First seen by Ruppell in 1835, black and white monkeys have been widely studied. When the range of guerezas overlaps with that of red colobus monkeys, guerezas feed from fewer species of trees (usually less than half of the usual number) and choose different plant parts. Their tolerance of a less varied diet allows them to occupy forests or thickets with impoverished or specialized flora. Their sacculated stomachs and highly efficient extraction of nutrients from their food allow them to survive on a less nutritious diet than monkeys lacking bacterial fermentation. Natural enemies of the guereza are crowned hawk eagles, leopards, and sometimes chimpanzees. If guerezas are able to live a life absent of predator threat, longevity is about 20 years (29 years in captivity).
An interesting fact about Kenyan guerezas living in high altitudes is that albinism is frequent, but for unknown reasons.
Colobus means "mutilated one". The name was given to these monkeys because they have no thumbs.
(Bateman, 1984; Grzimek, 1988; Happold, 1987; Nowak, 1991)
Male guerezas roar loud nocturnal and dawn choruses as a means of spacing groups. Five vocal sounds have been recorded: roars, snorts, purrs, honks, and screams.
In addition to vocal communication, visual signals, such as flapping of fringe fur, facial expression, and body posture are used in aggressive communication between groups.
Tactile communication in this species includes grooming, playing, and fighting.
(Bateman, 1984; Grzimek, 1972; Grzimek, 1988; Happold, 1987; Nowak, 1991; The Phoenix Zoo)
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
There has been a drastic decline in Colubus populations over the last 100 years. Guerezas are noted in Appendix II of the Concentration in International Trade of Endangered Species (CITES). Population sizes of black and white monkeys are currently declining in many localities due to hunting and deforestation by humans. Nevertheless, since 1934 it has been reported that guerezas are "not uncommon" in suitable protected habitats. For example, guerezas are still abundant in most parts of their lowland ranges in Cameroon and the Nigerian border, and in East African reserves and parks. Although guerezas are still abundant, there is the potential for extinction of eastern populations from unrestricted skin trading.
(Honacki, 1982; Happold, 1987; Kingdon, 1987; Metro Washington Park Zoo, 1995; http://www.aza.org/aza/ssp/colmonk.html 1996)
US Federal List: no special status
CITES: appendix ii
IUCN Red List of Threatened Species: least concern
These monkeys do not really initiate contact with humans. Therefore, the only negative effects from these black and white monkeys are the few instances when guerezas eat agricultural crops, probably due to inhospitable environmental conditions.
(Grzimek, 1988)
Negative Impacts: crop pest
Guerezas are used in animal testing concerning human diseases, behavior, and physiology. For example, studies have been performed that test for certain behavioral responses when the territory of a guereza group is threatened. Another study tested the effects of rickets (vitamin-D deficiency) on guerezas. Other studies deal with how phenotypic variability is inversely related to selection intensity. A final example is a study dealing with the effects of an experimental serum for Mycobacterium bovis. The data collected in these studies has proved invaluable.
Colobus guereza is one of many monkey species that is sacred to the Hindu and Buddhist religions. They play a major role in these religions as icons of sacred gods.
Colobus guereza fur has been a luxury for people in some cultures and has brought in large amounts of money to trade and fur companies.
(Grzimek, 1988; Morrisey, 1995; Stetter, 1995; Suedmeyer, 1996; Von-Hippel, 1996)
As herbivores which serve as prey for several other species, these monkeys may play an important role in food webs.
Guereza are the second most folivorous of the Colobus species. Their diet consists primarily of leaves (especially from Celtis durandii, or Hackeberry Tree) with about 58% of young unripe leaves, 12.5% mature leaves, 13.5% fruits, 4% leaf buds, and 2% blossoms. However, this distribution is highly varied seasonally and geographically; thus at times mature leaves may account up to 34% of the diet. Guerezas seem to prefer leaves that are less susceptible to seasonal fluctuations. Guereza get water from dew and the moisture content of their diet, or rainwater held in the tree trunk hollows. In captivity C. guereza is fed monkey chow, fruits and vegetables.
Natural enemies of the guereza are crowned hawk eagles, leopards, and sometimes chimpanzees.
(Bateman, 1984; Grzimek, 1988; Kingdon, 1987; Metro Washington Park Zoo, 1995; Nowak 1991, http://www.aza.org/aza/ssp/colmonk.html)
Plant Foods: leaves; fruit; flowers
Primary Diet: herbivore (Folivore )
Colobus guereza is found in diverse regions of equatorial Africa. This species is found in the lowland tropical rainforest to the upper reaches of the Montane forests of the upper Donga river and tributaries, as well as Acacia-dominated riverine galleries and evergreen thicket forests. Guerezas are also found in the equatorial areas of Africa including Nigeria, east and west of the Niger river, and locally distributed in relic forests north of the rainforest zone. They are also found along the Donga river, Gashaka, Ngelnyaki, Cameroon, Ethiopia, Gojjam, Kulla, Kenya, Uganda, Tanzania, N Congo, E Gabon, Central African Republic, NE Zaire, W Kenya, NW Rwanda, and S Sudan.
