Blue Monkey (Cercopithecus mitis)

MORPHOLOGY:
This species has cheek pouches to carry food in while it forages. The average body mass for an adult male blue monkey is around 6.9 kilograms, and for the female it is around 4.2 kilograms. Pelage (hair) color can be blue, reddish-brown, or grayish-brown.

RANGE:
The blue monkey is found in the countries of Angola, Burundi, Congo, Ethiopia, Kenya, Malawi, Mozambique, Rwanda, Somalia, South Africa, Sudan, Tanzania, Uganda, Zaire, Zambia, and Zimbabwe. This species is found in a variety of habitats, but it is always found not far from a water source.

ECOLOGY:
The blue monkey is a frugivorous species, and will also eat seeds, arthropods, and leaves (Cords, 1987). Group sizes for this species range from 10 to 40 individuals. This species is highly arboreal and is also diurnal. The troop disperses widely when foraging for food (Rudran, 1978).

LOCOMOTION:
The blue monkey moves through the forest quadrupedally (Fleagle, 1988).

SOCIAL BEHAVIOR:
The blue monkey has a unimale social system with a polygynous mating system (Estes, 1991), although promiscuous mating has been known to occur (Tsingalia and Rowell, 1984). The resident male receives all of the copulations from the troop females (Estes, 1991). He also guards the troop against other conspecific troops and males (Estes, 1991). Females also join in confrontations with other conspecific troops (Estes, 1991). Take-overs of troops do occur with the resident male sometimes being ousted from the troop (Estes, 1991). Blue monkeys form mixed-species associations with Cercopithecus ascanius, this probably for protection against predators (Estes, 1991). They do not compete for resources because they forage in different locations and use different methods in the forest (Richard, 1985). Butynski (1982) reported that infanticide did occur in this species. Allomaternal care does occur amongst the female troop members (Bourliere et al., 1970; Struhsaker and Leland, 1979).

VOCAL COMMUNICATION:
boom calls: These calls are performed by male blue 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).

pyow calls: These calls are performed by male blue monkeys (Estes, 1991). This call is loud and travels for hundreds of meters and is emitted in a slow series at a regular interval (Estes, 1991). These calls are individual specific and are used to rally other troop members and to keep other adult males away (Estes, 1991).

ka-train calls: These calls are performed by male blue monkeys (Estes, 1991). This call starts out as a burst of sound followed by bursts of pulses, that are either given singularly or in a series (Estes, 1991). These function to warn when a flying predator is near and also used during aggressive bouts (Estes, 1991).

phrased grunt: This call serves to maintain group cohesion and is emitted by females of the troop (Estes, 1991). This call is soft and rhythmical (Estes, 1991).

chirps: These noises are uttered by females and subadults of the troop and is used to bring the troop to alterness, 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).

trills: This call is given by subadults when approached by adults, thus it may communicate submissiveness (Estes, 1991). These noises are soft, descending in pitch, and tend to oscillate (Estes, 1991).

OLFACTORY COMMUNICATION:

VISUAL COMMUNICATION:
staring: This display by the blue 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 blue 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 blue 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:
Bourliere, F., Hunkeler, C., and Bertrand, M. 1970. Ecology and Behaviour of Lowe’s Guenon (Cercopithecus campbelli lowei) in the Ivory Coast. In Old World Monkeys, eds. J.R. Napier and P.H. Napier. Academic Press.

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

Butynski, T.M. 1982. Harem-male Replacement and Infanticide in the Blue Monkey (Cercopithecus mitis stuhlmanni) in the Kibale Forest, Uganda. American Journal of Primatology, Vol. 3, 1-22.

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.

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

Richard, A.F. 1985 Sympatry, Competition, and the Niche. In Primates in Nature, ed. A.F. Richard. W. H. Freeman and Company.

Rudran, R. 1978. Socioecology of the Blue Monkeys (Cercopithecus mitis stuhlmanni) of the Kibale Forest, Uganda. Smiths. Contrib. Zool., Vol. 249, 88pp.

Struhsaker, T.T. and Leland, L. 1979. Socioecology of Five Sympatric Monkey Species in the Kibale Forest, Uganda. In Advances in the Study of Behavior, Vol. 9 eds. J.S. Rosenblatt, R.A. Hinde, C. Beer, and M.C. Busnel. Academic Press.

Last Updated: October 6, 2003.
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