Animal Diversity Web

Geographic Range

Campbell's monkeys (Cercopithecus campbelli) are native to the Ethiopian region, in the coastal area of western Africa. Their known range extends as far northwest as Banjul, the Gambia, and as far southwest as Cotê D'Ivoire. Campbell's monkeys occupy the countries of Liberia, Guinea, Sierra Leone, Guinea Bissau (including the island of Caravela), and Senegal. (Matsuda Goodwin, et al., 2020)

• Biogeographic Regions
• ethiopian
  • native

Habitat

Campbell's monkeys live in terrestrial environments, such as lowlands and gallery forests, which are forested riparian corridors in an otherwise open landscape (e.g., savannas, grasslands). Campbell's monkeys also inhabit shrublands, mangroves, woodlands, and savannas. As arboreal primates, Campbell's monkeys live in the understory and shrub layers of forests. Campbell's monkeys live at elevations from 0 to 600m above sea level. (Matsuda Goodwin, et al., 2020; Zuberbuhler, 2001)

• Habitat Regions
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest

• Wetlands
• marsh

• Other Habitat Features
• riparian

• Range elevation

  0 to 600 m

  0.00 to 1968.50 ft

Physical Description

Campbell's monkeys have brownish grey dorsal fur and tawny-brown ventral fur. They have white eyebrows, and their faces are dark grey to bluish-black from their foreheads to just below their eyes. They have round, furry cheeks and ears that are yellowish-white. Campbell's monkeys have pink noses and white whiskers. They have long, thin tails that are dark grey or black.

Female Campbell's monkeys are smaller than males on average. Females range from 360 to 430 mm in length and 2.0 to 4.5 kg in weight. The tails of females are 580 to 680 mm long. Males range from 420 to 550 mm in length and 3.2 to 5.5 kg in weight. Their tails are 490 to 850 mm long.

Apart from differences in size, male and female Campbell's monkeys look alike. Juveniles tend to have pinker faces with pelage that is more consistently grey. (Kingdon, 2013)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  2.0 to 5.5 kg

  4.41 to 12.11 lb

• Range length

  360 to 550 mm

  14.17 to 21.65 in

Reproduction

Campbell's monkeys are polygynous. They live in troops with one dominant male that mates with multiple females. Male Campbell's monkeys attract females by emitting low-pitched barks and females respond with high-pitched whistles and calls. This acoustic communication helps Campbell's monkeys locate each other in forested environments. Once a sexually active male and female meet, the male places its hand on the rump of the female, and the female decides whether to permit copulation. Mating behaviors do not affect social structures, as the males protect all the females in the troop equally. Campbell's monkeys mate year-round, but the highest rates of pregnancy occur in June and July. (Kingdon, 2013)

• Mating System
• polygynous

Campbell's monkeys breed year-round, but mating rates are highest in June and July. Breeding intervals of females have not been reported. With a 25-week gestation period, most juveniles are born in December or January. Females give birth to a single offspring. Twins have never been reported in Campbell's monkeys. Birth weights for Campbell's monkeys can range between 0.324 and 0.540 kg. For all members of the genus Cercopithecus, birth weights of juveniles are between 9% and 15% of the body weight of mothers.

Juvenile Campbell's monkeys are usually weaned after one year. Females reach sexual maturity after 3 years, but age of maturity is unreported for males. If an incoming male outcompetes and replaces a dominant male, it also kills any unweaned juveniles to minimize male-to-male competition. (Hiraiwa-Hasegawa, 1988; Kingdon, 2013; Nakamichi and Yamada, 2009)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• viviparous

• Breeding season

  June - July but can be year-round

• Average number of offspring

  1

• Average gestation period

  25 weeks

• Average weaning age

  12 months

• Average age at sexual or reproductive maturity (female)

  3 years

Female Campbell's monkeys provide all direct parental care for juveniles, nursing them and helping them gather food for 1 year. Females also teach their young how to use their tails and interpret social calls. Juveniles are weaned for a year and become fully independent after 3 years. They usually leave the troop once they become independent. Dominant males protect their young indirectly until independence by giving off warning calls for predators and calls for food nearby. (Lemasson, et al., 2003; Smuts and Gubernick, 2017)

• Parental Investment
• female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • male
    • female
• extended period of juvenile learning

Lifespan/Longevity

The average lifespan of Campbell's monkeys in captivity or in the wild is not reported. However, Lowe's monkeys (Cercopithecus lowei) are closely related and have a reported captive lifespan of 30 years. The black market trade of bushmeat typically limits the lifespan of adults, because adults are sold for higher prices. The lifespans of juveniles are predominantly limited by predation. (Matsuda Goodwin, et al., 2020; Weigl, 2005)

