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Colobus polykomosking colobus

By Devon Landes

Geographic Range

Individuals of the genus Colobus are typically found in tropical rain forests (lowland and montane types) of Africa, in the countries of Senegal, Ethiopia, Tanzania, Congo, Malawi, Uganda and Zambia. Colobus polykomos is limited to a range from Gambia to the Ivory Coast. (Davies and Oates, 1994)

Habitat

Most African forests in which C. polykomos is found experience prolonged and pronounced dry seasons. Most of the forest lies within 10 degrees of the equator and is characterized by two rainfall peaks interspersed with two relatively dry periods--one short and one long. Much of the African moist forest zone is dominated by a single leguminous tree species. At present, much of C. polykomos habitat has been overrun by farming (especially rice cultivation) and tree cutting. This being the case, these areas typically support a variable array of young secondary forest. The old secondary forest (60% of the habitat) is dominated by the leguminous trees.

Physical Description

Males, on average, weigh approximately 9.90 kg, whereas a typical female is near 8.30 kg. Head and body length range from 450 to 720 mm, tail length from 520 to 1,000 mm. Colobus polykomos has white markings like most other species within the genus Colobus, however, this species is distinctive in that the chest and whiskers are white while the rest of the body is black. Further, the tail is entirely white and not tufted (Nowak, 1999). Colobus polykomos is slender- bodied with a long tail and prominant rump callosities. A complex sacculated stomach is present, but cheek pouches are absent. The thumb is reduced to a mere tubercle, the skull is somewhat prognathous, and the orbits are oval with narrow superciliary ridges (Nowak, 1999). The nostrils are lengthened by an extension of the nasal skin and may extend to nearly the mouth. (Nowak, 1999)

  • Sexual Dimorphism
  • male larger
  • Range mass
    5 to 14 kg
    11.01 to 30.84 lb
  • Range length
    450 to 720 mm
    17.72 to 28.35 in

Reproduction

The mating system has been described as 'unimale'--one male mating with several females, as well as 'multimale' where multiple males mate with multiple females.

There is conflicting evidence regarding seasonality of reproduction. In some groups, C. polykomos has been observed to give birth year round, but in others the birth season coincides with the dry season (December-May). This is thought to occur as a result of the greater availability of fruit as well as access to crops and human provisioning.

The gestation period of this species is 175 days on average, and the interbirth interval is approximately 24 months. Females, on average, produce 1 offspring every 20 months (Nowak, 1999) and reach sexual maturity at approximately 2 years of age. (Nowak, 1999)

  • Breeding interval
    Colobus polykomos breed once every two years.
  • Breeding season
    Data on breeding seasonality is somewhat conflicting, with some populations breeding year round, and others breeding so that births occur during the rainy season.
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Average gestation period
    175 days
  • Average gestation period
    185 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    1642 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    730 days
    AnAge

As in all primates, females are primarily responsible for the care of offspring. Females provide their young with milk, protection, and grooming. Young are not able to walk immediately, and must be carried for some time. The role of males in parental care has not been reported. (Nowak, 1999)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • protecting
      • female

Lifespan/Longevity

The maximum longevity reported for this species is 23.5 years in captivity. Wild life spans are not known with certainty, but are likely to be lower than this.

Behavior

Colobus polykomos typically live in small social groups comprised of 3 to 4 adult females and 1 to 3 adult males. The females maintain close spatial relationships with one another and engage in grooming behavior. Adult males rarely interact and display a clear dominance hierarchy.

During the infrequent encounters between groups, adult males engage in aggressive displays with one another. Some of this aggression occurs in the form of territorial calling, which is meant to be indicative of male strength and condition. The calling can also be evoked in other situations, such as when a predator is threatening the group. Generally, however, it is thought that the main purpose of calling is to maintain spatial distance between two groups or between male members within one group.

Home Range

The range of C. polykomos averages 22 hectares with considerable overlap between groups.

Communication and Perception

Communication in most primates is complex, involving visual signals (such as facial expressions and body postures), vocalizations, and different forms of physical contact ( such reassurance gestures, aggression, grooming). It is likely that these monkeys employ all means of communication listed above. (Nowak, 1999)

Food Habits

Although C. polykomos is generally highly arboreal, members of this species are found to feed on the ground. Colobus groups typically have a daily foraging path of only about 500 meters. The diet consists mostly of leaves, but fruits and flowers can be more/less important depending upon the season (Nowak, 1999). (Nowak, 1999)

  • Plant Foods
  • leaves
  • seeds, grains, and nuts
  • fruit
  • flowers

Predation

Predators of these colobus monkeys are not reported. However, because of the size of these monkeys and their arboreal habits, likely predators include raptors and leopards. Large snakes might also take young animals.

Ecosystem Roles

These monkeys probably have some impact on their ecosystem. As a potential prey species, the abundance of these monkeys may affect the abundance of predators. In addition, their reliance on leafy vegetations, fruits and seeds, may affect the plant community, especially by dispersing seeds.

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

In the nineteenth century, C. polykomos was hunted by humans extensively for use of its fur . More recently, however, C. polykomos has provided little economic benefit for humans. They could be considered important in ways other than economically, however, due to the fact that they are ecologically, anatomically and socially interesting.

Economic Importance for Humans: Negative

Their numbers are so low as to have little to no effect on humans whatsoever.

Conservation Status

Colobus polykomos is considered to be highly endangered because of habitat destruction and hunting. Habitat destruction occurs through subsistance farming, commercial agricultural development and selective logging. Colobus polykomos is also extremely vulnerable to hunting by humans, both for their meat and fur.

Attempts at maintaining this species in captivity has largely failed, most probably because of their digestive peculiarities. Instead, it is important to manage C. polykomos habitat forests effectively and prevent any further habitat destruction in order to protect and conserve them.

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Devon Landes (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Ethiopian

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

World Map

acoustic

uses sound to communicate

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.

arboreal

Referring to an animal that lives in trees; tree-climbing.

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

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

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

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.

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.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

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.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

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.

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.

visual

uses sight to communicate

viviparous

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

References

Davies, G., J. Oates. 1994. Colobine Monkeys. New York: Cambridge University Press.

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

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