper, and by International Union for Conservation of Nature assessors Gippolliti and Butynski in 2008.
- Western guereza, Colobus guereza occidentalis, occurs from eastern Nigeria, Cameroon, and Gabon at the edge of its western range to South Sudan and Uganda, west of the Nile.
- Omo River guereza or Abyssinian black-and-white colobus, C. g. guereza, found in Ethiopia, in the highlands west of the Rift Valley down to the reaches of the Awash River, the Omo River, and in the Blue Nile gorge.
- Djaffa Mountains guereza or Neumann's black-and-white colobus, C. g. gallarum, found in the Ethiopian Highlands east of the Rift Valley.
- Dodinga Hills guereza, C. g. dodingae, found in the Didinga Hills in South Sudan.
- Mau Forest guereza, C. g. matschiei, occurs from western Kenya and Uganda south into northern Tanzania.
- Mt Uaraguess guereza or Percival's black-and-white colobus, C. g. percivali, found in the Matthews Range in Kenya.
- Eastern black-and-white colobus, C. g. kikuyuensis, occurs in Kenya on the Ngong Escarpment of Mount Kenya and in the Aberdare Range.
- Kilimanjaro guereza, C. g. caudatus, found in Tanzania and Kenya in the forests surrounding Mount Kilimanjaro and Mount Meru.
Physical description
The mantled guereza has a distinctive pelage, which is mostly black, with long white fringes of silky hair—known as a mantle or ornamentation—along the sides of its body and tail. The bands that make up the mantle start at the shoulders and extend along the back until they connect at the lower torso. The tail is long and ends in a white tuft which varies in how much it covers the tail. These features vary in color among subspecies, for example the tail of C. g. guereza is gray until the white tail tuft which covers half of its length, while the tail tuft of C. g. caudatus makes up 80% of the tail. The mantle color ranges from white to cream or yellow. Its face is framed by white hair and it has bushy cheek hairs. The thigh has a white stripe.Infants are born with pink skin and white hair. The hair and skin darken as they age and by three to four months they attain adult coloration. Male usually gain their coloration before females. The male typically weighs and the female weighs between. The head and body length averages for males and for females. Like most colobi, the mantled guereza has a small thumb that is vestigial. There is dentition sexual dimorphism among the subspecies. In some, the males have larger teeth than females, in others the reverse is true, and some have no significant difference.
Distribution and habitat
The mantled guereza is distributed throughout Equatorial Africa. It ranges from Nigeria and Cameroon in the west to Ethiopia, Kenya, Uganda, and northern Tanzania in the east. The mantled guereza lives in both deciduous and evergreen forests. It mainly inhabits forest and savannah woodlands and often extend into highland and montane forests. It can be found in other forest habitats, both primary and secondary, such as riparian, gallery, and upland forests. It is particularly common in forests close to rivers and lakes and at high elevations. It can be found in elevations as high as. This species prefers secondary forests and selects them over old-growth forests if given the choice. It is likely that the mantled guereza prefers these forests due to the increased number of food trees and the weaker chemical defenses of the species within. The mantled guereza is sometimes found in swamps as well as human-made habitats such as Eucalyptus plantations, which may be frequented when the monkey has nutritional deficiencies.Ecology
The mantled guereza is primarily arboreal, but does sometimes descend on the ground to forage and travel, perhaps more so than most other colobines. It is diurnal and rests for up to half the day. Foraging or travelling are the next most common activity. Sometime after dawn, mantled guereza groups leave their sleeping trees and will return to them at dusk. During the day, the mantled guereza has long rest periods in between periods of moving and feeding. Other activities, including grooming, greeting, playing and being vigilant, are performed to a lesser extent.Despite its reputation as an exclusive leaf-eater, the mantled guereza is not an obligate folivore. While it mainly eats leaves and fruit, its diet is quite variable. It may eat bark, wood, seeds, flowers, petioles, lianas, aquatic-plants, arthropods, soil, and even concrete from buildings. The amount of each food item in its diet varies by area and time of year. Nutritional factors like protein, tannins, and sodium levels in leaves influence its food choices. It may even intermittently travel longer distances to access plants with higher levels of nutrition. Leaves usually make up over half of its diet, although fruits are occasionally eaten more depending on the season. When foraging for leaves, the mantled guereza prefers young ones over old. With fleshy fruits, the mantled guereza prefers to eat them unripe, which may serve to reduce competition with primates that eat ripe fruits. It consumes a number of plant species but only some make up most of its diet at a specific site.
Like all colobi, the mantled guereza is able to digest leaves and other plant fibers with a large, multi-chambered stomach that contains bacteria in certain areas. Like most colobines, it prefers foods with high fiber content that can be easily extracted with its specialized stomach. The mantled guereza is mostly preyed on by the crowned hawk-eagle, but it is also eaten by other birds of prey such as Verreaux's eagle. The common chimpanzee is known to hunt the guereza. The leopard is another possible predator.