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Cercopithecus dianaDiana monkey

By Karen Kennedy

Geographic Range

Cercopithecus diana is distributed from Sierra Leone to Ghana, in Western Africa.

Habitat

Diana monkeys dwell in upper levels of primeval forest trees. They sleep in trees in closed forest canopies, and never make nests.

Physical Description

Cercopithecus diana ranges from 40 to 55 cm in length, with a long tail 50 to 75 cm long. The coloration is extremely variable. These primates are generally black, with a white throat, ruff, pointed beard, and anterior side of arms. A white stripe runs down the thighs (Kingdon 1989). The posterior back and thighs are red-brown to orange (Grzimek 1990). Cercopithecus diana is catarrhine, with the nostrils close together and facing downward. The nail on each digit is flattened. The hallux and pollex are opposable. Prominant calluses, or ischial callosities, are present on the rump. The dental formula is 2/2, 1/1. 2/2, 3/3=32 (Vaughan 1986).

  • Range mass
    4 to 7 kg
    8.81 to 15.42 lb

Reproduction

Diana monkeys have a polygynous mating system. Courtship is short, since mates are usually familiar with each other. The female presents her rump prior to copulation in an appeasement gesture to signal readiness and vulnerability (Vaughan 1986).

Diana monkeys breed seasonally. They are polyestrus, with an approximately 31 day cycle. The gestation period lasts 5 months (Cockrum 1962). Females give birth to one or rarely two young at a time. The young are weaned at about six months and reach sexual maturity at about three years (Grzimek 1990).

  • Breeding interval
    Because these animals breed seasonally, and given the long period of infant dependence, it is likely that females are only bale to produce once per year.
  • Breeding season
    Copulations are probably times so that the young are born at the period of maximum food availability.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
    AnAge
  • Average gestation period
    5 months
  • Average weaning age
    6 months
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    1962 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    3 years

The young are relatively well developed at birth, with open eyes and the capability to grasp the mother and support their own weight (Macdonald 1984). Females nurse and care for their offspring for about six months. Daughters stay with their mothers as long as they live, whereas males leave the natal group near the time of adolescence (Macdonald 1984).

  • Parental Investment
  • precocial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female
  • post-independence association with parents
  • extended period of juvenile learning
  • maternal position in the dominance hierarchy affects status of young

Lifespan/Longevity

These animals are thought to reach a maximum age of about 20 years.

Behavior

Cercopithecus diana is arboreal and diurnal. Diana monkeys are social, living in groups of 15 to 30 individuals with a single adult male. These monkeys communicate with one another with calls and visual cues. The well developed facial muscles along with the coloration allow a wide range of facial expressions for communication. These monkeys may "grin" in appeasement to dominating individuals (Vaughan 1986). Their vocal communication includes general vocalizations, alarm and contact calls.

The young play constantly, learning to be agile and swift in the trees. ( http://www.uni.edu/museum/cercopan/guenons.html)

Home Range

The territory size is between 0.5 and 1 square km.

Communication and Perception

As in all primates, communication is likely to be varied and complex. Facial expression and body postures are some of the visual cues primates use to communicate mood and intent. Vocalizations are common in primates. Tactile communication is important in social bonding and maintenance of relationships. Grooming, mating, and caring for young are all very tactile.

Food Habits

Diana monkeys are omnivorous, eating fruits, flowers, young leaves, insects and invertebrates (Grzimck 1990, Macdonald 1984).

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • leaves
  • fruit
  • flowers

Predation

As is common in other forest monkeys, predators are likely to include leopards, snakes, and birds of prey.

Ecosystem Roles

As a prey species, these monkeys are likely to have an impact on predator populations. As fruit eaters, they are likely to help disperse seeds.

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Diana monkeys are used for food, pets, and in medical research (Macdonald 1984, Lawlor 1979).

Economic Importance for Humans: Negative

Diana monkeys can carry and spread diseases like yellow fever and tuberculosis (Macdonald 1984).

Conservation Status

The current status of C. diana is CITES-Appendix I; US ESA- Endangered, IUCN- vulnerable (Wilson and Reeder 1993). Diana monkeys are seriously threatened by hunting and by destruction of forests (Grzimck 1990). One subspecies, C. diana roloway, is recognized; it lives in the Ivory Coast and Ghana.

Other Comments

The life span of C. diana may exceed two decades.

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Karen Kennedy (author), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born

References

Cockrum, E. 1962. Introduction to Mammalogy. The Ronald Press Company, New York.

Grzimck's Encyclopedia of Mammals. Vol. 2. 1994. McGraw-Hill Publishing Company, New York.

Kingdon, J. 1989. Island Africa. Princeton University Press, Princeton.

Lawlor, T. 1979. Handbook to the Orders and Families of Living Mammals. Mad River Press, Eureka.

Macdonald, D. 1984 Encyclopedia of Mammals. Facts on File Publications, NY.

Vaughan, T. 1986. Mammalogy. Harcourt Brace Jovanovich, Orlando.

Wilson, D. and Reeder, D. 1993. Mammal Species of the World: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington.

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