Wolf's Monkey (Cercopithecus wolfi)


MORPHOLOGY:
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:
  • Cercopithecus wolfi wolfi: This subspecies has a median dorsal chestnut-colored patch (Groves, 2001). The arms are black and the legs are red (Groves, 2001). The ventral side is yellow, occasionally with an orange stripe down the flanks (Groves, 2001). The cheek whiskers are yellow, speckled with black, and the ear tufts are red (Groves, 2001).
  • Cercopithecus wolfi pyrogaster: This subspecies is similar to Cercopithecus wolfi wolfi, but the arms are speckled with yellowish-white, the ventral side is red, and cheek whiskers are buffy, speckled with black (Groves, 2001).
  • Cercopithecus wolfi elegans: On the dorsal side, the color becomes browner towards the rump (Groves, 2001). The forearms are black, the upper arms having a pale speckling (Groves, 2001). The legs of this subspecies are light gray (Groves, 2001). The ventral side is white (Groves, 2001). The cheek whiskers are white, with dark speckling that increases posteriorly (Groves, 2001). The ear tufts are white (Groves, 2001).
Wolf's Monkey


RANGE:
Wolf's monkey is found in areas south of the Zaire River in the Democratic Republic of the Congo. This species is also found in Uganda. This species lives in young secondary forests (Mate et al., 1995). McGraw (1994) most often encountered this species in terra firma forests. This species also occurs in slope and swamp forests (McGraw, 1994).

This species has three subspecies that have differing ranges:

ECOLOGY:
Wolf's monkey is a frugivorous species that will also forage for insects. When foraging for insects, groups will split into two or more subgroups (Mulavwa, 1991). Feeding on nectar, such as from Daniellia pynaertii, has also been observed by Wolf's monkey (Maisels et al., 1993). Gautier-Hion et al. (1993) found that at Salonga this species consumed 30% leaves, 27% seeds, 32% fruit, and 11% flowers. This is a diurnal species. Moving and insect foraging primarily occur during the morning, while resting is found to occur primarily at midday (Mulavwa, 1991). Groups were found to spend 37 % of their time in the forest strata between 20-15 meters and 31% of their time between 25-20 meters (Mate et al., 1995). Mate et al. (1995) found that the mean group size for this species is 12 individuals. McGraw (1994) found that the average group size was 10.1 individuals. The crowned hawk eagle, Stephanoaetus coronatus is a predator of this species (Maisels et al., 1993; McGraw, 1994). When one group member was attacked by an eagle, the rest of the group fled to the ground along the forest floor (Maisels et al., 1993).

Wolf's Monkey-infant LOCOMOTION:
Wolf's monkey moves through the forest quadrupedally (Fleagle, 1988).

SOCIAL BEHAVIOR:
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).


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

sneeze call: This is used by Wolf's monkey as an alarm call; it resembles a sneeze.

contact call: These calls are emitted in response to the same calls, and group members on the periphery will respond quickly and frequently (Mulavwa, 1991). This call is found to be less frequently emitted at midday when fruit is abundant from July to September because when fruit is not available groups will move more often at midday (Mulavwa, 1991). This call is uttered more frequently when moving and foraging for insects (Mulavwa, 1991, 1990). This call is emitted so that an individual can know the position of the other group members (Mulavwa, 1991).

OLFACTORY COMMUNICATION:

VISUAL COMMUNICATION:
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).
Wolf's Monkey


TACTILE COMMUNICATION:
social grooming: This is when one individual will groom another, removing dead skin and parasites.

REPRODUCTION:
Wolf's monkey gives birth to a single offspring. Females are the ones who solicit copulation from the male (Estes, 1991). The birth season for this species is from about June to December (Gevaerts, 1992).

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:
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.
Wolf's Monkey


Mate, C., Colell, M., and Escobar, M. 1995. Preliminary observations on the ecology of forest cercopithecidae in the Lokofe-Ikomaloki Region (Ikela, Zaire). Folia Primatologica. Vol. 64, 196-200.

McGraw, S. 1994. Census, habitat preference, and polyspecific associations of six monkeys in the Lomako Forest, Zaire. American Journal of Primatology. Vol. 34, 295-307.

Mulavwa, M.H. 1990. Notes on the cohesion call of mona monkeys (Cercopithecus wolfi) in the Mabali Forest: Frequency of emission and daily activities. XIII Congress of the International Primatological Society. Nagoya and Kyoto, Japan, 20.

Mulavwa, M. 1991. Notes on the contact call of mona monkeys (Cercopithecus wolfi) in the Mabali Forest: Frequency of emission and daily activities. in Primatology Today. eds. A. Ehara, T. Kimura, O. Takenaka, and M. Iwamoto. Elsevier Science Publishers B.V.: Amsterdam.

Rowe, N. 1996. The Pictorial Guide to the Living Primates. Pogonias Press: East Hampton, New York.

Van Krunkelsven, E., Bila-Isia, I., and Draulans, D. 2000. A survey of bonobos and other large mammals in the Salonga National Park, Democratic Republic of Congo. Oryx. Vol. 34(3), 180-187.

Last Updated: June 8, 2007.
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