Cercopithecus neglectusDe Brazza's monkey

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Geographic Range

The range of Debrazza's monkey, Cercopithecus neglectus, is a large triangle bordered by southern Ethiopia to the Northeast, Cameroon to the Northwest, and northern Angola to the south. This species is more common in easten Africa and less regularly observed on the continent's western side. (Como Zoo and Conservatory, 2003; Oregon Zoo, 2005; Wolfheim, 1983)

Habitat

Debrazza's monkeys are found in forests, swamps, and seasonally flooded areas. They exist predominantly in the closed canopy, preferring dense vegetation, and are generally found within 1 km (.62 miles) of rivers in humid forests. (Oregon Zoo, 2005; Wolfheim, 1983)

Physical Description

This species shows marked sexual dimorphism in size. Male Debrazza's monkeys weigh up to 7 kg, three more than the average female, which weighs 4 kg. Lengths range from 40 to 63.5 cm. Females and males are gray with black extremities and tail. The shape of the head is round, with a long white beard, white muzzle, and an orange crown. The thighs and rumps have white stripes. Legs are long, and the tail is non-prehensile.

Male Debrazza's monkeys have a distinct blue scrotum. In addition, both males and females have well-developed cheek pouches and the most robust feet of all of the guenons. (Como Zoo and Conservatory, 2003; Oregon Zoo, 2005)

  • Sexual Dimorphism
  • male larger
  • Range mass
    4 to 7 kg
    8.81 to 15.42 lb
  • Range length
    40 to 63.5 cm
    15.75 to 25.00 in

Reproduction

The sexual dimporphism in size of this species suggests that breeding is probably polygynous. In most guenons, females remain in their natal group all of their lives, whereas males disperse around the time they reach sexual maturity. Males typically compete to control access to a group of females (Nowak, 1999). However, this species is reported to sometimes be found in pairs with young, indicating that there may be some monogamy (Oregon Zoo, 2005).

When it is time to mate, females solicit copulation by presenting themselves. During copulation, the female pouts by sticking her lower lip forward while keeping her lips closed. (Nowak, 1999; Nowak, 1999; Oregon Zoo, 2005)

Debrazza's monkeys reach sexual maturity at 5 to 6 years of age. The breedng interval is long, but the gestation period is 5 to 6 months. Single births are normal, although twins are produced on rare occasions. The known breeding season in the equatorial rain forest is from February to March. Otherwise, breeding occurs when food is available.

Becuase females nurse their young for a year, it is unlikey that females are able to produce more than one young per year, even under good conditions. Young begin to eat solid food around the age of 2 months. (Como Zoo and Conservatory, 2003; Napier and Napier, 1970; Oregon Zoo, 2005)

  • Breeding interval
    The exact breeding interval is not known.
  • Breeding season
    The known breeding season in the equatorial rain forest is from February to March.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    5 to 6 months
  • Average weaning age
    12 months
  • Range age at sexual or reproductive maturity (female)
    5 to 6 years
  • Range age at sexual or reproductive maturity (male)
    5 to 6 years

When born, the young are furred with eyes open. Newborns are able to cling to their mother's fur, but are comletely dependent upon her for food, comfort, grooming, and protection. Females nurse and care for their young until they become independent, sometime around the age of 1 year. Young females stay with their mothers a long as they live, whereas males leave when they are sexually mature.

The role of males in parental care has not been described. Although most parental care is clearly the responsibility of the mother, fathers may aid in protecting the young born to them in the social group from predators or from infanticidal males. Although infanticide has not been reported for this species, it does occur in other guenons. (Napier and Napier, 1970; Nowak, 1999; Oregon Zoo, 2005)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female
  • post-independence association with parents
  • extended period of juvenile learning

Lifespan/Longevity

The longevity of C. neglectus has not been reported, but other species within the genus Cercopithecus have been reported to live in excess of 30 years in captivity. Lifespans in the wild are likely to be somewhat shorter. It is reasonable to assume that Debrazza's monkeys are like the other members of their genus in regard to lifespan. (Nowak, 1999)

Behavior

Debrazza's monkeys are arboreal, territorial, and terrestrial. They take shelter in trees and freeze when alarmed. They are diurnal hand gatherers, foraging in the early morning and evening. Unlike some monkeys, they move around on all four feet. They are excellent swimmers.

