Guereza (Colobus guereza)
|Also known as:||Eastern black-and-white colobus, magistrate colobus|
|French:||Colobe À Épaules Blanches, Colobe De L'Abyssinie, Colobe Guéréza|
|Spanish:||Colobo Rojo Guereza|
|Size||Male weight: 9.3 - 13.5 kg (2)|
Female weight: 7.8 - 9.2 kg (2)
Male head-body length: 54.3 - 69.9 cm (2)
Female head-body length: 52.1 - 67.3 cm (2)
Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES (2). Subspecies: Colobus guereza caudatus (Mt. Kilimanjaro guereza), C. g. kikuyuensis (Mt. Kenya guereza), C. g. guereza (Omo River guereza) and C. g. occidentalis (Western guereza) classified as Least Concern (LC) on the IUCN Red List. C. g. gallarum (Djaffa Mountains guereza), C. g. dodingae (Dodinga Hills guereza) and C. g. matschiei (Mau Forest guereza) classified as Data Deficient (DD) on the IUCN Red List. C. g. percivali (Mt. Uaraguess guereza) classified as Endangered (EN) on the IUCN Red List (1).
The guereza is a large, sturdy colobus monkey with an attractive black-and-white coat (2) (4). Glossy, black fur covers much of the body, but contrasts with short, white hair surrounding the face, a u-shaped, cape-like mantle of long white hair that extends down the shoulders and across the lower back, and a bushy white tuft to the tip of the tail (2) (4) (5) (6). Although not clearly resolved, eight guereza subspecies are currently recognised, each occupying a distinctive range and exhibiting slight variations in appearance. The main features that set the subspecies apart are the length and colouration of the mantle, which sometimes appears creamy or yellow, the length of the tail, and the extent of the tail tuft. At birth, the hair of infant guerezas is completely white, in striking contrast with the predominately black fur of the adult guereza (2).
The guereza has a relatively widespread, central African distribution, extending from Nigeria, Cameroon and Gabon in a band eastwards across to Ethiopia, Kenya and Tanzania (1) (2).
The guereza is found in a wide range of wooded habitats, including all types of closed canopy forests up to an altitude of 4,500 metres, gallery forest and wooded savannah, with a particular preference for degraded or secondary forest (1) (2) (4) (5).
Guerezas generally live in small, cohesive groups, typically ranging in size from 3 to 15 individuals, but occasionally up to as many as 23 (2) (7). These social groups sometimes support several adult males, but normally comprise one adult male, accompanied by several adult females and juveniles. Despite being a diurnal species, the guereza spends over half the day resting, with the remaining hours of daylight devoted mostly to feeding and moving about. When active, this primarily arboreal species can be seen bounding through the canopy, leaping the gaps from tree to tree. The guereza sleeps during the night, with a single group generally occupying several adjacent trees nearby a source of food. To communicate, the guereza employs various vocalisations, the most distinctive of which is an impressive roar usually made by the dominant adult male and echoed by males in neighbouring groups (2). These roaring bouts, which usually take place during the night or at dawn, are thought to play a role in male-male competition and help maintain spacing between groups (2) (7).
Leaves and fruit are the main constituents of the guereza’s diet (2). In order to derive adequate nutritional value from leaves, the guereza, like other colobus monkeys, has evolved a large, multi-chambered stomach, capable of digesting enormous amounts of foliage, with the help of gut microbes that efficiently break down cellulose (2) (5) (6). The guereza itself is a source of food for several predators including crowned hawk-eagles, chimpanzees and possibly leopards (2).
Reproduction takes place at all times of the year, with the adult male, or dominant male in multi-male groups, normally having exclusive access to the females members of the group. After a gestation period lasting just over five months, the female usually gives birth to a single white-haired infant. For the first few months of an infant’s life, it is the focus of the group’s attention, and is frequently handled, particularly by the females. When moving about during this time, the infant always hangs onto the fur of its mother’s chest, but after around 20 weeks becomes more independent, and after 50 weeks no longer clings to its mother or suckles (2).
The guereza remains relatively widespread and abundant, and, owing to its tolerance of forest degradation, is considered to be one of the least threatened species of colobus monkey (1) (2). However, while the species as a whole is a low priority for conservation, several subspecies are in a more precarious state than others. Clearance of forests for agriculture is a major concern for some guereza populations, particularly those belonging to the subspecies C. g. gallarum and C. g. matschiei, both of which have a relatively small range in East Africa. Unfortunately, in the absence of recent survey work, it is not known how much pressure these populations are under. Consequently, both subspecies are currently listed as Data Deficient on the IUCN Red List, as is C. g. dodingae which was last recorded in the 1960s. The persecution of guereza for bushmeat and pelts is an additional threat in parts of its range. In particular, commercial trade in guereza skins is believed to be putting C. g. percivali, the only subspecies classified as Endangered, at considerable risk of extinction (1).
A priority for guereza conservation is to carry out further research to resolve the uncertain taxonomic status of the different subspecies, and to accurately determine the conservation status of those subspecies currently classified as Data Deficient (1). Work is currently underway to collect baseline data on C. g. percivali in Kenya, which will establish appropriate conservation initiatives for this Endangered guereza (8). Fortunately for the species as a whole, not all guereza populations are under significant threat and many occur within protected areas (1).
For further information on the guereza and this species’ conservation see:
- Primate Info Net:
Authenticated (13/03/09) by Dr Peter J. Fashing, Assistant Professor, Department of Anthropology, California State University, Fullerton.
- Arboreal: an animal which lives or spends a large amount of time in trees.
- Gallery forest: forest growing adjacent to a watercourse in an area otherwise treeless.
- Gestation: the state of being pregnant; the period from conception to birth.
- Secondary forest: forest that has re-grown after a major disturbance, such as fire or timber harvest, but has not yet reached the mature state of primary forest.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
IUCN Red List (July, 2014)