Greater White-nosed Monkey (Cercopithecus nictitans)


MORPHOLOGY:
This species has cheek pouches to carry food in while it forages. The average body mass for an adult male greater white-nosed monkey is around 6.6 kilograms, and for the females it is around 4.2 kilograms. There is a white spot on the nasal area, thus the origin for the common name.

RANGE:
The greater white-nosed monkey is found in the countries of Cameroon, Central African Republic, Congo, Equatorial Guinea, Gabon, Ivory Coast, Liberia, Nigeria, Sierra Leone, and Zaire. This species is found in forest habitats that are seasonally flooded or near rivers and also the forests tend to be mature.

ECOLOGY:
The greater white-nosed monkey is a frugivorous species, but seeds also constitute a major part of the diet. This species also consumes leaves, arthropods, and gum. Group sizes range from 13 to 60 individuals. This species is arboreal and diurnal.

LOCOMOTION:
The greater white-nosed monkey moves through the forest quadrupedally (Fleagle, 1988).

SOCIAL BEHAVIOR:
The greater white-nosed monkey has a unimale social system with a polygynous mating system. Occasionally males try to over-take the resident male, but this does not always lead to a success. The males disperse from their natal groups in this species.

VOCAL COMMUNICATION:
boom calls: These calls are performed by male greater white-nosed 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).

chirps: These noises are uttered by females and subadults of the troop and is used to bring the troop to alertness, stimulate mobbing behavior, stimulate the leaving of open areas, and to elicit calling (Estes, 1991). These calls are birdlike in nature and tend to be short in duration (Estes, 1991).

isolation calls: These are given by group members separated from the troop (Estes, 1991). In the greater white-nosed monkey these calls tend to be noisy, and they are most often emitted by infants and juveniles (Estes, 1991).

OLFACTORY COMMUNICATION:
mutual genital sniffing: Two individuals sniffs each others anogenital region at the same time (Estes, 1991). Males perform this behavior upon each other (Estes, 1991).

muzzle sniff: This behavior is performed by juvenile male greater white-nosed monkeys (Gautier and Gautier-Hion, 1977). This is done by the juvenile male to an adult male when the adult is giving a loud call (Gautier and Gautier-Hion, 1977).

VISUAL COMMUNICATION:
staring: This display by the greater white-nosed 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 greater white-nosed 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).

TACTILE COMMUNICATION:

REPRODUCTION:
The greater white-nosed monkey gives birth to a single offspring. Females are the ones who solicit copulation from the male (Estes, 1991). During estrus the vulva of the female swells and pinkens (Gautier-Hion and Gautier, 1976).

presenting: This behavior is performed 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, F. 1995. The Multimedia Guide to the Non-human Primates. Prentice-Hall Canada Inc.

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

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

Gautier, J.P. and Gautier-Hion, A. 1977. Communication in Old World Monkeys. In Sebeok 1977.

Gautier-Hion, A. and Gautier, J.P. 1976. Croissance, Maturite Sexuelle et Sociale, Reproduction chez les Cercopithecines Forestiers Africains. Folia Primatologica Vol. 22, 134-177.

Last Updated: June 8, 2007.
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