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 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).

This widespread species ranges from the area of the Donga River region of Nigeria and the Yabassi District of Cameroon, eastwards across the Oubangui River from the Central African Republic to the northern Democratic Republic of the Congo, and then discontinuously eastwards to southern Sudan, Uganda, the Kenyan and Ethiopian highlands, and Mount Kilimanjaro, Mount Meru and the Kahé District of Tanzania (Groves in press).

There are eight subspecies:

The subspecies C. g. occidentalis occurs from eastern Nigeria, Cameroon and Gabon, eastwards to south-western Sudan and Uganda.

The nominate C. g. guereza is found in forested areas of the Ethiopian highlands west of the Rift Valley and down into the lowland reaches along the Awash River, the Omo River and in the Blue Nile gorge.

C. g. gallarum is restricted to the Ethiopian highlands east of the Rift Valley.

The subspecies C. g. dodingae is endemic to the Didinga Hills in south-eastern Sudan.

C. g. matschiei is found in Kenya west of the Rift Valley, and also in some of the forests within the Rift, west to Mount Elgon (Kenya and Uganda), and south to the Ngorongoro Crater and the Grumeti River in Tanzania.

C. g. percivali is restricted to the Matthews Range of Kenya.

C. g. kikuyuensis is known only from the Ngong Escarpment, Mount Kenya and the Aberdare Mountain Range, Kenya.

C. g. caudatus is present on montane forests of Mt. Kilimanjaro and Mt. Meru, and the adjoining forests at slightly lower altitudes (Kahe; Momela Lakes in Arusha National Park), Tanzania and Kenya.

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 )

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).

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.

Habitat and Ecology

Systems

• Terrestrial

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

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).

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 )

As herbivores which serve as prey for several other species, these monkeys may play an important role in food webs.

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:

• crowned hawk eagles
• leopards
• chimpanzees

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 ; acoustic

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.

Maximum longevity: 35 years (captivity) Observations: One wild born female lived 31.6 years in captivity, making her nearly 35 years old (Richard Weigl 2005).

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); 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

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There are 2 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
 

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Species: 4
Species With Barcodes: 1

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

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).

Population

Population Trend

Major Threats

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).

Conservation Actions

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).

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)