This species has cheek pouches to carry food in while it forages. The dental formula of Wolf's monkey is 2:1:2:3 on both the upper and lower jaws (Ankel-Simons, 2000). Adult males have an average body mass of around 4.5 kilograms and adult females have an average body mass of around 2.5 kilograms (Mate et al., 1995). The dorsal pelage of this species is dark gray, with having a reddish saddle on the back (Rowe, 1996). The ventral side is yellow or white (Rowe, 1996). The arms are black and the legs are brownish-red in coloration (Rowe, 1996). The distal-half of the tail is black (Rowe, 1996). On the face there is a broad band of black from the eyes to the ears (Rowe, 1996). The ear tufts of this species are red or white (Rowe, 1996). The male's scrotum is blue in color (Groves, 2001).
This species has three subspecies each having their own pelage coloration:
Wolf’s monkey moves through the forest quadrupedally (Fleagle, 1988).
Wolf’s 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. Wolf's monkey will form mixed-species groups with red-tailed monkeys, Cercopithecus ascanius, and with black mangabeys, Cercocebus atterimus (Ihobe, 1997; Van Krunkelsven et al., 2000; Mate et al., 1995; McGraw, 1994). This species will also sometimes form mixed-species groups with the Angolan Black-and-white colobus monkey, Colobus angolensis, and Allen's swamp monkey, Allenopithecus nigroviridis (McGraw, 1994). McGraw (1994) found that Wolf's monkey when a mixed group will move and forage at a mean height of 17.12 meters, which differs from the red-tailed monkey (12 meters) and the black mangabey (21.5 meters), so the species are not competing for similar food when they travel. Mixed-species groups may form for predator detection (Mate et al., 1995; McGraw, 1994). This species will feed in the same or neighboring tree as a feeding or resting bonobo, Pan paniscus, with no aggression coming from the bonobo (Ihobe, 1997).
staring: This display by Wolf’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 Wolf’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).
Ankel-Simons, F. 2000. Primate Anatomy. Academic Press: San Diego.
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: New York.
Gautier, J.P. and Gautier-Hion, A. 1977. Communication in Old World Monkeys. In Sebeok 1977.
Gautier-Hion, A., Gautier, J.P., and Maisels, F. 1993. Seed dispersal versus seed predation: An inter-site comparison of two related African monkeys. Vegetatio. Vol. 107/108, 237-244.
Gevaerts, H. 1992. Birth seasons of Cercopithecus, Cercocebus and Colobus in Zaire. Folia Primatologica. Vol. 59, 105-113.
Groves, C.P. 2001. Primate Taxonomy. Smithsonian Institute Press: Washington, D.C.
Ihobe, H. 1997. Non-antagonistic relations between wild bonobos and two species of guenons. Primates. Vol. 38(4), 351-357.