Young males spend much of their time practicing being dominant by strutting around with arched tails and slamming branches, apparently imitating their father. While not always successful, the dominance of the resident male is sometimes challenged by another male monkey.

Group sizes are exceptionally small, consisting of 4 to 10 monkeys, though groups have been found with up to 35 members. Unlike some other species of guenons, Debrazza's monkeys are rarely found associating with other monkeys. However, in captivity, they associate more freely. Their predators are large African eagles, other primates, humans, and leopards. (Como Zoo and Conservatory, 2003; Nowak, 1999; Oregon Zoo, 2005; Proutkina, March 26, 2001)

Home Range

Home range sizes are not reported.

Communication and Perception

Communication between Debrazza's monkeys is both vocal and visual. Visual communication includes staring as a threat, sometimes with the mouth open but the lips covering the teeth. Another threat display is bobbing the head up and down. To reduce aggression in certain situations the lips are retracted showing clenched teeth. As an expression of tension or as another threat display, yawning by adult males is performed to show the canines.

Vocal communication consists of low boom calls to communicate territorialiy, and isolation calls often given by infant or juvenile monkeys when they become separated from the troop.

In addition to these, there is communication through tactile signals. These are likely to be especially important during mating, as well as between mothers and their offspring. (Como Zoo and Conservatory, 2003; Nowak, 1999; Oregon Zoo, 2005; Proutkina, March 26, 2001)

Food Habits

Debrazza's monkeys are omnivorous, but primarily eat fruit. Other items in their diet include leaves, flowers, mushrooms, beetles, termites, and worms. (Como Zoo and Conservatory, 2003; Nowak, 1999; Oregon Zoo, 2005)

  • Animal Foods
  • insects
  • terrestrial worms
  • Plant Foods
  • leaves
  • fruit
  • flowers
  • Other Foods
  • fungus

Predation

Like other small forest monkeys, it is likely that Debrazza's monkeys fall prey to chimpanzees, leopards, various avian predators, and snakes. (Como Zoo and Conservatory, 2003; Nowak, 1999)

Ecosystem Roles

As a prey species, it is likely that these small primates have some impact on predator populations. In addition, because they are largely frugivorous, they probably play some role in seed dispersal. (Nowak, 1999)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Debrazza's monkeys are hunted for their flesh in Zaire and Cameroon. They have also been widely collected for zoos, mainly from areas of Uganda and Kenya. From 1968 to 1973, 152 Debrazza's monkeys were imported into the United States and from 1965 to 1975, 373 were imported into the British Isles.

Economic Importance for Humans: Negative

There are no negative effects of Debrazza's monkeys on human economies.

Conservation Status

Debrazza's monkeys are neither endangered nor threatened. However, in 1975, Ethiopia started protecting them from being hunted and trapped. Threats to these monkeys include the pet trade, habitat destruction from deforestation, range fragmentation from increasing human populations, and cultivation, mainly of coffee plantations in Ethiopia. These monkeys can also be found protected on the Dja Reserve in Cameroon. (Oregon Zoo, 2005; Wolfheim, 1983)

Other Comments

Sometimes lone males are found outside the unimale social systems that the monkeys establish. Researchers believe the males disperse to create new troops. Research is now being done to see if females leave as well, to create new troops. (Riverbanks 2001)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Joshua Stein (author), Fresno City College, Rodney Olsen (editor), Fresno City College.

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.

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.

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.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

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.

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

Como Zoo and Conservatory, 2003. "DeBrazza's Monkey" (On-line). Como Zoo and Conservatory. Accessed May 28, 2005 at http://www.comozooconservatory.org/zoo/debrazza.htm.

Napier, J., P. Napier. 1970. Old World Monkeys: Evolution, Systematics, and Behavior. New York: Academic Press.

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

Oregon Zoo, 2005. "Debrazza's Monkey" (On-line). Oregon Zoo Animals. Accessed May 28, 2005 at http://www.oregonzoo.org/Cards/Savanna/monkey.debrazzas.htm.

Proutkina, M. March 26, 2001. Personal Communication. curator line (619)231-1515 between 2-3pm: San Diego Zoo Mammal Curator.

Wolfheim, J. 1983. Primates of the World: Distribution, Abundance, and Conservation. Seattle: University of Washington Press.