(Bateman, 1984; Grzimek, 1988; Happold, 1987; Honacki, 1982; Kingdon, 1987; MacDonald, 1984; Nowak, 1991)
Biogeographic Regions: ethiopian (Native )
Guerezas live in forest, woodlands, or wooded grasslands. They can also survive in dry, moist, or riparian forests that are either in lowlands or up to 3,300 m. They are most abundant in secondary forests or along rivers. They tend to live in the lower part of the trees if their area does not overlap with that of any other group of monkeys. When trees are not densely spaced, guerezas feed and travel on the ground.
(Bateman, 1984; Grzimek, 1988; Happold, 1987; MacDonald, 1995; Nowak, 1991)
Range elevation: 3,300 (high) m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest ; scrub forest
Other Habitat Features: riparian
A member of the related species Colobus polykomos is reported to have lived 23.5 years in captivity. The lifespan of C. guereza is similar, throught to be about 29 years in captivity and about 20 years in the wild.
(Bateman, 1984; Grzimek, 1988; Nowak, 1991)
Range lifespan
Status: wild: 20 (high) years.
Range lifespan
Status: captivity: 29 (high) years.
Average lifespan
Status: captivity: 24.0 years.
Average lifespan
Sex: male
Status: captivity: 24.5 years.
Average lifespan
Sex: female
Status: captivity: 23.8 years.
Colobus guereza is a heavy bodied animal with a long tail. The head and body length is 45 to 72 cm and the tail length is 52 to 100 cm. Guerezas are slightly sexually dimorphic in that the males can weigh up to 1.19 times more than females. Guerezas have only four digits on each hand; the thumb is absent or represented by a small phalangeal tubercle that sometimes bears a nail. The loss of the thumb may be an adaptation for quick movements through the trees.
Members of the genus Colobus, which are in the subfamily Colobinae, are distinguished from members of the other subfamily, Cercopithecinae, by the absence of cheek pouches and the presence of prominent ischial callosities that are separate in females and contiguous in males.
The stomach of C. guereza is complex. It is subdivided by a partition into 2 subregions. The upper region contains a neutral medium, which is necessary for the fermentation of foliage by anaerobic bacteria. The black and white monkeys' large salivary glands provide a buffer fluid between the two regions of the stomach.
The coloration of fur is distinctly black and white. The face is gray and has no fur. The coat is glossy black, and the face and callosities are surrounded by white. A U-shaped white mantle of varying length is found on the sides. The outside of the thigh is variably whitish, and the tail is either a whitish or yellowish color from tip to base. There is also a large white tuft at the end of the tail.
The skull is prognathous, that is, the lower jaw projects beyond the upper. The orbits are relatively small and oval with narrow superciliary ridges. A postorbital bar forms a plate on the side of the skull separating the orbit from the temporal fossa. The nostrils are more or less lengthened by an extension of nasal skin, and the nose nearly touches the mouth.
The molar teeth have high pointed cusps, and the inside of the upper molars and the outside of the lower molars are slightly convexly buttressed. The enamel on the inside of the lower incisors is thick, and there is a lateral process on the lower second incisor.
The young of the C. guereza do not share the black and white coloration, but instead have pure white fur for the first weeks of their life.
(Bateman, 1984; Grzimek, 1972; Grzimek, 1988; Happold, 1987; Honacki, 1982; Kingdon, 1987; MacDonald, 1984; Nowak, 1991)
Range mass: 5 to 14 kg.
Range length: 45 to 72 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average basal metabolic rate: 17.037 W.
Natural enemies of guerezas are crowned hawk eagles, leopards, and sometimes chimpanzees.
(Bateman, 1984; Grzimek, 1988; Kingdon, 1987; Metro Washington Park Zoo, 1995; Nowak 1991, http://www.aza.org/aza/ssp/colmonk.html)
Known Predators:
Guerezas have a polygynous mating system.
Mating System: polygynous
There seems to be little or no reproductive seasonality in most populations of Colobus monkeys that have been studied, but there tends to be a birth peak, timed so that weaning coincides with the greatest seasonal abundance of solid food. The age of full sexual maturity in the guerezas is at least 6 years in males and 4 years in females. Each adult female produces one young every 20 months after a gestation period of about 6 months.
Sexual behavior is usually initiated by the female by tongue smacking. During copulation, the female remains prone.
(Bateman, 1984; Grzimek, 1988; Metro Washington Park Zoo, 1995)
Breeding interval: Guerezas breed once every two years.
Breeding season: Breeding is not strictly seasonal, although births are timed so that weaning occurs at the time of greatest food availability.
Average number of offspring: 1.
Average gestation period: 6 months.
Average age at sexual or reproductive maturity (female): 4 years.
Average age at sexual or reproductive maturity (male): 6 years.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 397.8 g.
Average gestation period: 175 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (male)
Sex: male: 2192 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1461 days.
At birth, the infants are about 20 cm in head-body length and weigh about 0.4 kg. The eyes are open and the infant clings to the mother's or father's stomach. The weaning age is not known. Both the female and the male take part in the parenting of the child. Female guerezas remain in their natal group. This means that mothers and daughters have life-long relationships.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning; inherits maternal/paternal territory