Behavior

Campbell's monkeys are arboreal and social, living in large groups that can range from 9 to 14 members. There is typically one adult male in the group and the rest are females or juveniles. There are reports of groups that have multiple males or are only males, but these instances are rare. During the day, Campbell's monkeys spend their time grooming each other, vocalizing about predators, foraging, and play fighting with other species. They groom other Campbell's monkeys in their troop, but also western red colobuses (Piliocolobus badius), and olive colobuses (Procolobus verus). It is estimated that Campbell's monkeys spend 7% of their time socializing with conspecifics and other species. They vocalize to their fellow troop members when potential predators are near. They spend 46% of their time running and jumping, and 28% of their time foraging for food and eating.

Campbell's monkeys are not known to migrate.

Campbell's monkeys communicate with other species that share their habitat, including Diana monkeys (Cercopithecus diana). Campbell's monkeys relay messages about predators to Diana monkeys to help protect their groups. When they are with Diana monkeys, they will move out of the lower forest strata and into the middle strata.

Campbell's monkeys can use the more exposed parts of the forest. They distance themselves from other members of their troop and vocalize to stay in touch. The presence of Campbell's monkeys cause Diana monkeys to be less vigilant about predators. Diana monkeys also spend more time foraging when Campbell's monkeys are present. The two species have a mutually beneficial relationship with each other. (Matsuda Goodwin, et al., 2020; Wolters and Zuberbuhler, 2003; Zausa, et al., 2018)

• Key Behaviors
• arboreal
• diurnal
• motile
• sedentary
• territorial
• social

Home Range

One troop of Campbell's monkeys has an estimated home range of 40 ha to 67 ha. There are no known reports of territory size, but Campbell's monkeys often get into territorial disputes with Diana monkeys (Cercopithecus diana). Other territorial disputes often involve other species of the genus Cercopithicus. (Kingdon, 2013; Matsuda Goodwin, et al., 2020)

Communication and Perception

Campbell's monkeys use different calls to communicate with the other members of their troop. Communication often involves the presence of predators, food, or other important environmental cues. The calls of individual Campbell's monkeys differ in tone, with some being able to produce sounds others can not. Calls range in both volume and acoustic characteristics. Adult males typically make warning calls about predators. They are able to understand calls given by the members of their group. Campbell's monkeys have a high level of visual and acoustic perception.

Campbell's monkeys are able to respond to the calls of conspecifics. Upon hearing a predator call, adult males run towards the call, while the females and juveniles do not approach. Campbell's monkeys groom each other. Females perform most if not all of the grooming for juveniles. Mating occurs through tactile and pheromone exchanges in which a male places its hand on the rump of a female, and that female decides whether or not to mate. Female Campbell's monkeys release pheromones to let males know that they are ready to mate. (Curtis, et al., 1971; Lemasson and Hausberger, 2004; Nowak, 1999; Zuberbuhler, 2001)

• Communication Channels
• visual
• tactile
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Campbell's monkeys primarily consume fruits, leaves, seeds and grains. On occasion, they eat young birds, bird eggs, small reptiles, and insects. In the Tai Forest, one of primary locations for Campbell's monkeys, it was reported that fruits composed 46% of their diet. Adult males eat more fruit than females, and females eat more foliage and animal matter. Juveniles eat more animal matter and fruit and very little foliage.

Campbell's monkeys have cheek pockets in which they store food. They carry food in pockets in their cheeks to a location they deem safe from predators. Campbell's monkeys have distended cheek pockets, but the level of distension in juveniles is smaller than in adults. (Buzzard, 2006; Nowak, 1999)

• Primary Diet
• herbivore
  • folivore
  • frugivore
  • granivore

• Animal Foods
• birds
• reptiles
• eggs
• insects

• Plant Foods
• leaves
• seeds, grains, and nuts
• fruit

Predation

Campbell's monkeys have predator-specific calls that they use to warn nearby troops that predators are around. Adult males call, signaling for females and juveniles to hide while other adult males in the area run towards the threat. Calls differ among predators by specific variances in tone and pitch.

Known predators of Campbell's monkeys include humans (Homo sapiens), leopards (Panthera pardus), western chimpanzees (Pan troglodytes), and crowned hawk-eagles (Stephanoaetus coronatus). Humans pose the largest threat to Campbell's monkeys, due largely to the trade of bush meat in western Africa. (Zuberbuhler, 2001)

• Known Predators

  • Humans (Homo sapiens)
  • Leopards (Panthera pardus)
  • Western chimpanzees (Pan troglodytes)
  • Crowned hawk-eagles (Stephanoaetus coronatus)

Ecosystem Roles

Campbell's monkeys eat seeds, fruits, leaves, and grains, as well as bird and reptile eggs and insects. They are eaten by humans (Homo sapiens), leopards (Panthera pardus), western chimpanzees (Pan troglodytes), and crowned hawk-eagles (Stephanoaetus coronatus).

