The black colobus is a tree-dwelling monkey that lives in small troops of 6 to 15 individuals, including one or more adult male (4). The majority of the diet consists of seeds and unripe fruits, but the black colobus also consumes leaves (6), as all colobus monkeys possess an unusual stomach that enables them to digest leaves more efficiently than other primates (2). The distinct high-pitched roar of the colobus can be heard across the forest as dawn breaks (3), and groups can also be heard calling to each other as they prepare to move or as they arrange their night-time sleeping positions (2).

The black colobus is one of the most threatened primate species in Africa (3). It is a large, heavily built monkey, with a glossy black coat and longer hair around the face and shoulders (2) (4). The hairs on its crown are semi-erect and point forward on the forehead (2). A unique feature of all Colobus monkeys is the reduced thumbs, in fact Colobus means 'docked' in Greek. As they leap through the forest habitat, the vulnerability of the thumb to injury is thought to outweigh the advantages of retention (2). Unlike all other species from the Colobus genus, in which the infant is born with a pure white coat, black colobus infants have brown coats (3).

This species is found from Cameroon (south of the Sanaga River), through Equatorial Guinea, western and central Gabon inland to Lope National Park (Brugiere 1998) (and with unconfirmed reports of sparse populations east of the Ogooue and Ivindo Rivers), parts of Congo, and on Bioko Island. This species is now rare or absent in those parts of its range where there has been extensive logging. In mainland Equatorial Guinea, for example, its range had been reduced to one-third of its former size by 1967. It is thought to occur from 500-2250 m asl.

There are two subspecies: C. s. satanas is found only on Bioko Island (Equatorial Guinea), while C. s. anthracinus is found in Cameroon south of the Sanaga River, Equatorial Guinea, Congo and Gabon.

Black colobus (Colobus satanas) are restricted to a small range in western Africa stretching from the Sanaga River in Cameroon, south through Equatorial Guinea and western and central Gabon. Their range extends as far east as the northwestern corner of Congo and as far west as Bioko Island, off the coast of Cameroon. There are two recognized subspecies. Colobus satanas satanas occupies Bioko Island, and C. s. anthracinus occupies the mainland.

Biogeographic Regions: ethiopian (Native )

Historic Range:
Equatorial Guinea, People's Republic of Congo, Cameroon, Gabon

Occurs in central-western Africa. There are two subspecies of the black colobus. The Gabon, or 'mainland', black colobus (C. s. anthracinus) occurs in Equatorial Guinea, east and south-west Cameroon, and Gabon, as far inland as Lope National Park. It may also occur in west Congo. The Bioko black colobus (C. s. satanas) is found only on Bioko Island, Equatorial Guinea (1) (5).

Due to the lack of white fur on their head, body, and tail, black colobus are easily differentiated from other species in the genus Colobus. They have black, glossy coats with dark skin underneath. Young are born with brown fur, which is replaced by the characteristic black fur within a few months after birth. Like all members of the family Colobinae, black colobus have a slender build, large salivary glands, and ischial callosities (tough, hairless, nerveless pads covering the rump). They lack opposable thumbs and only a small, nailed remnant remains. They have long fingers and limbs, with back legs that are generally longer than their arms. Compared to the largely folivorous guereza, black colobus have more robust skulls and larger, flatter teeth to facilitate seed crushing. On average, adult males are larger than adult females. Adults range in mass from 4 to 14 kg, with an average of 11 kg. Head and body length ranges from 50 to 70 cm long, and their tails range from 62.5 to 88 cm long.

Range mass: 4 to 14 kg.

Average mass: 11 kg.

Range length: 50 (head/body); 62.5 (tail) to 70 (head/body); 88 (tail) cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Habitat and Ecology

Systems

• Terrestrial

Black colobus spend a majority of their time high in the upper canopy of primary and mature secondary rainforests. They prefer areas of forest with an abundance of tree nuts and young leaves and have large home ranges. They occasionally descend from the high branches to feed on fallen nuts, but generally remain in the canopy.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: rainforest

The black colobus inhabits dense primary rainforest, as well as mature secondary rainforest, montane and swamp forest, and may also occasionally be found in coastal sand dunes and wooded meadows (4) (5).

Black colubus are primarily granivorous and a majority of their diet consists of hard seeds and nuts. Their specialized molars have large crushing surfaces, which are thought to be an evolutionary adaptation to granivory. In addition to nuts and seeds, black colobus eat unripe fruit and leaves, particularly young leaves from lianas (i.e., long-stemmed woody vines rooted in soil). When seeds and young leaves are scarce, black colobus feed primarily on mature leaves. Like all Colobus species and similar to most ungulates (i.e., Perissodactyla and Artiodactyla), black colobus have four-chambered stomachs containing bacterial communities that help break down cellulose. Studies have shown that their preference for seeds is not contingent upon leaf quality or tree diversity throughout their home range.

Plant Foods: leaves; seeds, grains, and nuts; fruit

Primary Diet: herbivore (Granivore )

Because black colobus are seminomadic granivores, they are important seed predators and likely important seed dispersers as well. Dropped seeds and fruits likely serve as an important food source for terrestrial species such as red river hogs.

