Cercopithecus wolfi is most commonly found in the Democratic Republic of Congo and areas in Uganda. There are three subspecies of Wolf’s monkey: Cercopithecus wolfi wolfi occurs between the Congo and Sankuru Rivers, Cercopithecus wolfi pyrogaster is found between the Kwango and Kasai-Lulua Rivers, and Cercopithecus wolfi elegans is found between the Lomami and Lualaba Rivers.

Biogeographic Regions: ethiopian (Native )

Wolf's monkeys have dark grey fur dorsally with a reddish patch in the center of the back. The ventral fur is usually white or pale yellow. The forelimbs are dark grey to black while the hindlimbs are a light reddish-brown color. The distal half of the tail is black while the proximal half is a grayish coloration. The face is characterized by a black patch extending from ear to ear, from below the eyes to the top of the head. Within this black area is a patch of white fur that grows from the brow. The cheeks and chin are the same whitish-yellow as the ventral fur and the ear tufts are often white or slightly reddish. The scrotum is blue, which may be important in mate selection. Blue scrotal color is common in many Cercopithecus species and related genera. Wolf's monkeys have ischial callosities (callus-like areas of skin on the buttocks). This provides a degree of comfort while sitting on branches and night resting. These callosities are typical of the family Cercopithecidae.

Being an arboreal quadruped, Wolf's monkeys have forelimbs and hindlimbs that are fairly equal in length giving it an intermembral index number close to 100. The head and body length of males varies from 445 to 511 mm with an average of 485 mm. The length of the tail in males ranges from 695 to 822 mm with an average of 779 mm. There has not been enough data collected from females to adaquetely determine these measurements. Cercopithecus wolfi is a sexually dimorphic species. The weight of males ranges from 3.8 to 4.2 kg, females are considerably smaller, ranging from 2.4 to 3.1 kg. Males also have larger canine teeth than females.

Range mass: 2.4 to 4.2 kg.

Range length: 445 to 511 mm.

Average length: 485 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

• Terrestrial

Cercopithecus wolfi occupies primary and secondary lowland rainforest habitats. Wolf's monkeys are commonly found in swamp forests and secondary forests along riverbanks. They spend a majority of their time between 15 and 25 meters high in the canopy where they forage and sleep.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: rainforest

Other Habitat Features: riparian

Wolf's monkeys are frugivorous, but they supplement their diet heavily with leaves, seeds, and flowers. At Salonga National Park in the Democratic Republic of Congo, Wolf's monkeys have been recorded consuming 32% fruit (4% fleshy and 27% arils), 27% seeds, 29% leaves, and 11% flowers. Though not a primary means of sustenance, Wolf’s monkeys will occasionally feed on nectars and insects if they are readily available. The principal feeding time for this species is during the early morning and early afternoon.

Animal Foods: insects

Plant Foods: leaves; seeds, grains, and nuts; fruit; nectar; flowers

Primary Diet: herbivore (Frugivore )

Wolf's monkeys are probably important in seed dispersal of food trees and they may contribute to pollination when they drink nectar.

Ecosystem Impact: disperses seeds

Since this species is arboreal, its main predators are avian, primarily crowned hawk eagles (Stephanoaetus coronatus). When these birds are spotted by Wolf's monkeys, they will sound an alarm call and retreat to the ground. Though less common, leopards also pose a threat to this species. More recently, humans have become a major predator of this species for the bush meat market. In addition, their primary habitat is being destroyed at an extremely rapid pace for lumber.

Known Predators:

• crowned hawk eagles (Stephanoaetus coronatus)
• leopards (Panthera pardus)

Vocalizations of Wolf’s monkeys includes 2 contact calls, 2 travel calls, and 3 alarm calls. The most common contact call is used while foraging. These monkeys let out an occasional grunting sound to maintain vocal contact and know the positions of other members of the group. These calls are made more often when foraging in large groups or in areas of low visibility, such as the upper areas of the canopy. Vocal communication is also more common while hunting for insects than foraging for fruits and leaves. To communicate territoriality, males let out a boom call, which is a low, short tone that can be carried long distances due to resonating air sacs. A common alarm call is the sneeze call. It is a short call resembling a the sound of a sneeze.

This species also uses visual communication to convey threats and aggression. Males fix their eyes on the target, move back their ears to stretch out the facial skin, and retract their scalp. This is called staring. Along with staring, they will sometimes open their mouths, but keep the teeth hidden. To present an even greater threat, they will stare with their mouth open, but begin bobbing their head. A fear grimace is used as an appeasement signal to reduce aggression in aggressive encounters. This is accomplished by retracting the lips to show the teeth, but keeping the teeth closed together. Males also perform a visual cue that resembles yawning. The mouth is opened and the canines are revealed to convey tension or aggression.

Like other primates, Wolf's monkeys also extensively use grooming for tactile social communication. The use of chemical cues, such as pheromones, is likely, but undocumented.

Communication Channels: visual ; tactile ; acoustic ; chemical

Perception Channels: visual ; acoustic

The average lifespan is reported to be 20 to 26 years.

Typical lifespan

Status: wild: 20 to 26 years.

The mating system is a single-male, multi-female polygynous system. There is usually one dominant male and sometimes several less dominant males that mate with a larger number of females. In groups with many females and a single male, males from nearby bachelor groups will often come into the group to mate with females and then retreat to their bachelor group. Copulation is usually initiated by females. They will often present their genitals to a male as a way of enticing him. Though it seems to serve no reproductive function, females will often engage in “pouting” during copulation. This means that the female will look back over her shoulder and pout out her bottom lip at the male.

Mating System: polygynous

Wolf's monkeys give birth to one offspring at a time, though twins occur rarely. Most births occur from June to December when there is the greatest abundance of food. Gestation length is from 160 to 170 days and the young are nursed for 3 months after birth. Females produce their first young at 4 to 5 years old.

Breeding interval: Interbirth interval in Wolf's monkeys is not documented. Other Cercopithecus species generally give birth every year, although interbirth intervals can be as high as 5 years in some populations.

Breeding season: There is no fixed breeding season, although most births occur from June to December.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Range gestation period: 160 to 170 days.

Average weaning age: 180 days.

Average time to independence: 180 days.

Average age at sexual or reproductive maturity (female): 4.5 years.

Average age at sexual or reproductive maturity (male): 4.5 years.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Not much information is known about the parental investment of Wolf's monkeys, though it has been observed that infants will ride on the backs of their mothers for the first few months after birth. Female young stay in their natal group, male young disperse from their natal group when they become independent.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); post-independence association with parents

Cercopithecus wolfi has not been evaluated by the IUCN. As a primate, C. wolfi is on appendix II in CITES.

US Federal List: no special status

CITES: appendix ii

IUCN Red List of Threatened Species: least concern

Wolf's monkeys occasionally raid local agricultural crops and have a potential for carrying diseases that can be contagious to humans.

Negative Impacts: injures humans (carries human disease); crop pest

Wolf's monkeys are one of the species hunted in the bushmeat market. Their meat provides food to local inhabitants and a product to trade for other goods. They are also likely to play a role in the regeneration of healthy forests through seed dispersal.

Positive Impacts: food