By Joshua Stein
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)
These animals are found in the following types of habitat:
tropical 
; terrestrial .
Terrestrial Biomes:
forest ; rainforest .
Physical Description
(8.8 to 15.4 lbs)
(15.75 to 25 in)
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)
Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .
Sexual dimorphism: male larger.
Reproduction
The exact breeding interval is not known.
The known breeding season in the equatorial rain forest is from February to March.
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; Oregon Zoo, 2005)
Mating systems:
polygynous .
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)
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .
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 and March 26, 2001)
Home Range
Home range sizes are not reported.
Key behaviors:
arboreal ; diurnal ; motile ; sedentary ; territorial ; social ; dominance hierarchies .
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 and 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)
Primary Diet:
omnivore .
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)
Key ways these animals impact their ecosystem:
disperses seeds.
Economic Importance for Humans: Negative
There are no negative effects of Debrazza's monkeys on human economies.
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.
Conservation Status
IUCN Red List: [link]:
Lower Risk - Least Concern.
US Federal List: [link]:
No special status.
CITES: [link]:
Appendix II.
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)
For More Information
Find Cercopithecus neglectus information at
Contributors
Nancy Shefferly (editor), Animal Diversity Web Staff.
Joshua Stein (author), Fresno City College.
Rodney Olsen (editor), Fresno City College.