Ecosystem Impact: disperses seeds

Humans are the primary predator of black colobus, as these monkeys are often hunted for bushmeat. Although information on other predators is not readily available, leopards and eagles are known to prey upon other species of Colobinae. The high-pitched roar of black colobus may be used as an anti-predator defense mechanism.

Known Predators:

• Humans (Homo sapiens)

Colobus satanas is prey of:
Homo sapiens
Panthera pardus
Stephanoaetus coronatus

This list may not be complete but is based on published studies.

Black colobus have one of the most distinctive calls of all African primates. The loud, is thought to be multifunctional and may be used during male-male competition, maintaining group spacing, defending territory, or intimidating predators. They have tri-color vision and rely primarily on sight to perceive their environment.

Communication Channels: acoustic

Perception Channels: visual ; acoustic

There is no information available regarding the average lifespan of Colobus satanas.

Little is know of mating behavior in black colobus. They are generally polygynous and tend to live in groups consisting of both males and female. Typically, they mate with individuals in their own group, and male-male competition for mates may occur.

Mating System: polygynous

Black colobus can breed year-round. Although this species has not been studied extensively in captivity, their close relative, guerezas, give birth throughout the year. Only red colobus and olive colobus are known to have birth seasonality. Male black colobus reach sexual maturity around 6 years of age, while females reach sexual maturity by 4 years of age. Menstruation lasts approximately 1 month and is marked by visible menstrual bleeding. Once pregnant, gestation lasts for 200 days. Although single births are most common, twins are possible on rare occasions.

Breeding season: Black colobus breed year-round.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Average gestation period: 200 days.

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

Little is know of parental care in Colubus satanas. Because they are polygynous, it is thought that females provide a majority of parental care.

Parental Investment: female parental care

Year Assessed

Assessor/s

Reviewer/s

Justification

History

• 2000
  Vulnerable
• 1996
  Vulnerable
• 1994
  Vulnerable
  (Groombridge 1994)
• 1990
  Endangered
  (IUCN 1990)
• 1988
  Endangered
  (IUCN Conservation Monitoring Centre 1988)
• 1988
  Endangered
• 1986
  Vulnerable
  (IUCN Conservation Monitoring Centre 1986)

Black colobus are classified as vulnerable on the IUCN's Red List of Threatened Species. Major threats to their persistance are hunting for the bush meat trade and habitat destruction due to agriculture and logging. Population size has decreased by 30% over the past thirty years and as much as 60% on Bioko Island due to habitat loss and hunting. Black colobus have become locally extinct in areas particularly vulnerable to logging.

CITES: appendix ii

IUCN Red List of Threatened Species: vulnerable

Current Listing Status Summary

Status: Endangered
Date Listed: 10/19/1976
Lead Region: Foreign (Region 10) 
Where Listed:


Population detail:

Population location: entire
Listing status: E

For most current information and documents related to the conservation status and management of Colobus satanas , see its USFWS Species Profile

Classified as Vulnerable (VU) on the IUCN Red List (1). Colobus satanas satanas (Bioko black colobus) is classified as Endangered (EN) and Colobus satanas anthracinus (Gabon black colobus) is classified as Vulnerable (VU) (1).

Population

Population Trend

Major Threats

Numbers of black colobus monkeys are declining, the result of both hunting and habitat destruction (3). The black colobus is a popular target for hunters, and is widely hunted with shotguns or bows and arrows (6). On Bioko Island, where bushmeat is a vital source of protein and cash for the locals, surveys indicate that the black colobus is becoming scarcer and is probably being hunted to dangerously low numbers (7). The black colobus appears to be more sensitive to habitat disturbance than other Colobus species and is rare or absent in forests that have been logged (3). This has resulted in the black colobus disappearing from many areas (8). Even protected areas in which the black colobus occurs are not safe from habitat degradation; for example, the Gamba Reserve complex is being impacted by unsustainable logging, agriculture and oil exploration (3) (9).

Conservation Actions

The Gabon black colobus occurs in a number of protected areas, including Dja and Douala-Edea Reserves in Cameroon, Lopé National Park, Gabon, Monte Alen National Park in Equatorial Guinea, and the Gamba Reserve complex in Gabon (3) (5) (10) (11). The Bioko black colobus population is found entirely within two protected areas on Bioko Island, Pico Basile National Park and the Gran Caldera and Southern Highlands Scientific Reserve. However, these areas may offer little actual protection (5), and the subspecies is reported to have undergone the largest decline of all primates on the island, now being rare outside the Gran Caldera (1) (12). In 1986, the IUCN/SSC Primate Specialist Group compiled an Action Plan for African Primate Conservation in which a number of measures were outlined for the conservation of the black colobus. This plan was revised and the conservation recommendations reviewed in a 1996 publication. Further actions suggested included continued efforts to survey and develop the Dja Reserve and fully protect a core area of the Lopé Reserve. In addition, it was recommended that a management plan was developed for the Gamba Reserve complex, which included measures to reduce the impact of oil exploration occurring in the area (3). Working with local people in Bioko Island to find alternatives to bushmeat is also an urgent priority (7), to ensure the continued survival of the endangered Bioko black colobus.

There are no known adverse effects of black colobus on humans.

Black colobus monkeys are commonly hunted for their meat and fur.

Positive Impacts: food ; body parts are source of valuable material