DeBrazza’s Monkey (Cercopithecus neglectus)

MORPHOLOGY: This species has cheek pouches to carry food in while it forages. The average body mass for an adult male DeBrazza’s monkey is around 7 kilograms, and for the female it is around 4 kilograms; this is a sexually dimorphic species. This species has the most robust feet of all of the guenons.

RANGE:
DeBrazza’s monkey is found in the countries of Angola, Burundi, Cameroon, Central African Republic, Equatorial Guinea, Ethiopia, Gabon, Rwanda, Uganda, and Zaire. This species is found inforest environs that are located near water and also in areas of dense vegetation.

ECOLOGY: DeBrazza’s monkey is primarily a frugivorous species, but seeds are also important part of the diet. This species will also eat leaves, flowers, and mushrooms. This species is diurnal and is both arboreal and terrestrial. Group sizes range from 4 to 35 individuals.

LOCOMOTION:
The DeBrazza’s monkey moves through the forest quadrupedally (Fleagle, 1988).

SOCIAL BEHAVIOR: The DeBrazza’s monkey has a unimale social system with a polygynous mating system. In some populations, this species tends to be more monogamous (Cords, 1987). Occasionally males try to over-take the resident male, but this does not always lead to a success. Males disperse from their natal groups.

VOCAL COMMUNICATION:
boom calls: These calls are performed by male DeBrazza’s monkeys (Estes, 1991). This call is low in frequency and is a short tonal call (Estes, 1991). The resonance is enhanced by air sacs to carry the distance further (Gautier and Gautier-Hion, 1977). This is used to communicate territoriality (Estes, 1991).

isolation calls: These are generally given by infant or juvenile DeBrazza’s monkeys, but sometimes they are emitted by adults (Estes, 1991). This call resembles a nasal grunt (Estes, 1991). This call is given when the individuals becomes separated from the troop. (Estes, 1991).

OLFACTORY COMMUNICATION:

VISUAL COMMUNICATION:
staring: This display by DeBrazza’s monkey is used as a threat display (Estes, 1991). The eyes are fixed on the stimulus and the eyebrows are raised and the scalp is retracted, the facial skin is also stretched by moving the ears back (Estes, 1991). Underneath the eye lids the color is different which contrasts sharply with the surrounding facial color (Estes, 1991)

staring with open mouth: This is the stare accompanied by the mouth being open but the teeth are covered (Estes, 1991). This is a threat expression and often occurs with head-bobbing (Estes, 1991).

head-bobbing: This is used as a threat display by the DeBrazza’s monkey and head bobs up and down (Estes, 1991). This often occurs with staring with open mouth (Estes, 1991).

fear grimace: The lips are retracted so that the teeth are shown; the teeth are clenched together (Estes, 1991). This display functions as an appeasement signal to reduce aggression in aggressive encounters (Estes, 1991).

yawning: This is where the mouth is opened to reveal the canines, and is performed by the adult male (Estes, 1991). This is used as an expression of tension or as a threat display (Estes, 1991).

head-shaking: This display indicates a sociable tendency, given during conflict situations (Estes, 1991). The head is rotated back and forth from side-to-side (Estes, 1991).

TACTILE COMMUNICATION: REPRODUCTION: DeBrazza’s monkey gives birth to a single offspring. Females are the ones who solicit copulations from the male (Estes, 1991). presenting: This behavior is preformed by the female to elicit copulation from the male; this pattern tells the male that she is ready for copulation (Estes, 1991). pouting: Females do this during copulation while looking over their shoulder at the male (Estes, 1991). The lower lip is extruded forward while the lips remain closed (Estes, 1991).

REFERENCES:
Burton, Frances. 1995. The Multimedia Guide to the Non-human Primates. Prentice-Hall Canada Inc.

Cords, M. 1987. Forest Guenons and Patas Monkeys: Male-Male Competition in One-male Groups. In Primate Societies, eds. B.B. Smuts, D.L. Cheney, R.M. Seyfarth, R.W. Wrangham, and T.T. Struhsaker. University of Chicago Press.

Estes, R.D. 1991. The Behavior Guide to African Mammals. University of California Press.

Fleagle, John G. 1988. Primate Adaptation and Evolution. Academic Press.

Last Updated: Ocotber 6, 2003.
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