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Colobus angolensisAngolan colobus

By Brandon Thompson

Geographic Range

Angolan colobus monkeys are found from eastern Nigeria through Cameroon, eastern Gabon, northern Congo, the central African Republic, northeastern Zaire, Uganda, Ruanda, Ethiopia, Kenya, and northern Tanzania (Grzimek, 1990). (Grzimek, 1988)

Habitat

Angolan colobus monkeys are found in various habitat types such as gallery, montane, lowland, and bamboo forests. They are also found in savannas and swamp lands. This species inhabits primary and secondary lowland to montane forest up to 3000m (Rowe, 1996; Grzimek, 1990).

  • Range elevation
    3000 (high) m
    9842.52 (high) ft

Physical Description

Colobus monkeys are medium-sized, arboreal monkeys with slender bodies and long tails. The five recognized species of Colobus share the following characteristics: a reduced thumb, prominent rump callosities, and a complex stomach which aids in the digestion of cellulose. Angolan colobus monkeys have long, silky hair. They are black with a white brow band, cheeks, and throat. They have long-haired white epaulettes on the shoulders and the lower half of the tail is white. The tail length is 706 mm for females and 829 mm for males and head and body length ranges from 490 to 680 mm. Mass varies between 6 and 11.4 kg, with males slightly larger than females. Young are born completely white and begin changing to their adult pelage at about three months of age (Rowe, 1996; Grzimek, 1990; Wisconsin Primate Research Center, 2000). (Grzimek, 1988; Rowe, 1996; Wisconsin Primate Research Center, April 12, 2000)

  • Sexual Dimorphism
  • male larger
  • Range mass
    6.1 to 11.7 kg
    13.44 to 25.77 lb
  • Average mass
    8.90 kg
    19.60 lb
  • Range length
    49 to 68 cm
    19.29 to 26.77 in

Reproduction

Colobus angolensis is polygynous. Dominant adult males control reproductive access to the females within their family group. Younger males from within the group or from other groups may periodically replace the dominant male. Females of the family group mate with the dominant male.

In most Angolan colobus social groups there is one adult male present with about 2 to 6 females. Larger groups generally have more than one resident male. A behavior called presenting is performed by the female to communicate to the male that she is ready for copulation (Estes, 1991; Nowak, 1999). The gestation period ranges from 147 to 178 days and a single offspring is generally born, though twins are possible. In this species, the infants are born all white and start changing color at about 3 months old. Young are not weaned until they are about 15 months of age. Males reach sexual maturity in four years, females in about two years (Grzimek, 1990). (Estes, 1991; Grzimek, 1988; Nowak, 1999)

  • Breeding interval
    It is likely that females are capable of producing offspring ever two years.
  • Breeding season
    There is no distinct breeding season.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1.00
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    147 to 178 days
  • Average weaning age
    15 months
  • Range age at sexual or reproductive maturity (female)
    2 to 4 years
  • Range age at sexual or reproductive maturity (male)
    2 to 4 years

Young Colobus monkeys are cared for by their mothers and by other members of the social group. The infants are weaned in about 15 months.

  • Parental Investment
  • altricial
  • 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
  • extended period of juvenile learning

Lifespan/Longevity

Angolan colobus monkeys can live for 20 years in the wild and up to 30 years in captivity (Grzimek 1990).

  • Range lifespan
    Status: wild
    20 (high) years
  • Range lifespan
    Status: captivity
    30 (high) years

Behavior

Angolan colobus monkeys are diurnal and arboreal. They occasionally come to the ground near streams to eat herbaceous vegetation but prefer to remain higher in the canopy. They are the most arboreal of all African monkeys. These colobus monkeys live in troops of up to 25 individuals, although temporary gatherings of over 300 have been observed. They typically live in relatively small social groups of one adult male and normally two to six females with offspring. Young males in the group are forced to leave before they reach breeding age but may also challenge the dominant male for control of the females. When a troop is threatened by a predator, the male jumps and roars until the rest of the troop has fled (Rowe 1996, Fimbel 2001). Groups defend a relatively small core home range from other troups of Colobus monkeys. Morning roaring contests between dominant males may help to maintain group spacing (Nowak, 1999).

Communication and Perception

Food Habits

Angolan colobus monkeys are primarily folivorivous, although they also feed on stems, bark, flowers, buds, shoots, fruits, some aquatic plants' fruits and insects. They are also known to eat clay from termite mounds. In many parts of their range, young leaves of the hackberry tree are the food of choice. They can eat up to two to three kilograms of leaves a day and normally feed in the morning and evening (Rowe 1996, Estes 1991).

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • wood, bark, or stems
  • fruit
  • flowers

Predation

Angolan colobus monkeys are diurnal and highly arboreal, which may help avoid predators that feed at night. They are also able to avoid predators by maneuvering quickly through the trees and by group members joining together to defend themselves (Sanders 2000, Grzimek 1990).

Ecosystem Roles

This species provides food for some large predators, such as eagles and large cats. They may disperse seeds of the fruits they eat.

Economic Importance for Humans: Positive

Angolan colobus monkeys benefit the people of Africa by providing them with meat and skins. They also attract ecotourism activities and have been used in research (Von Hippel 2000).

Economic Importance for Humans: Negative

Although all primate species may harbor diseases that can be passed to humans, Angolan colobus monkeys do not have significant negative impacts on humans.

Conservation Status

Angolan colobus monkeys are not considered endangered and may be fairly abundant in parts of their range. However, they are vulnerable to habitat destruction and have suffered extensively by hunting for bushmeat and skins, especially in highly populated areas. Populations are declining fairly rapidly in some areas such as the Kakamega forest in Kenya (Von Hippel 2000, Grzimek 1988).

Other Comments

Colobus is derived from a word meaning "mutilated one" because, unlike other monkeys, Colobus monkeys lack thumbs.

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Brandon Thompson (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nomadic

generally wanders from place to place, usually within a well-defined range.

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Estes, R. 1991. The Behavior Guide to African Mammals. Berkeley and Los Angeles, California: Univeristy of California Press.

Fimble, C. 2001. An Ecological basis for large group size in *Colobus angolensis* in the Nyungwe forest, Rwanda. African Journal of Ecology, 39: 83-92.

Grzimek, B. 1988. Grzimek's Encyclopedia of Mammals. Munchen, West Germany: Mcgraw-Hill.

Macdonald, D. 1984. The Encyclopedia of Mammals. New York, N.Y.: Oxford Ltd.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore, Maryland: The Johns Hopkins University Press.

Rowe, N. 1996. The Pictorial Guide to the Living Primates. East Hampton, New York: Pogonias Press.

Sanders, W., J. Mitani, M. Teaford. 2000. Taphononic aspects of eagle predation of primates from kibale forest, Uganda. American Journal of Physical Anthropology, 30: 267-268.

Von Hippel, F., H. Fredrick, E. Cleland. 2000. Population decline of the black and white colobus monkey in the Kakamega forest, Kenya. Zoologica Africana, 35: 69-75.

Wisconsin Primate Research Center, April 12, 2000. "Primate Info Net: Angolan Black-and-White Colobus Monkey (Colobus angolensis)" (On-line). Accessed August 31, 2002 at http://www.primate.wisc.edu/pin/factsheets/colobus_angolensis.html.

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