Campbell's monkeys serve as hosts for the following protozoan parasites: heterkonts (Blastocystis), ciliates (Balantidium coli), anaerobic protozoans (Giardia and Chilomastix mesnili), and amoebozoans (Entamoeba coli, Entamoeba histolytica, Entamoeba dispar, Entamoeba hartmanni, Endolimax nana, Iodamoeba butschlii). Roundworm parasites include whipworms (Trichuris), false hookworms (Ternidens), and unknown roundworms in the family Capillariidae. Additional nematodes include Strongyloides stercoralis and those in the genera Oesophagostomum, Ancylostoma, Subulura, and Trichostrongylus. (Matsuda Goodwin, et al., 2020; Roland, et al., 2015)

Economic Importance for Humans: Positive

Campbell's monkeys benefit humans by providing a source of food. In coastal Africa, they are part of the bushmeat trade. They are hunted throughout their geographic range. A study in 2003 found that approximately 8,953 kg of bushmeat was consumed around the Tai National Park, an area with a large population of Campbell's monkeys. Bushmeat from Campbell's monkeys ranges in price from 5,000 CFA ($8.80 USD) for large males in Cote d'Ivoire to 2,000 CFA ($3.60 USD) for several pieces of bushmeat in Bissau. Campbell's monkeys weighing less than 3.6kg were sold for 3,000 CFA ($5.30 USD) in southwest Cote d'Ivoire. (Matsuda Goodwin, et al., 2020; Refisch and Kone, 2005)

• Positive Impacts
• food

Economic Importance for Humans: Negative

Campbell's monkeys are a zoonotic vector of yellow fever, which is known to infect humans. Furthermore, human contact with Campbell's monkeys is likely. Campbell's monkeys live in the lower strata of the forest and sometimes spend time on the forest floor or close to villages. (Kingdon, 2013)

• Negative Impacts
• injures humans
  • causes disease in humans
  • carries human disease

Conservation Status

Campbell's monkeys are listed as "Near Threatened" on the IUCN Red List. They are included in the CITES Appendix II, where trade regulations have been listed, such as an international trade export permit. Campbell's monkeys are also listed in Class B of the African Convention of the Conservation of Nature and Natural Resources. They have no special status on the United States Endangered Species Act list or the State of Michigan list.

The bushmeat trade in Africa plays a large role in the status of Campbell's monkeys. Due to domesticated meat being a rarity, many people rely on bushmeat as their major source of protein. In 2020, Campbell's monkeys were "uplisted" from Least Concern to Near Threatened on the IUCN Red List. Increasing pressure from hunters and the growing African population has caused Campbell's monkey populations to decline. They live in close proximity to villages, and as villages grow in size, the amount of suitable habitat for Campbell's monkeys shrinks. Within their geographic range, an estimated 30% of suitable habitats are lost or degraded. They are able to live in farm brush near human populations, but increasing pressure from bushmeat hunting puts them at greater risk in those areas. Despite declines in number by less than 30% over the past 36 years, the rate of decline is expected to rise rapidly with the decline in accessibility of larger primates in bushmeat trade, and as the human population increases. Campbell's monkeys also hybridize with mona monkeys (Cercopithecus mona).

There are many conservation efforts in place for all monkey species in Africa. Campbell's monkeys have populations located in many nationals parks such as Gola National Park, Loma National Park, Grebo National Park, and Sabo National Park. They are also present at an island in Liberia, named Tiwai, which is conserved for wildlife. In the Tai National Park, there is a side where poaching is overlooked and a side where poaching is not allowed. The population density of Campbell's monkeys is larger on the non-poaching side. Poaching is illegal, but many poachers are not honest about the location from which they obtained the meat, so it is very hard to track and enforce. There are also many anti-poaching efforts in Sabo National Park. (Kingdon, 2013; Matsuda Goodwin, et al., 2020; Refisch and Kone, 2005)

• IUCN Red List

  Near Threatened

• US Federal List

  No special status

• CITES

  Appendix II

• State of Michigan List

  No special status

Contributors

Kaitlynn Leinberger (author), Radford University, Sierra Felty (editor), Radford University, Bianca Plowman (editor), Radford University, Karen Powers (editor), Radford University, Victoria Raulerson (editor), Radford University, Christopher Wozniak (editor), Radford University, Genevieve Barnett (editor), Colorado State University.

References

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