Animal Diversity Web

Ge­o­graphic Range

Red­tail mon­keys (Cer­co­p­ithe­cus as­ca­nius) are found in Africa from the Cen­tral African Re­pub­lic east­wards through Kenya and south into An­gola and Zam­bia. Pop­u­la­tions are most dense in Uganda. (Smuts, et al., 1987)

• Biogeographic Regions
• ethiopian
  • native

Habi­tat

Red­tail mon­keys can live in a rather large va­ri­ety of habi­tats. They are mainly found in the mid­dle canopy of trop­i­cal rain for­est habi­tats. How­ever, they have also been ob­served in swamp forests, sec­ondary forests, river­ine gallery for­est, and other wood­lands (Smuts et al. 1987). (Smuts, et al., 1987)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• forest
• rainforest

Phys­i­cal De­scrip­tion

This rel­a­tively small pri­mate ex­hibits some sex­ual di­mor­phism in weight and body length. Males have an av­er­age mass of 4.1 kg and a length of ap­prox­i­mately 46 cm. Red­tail mon­key fe­males, in con­trast, av­er­age 2.9 kg in mass and about 38 cm in length (Torstar Books 1984; Smuts et al. 1987).

Other than size dif­fer­ences, males and fe­males of this species are very sim­i­lar. The rec­og­niz­able mark­ings of adult red­tail mon­keys in­clude a black face, bluish skin around the eyes, a white spot on the nose, and white cheek fur. The name 'red­tail' comes from the chest­nut-col­ored fur on the un­der­side of the tail. The rest of the body is cov­ered with a speck­led brown coat and gray or black limbs, de­pend­ing on the sub­species (Torstar Books 1984).

Red­tail mon­key in­fants have woolly gray fur at birth. Al­though they are born with a vis­i­ble nose spot, young red­tail mon­keys have a brown tail and no cheek whiskers. As they ma­ture, their mark­ings be­gins to re­sem­ble those of adults (King­don, 1984). (King­don, 1984; Smuts, et al., 1987; Torstar Books, 1984)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  2 to 6 kg

  4.41 to 13.22 lb

• Average mass

  males: 4.1 kg; females: 2.9 kg

  lb

• Average length

  males: 46 cm; females 38 cm

  in

Re­pro­duc­tion

Cer­co­p­ithe­cus as­ca­nius dis­plays a polyg­y­nous-promis­cu­ous mat­ing sys­tem (Cords et al., 1984). This type of mat­ing char­ac­ter­izes pop­u­la­tions in which one male mates promis­cu­ously with the fe­males of the group. Since fe­males show no out­ward signs of re­cep­tive­ness they fre­quently elicit mat­ings with males from their own group or from wan­der­ing male groups through a be­hav­ior known as pre­sent­ing (Estes, 1991). (Estes, 1991)

• Mating System
• polygynous
• polygynandrous (promiscuous)

Red­tail mon­keys gen­er­ally breed through­out the year, al­though the peak sea­son is from No­vem­ber to Feb­ru­ary (Smuts et al., 1987). The ma­jor­ity of preg­nan­cies pro­duce a sin­gle in­fant.

Al­though data are lack­ing for C. as­ca­nius, in gen­eral, species in the genus Cer­co­p­ithe­cus have ges­ta­tions rang­ing in du­ra­tion from around 5 months to a max­imun of 7 months. New­borns typ­i­cally weigh around 400 g, and are en­tirely de­pen­dent upon the mother for trans­porta­tion and nour­ish­ment (Nowak, 1999). It is rea­son­able to as­sume that C. as­ca­nius is sim­i­lar in these re­spects to other mem­bers of the genus.

Males gen­er­ally reach sex­ual ma­tu­rity at the age of six, fe­males ma­ture at four or five years of age (Smuts et al., 1987). (Smuts, et al., 1987)

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

• Breeding interval

  It is likely that females are capable of producing young each year.

• Breeding season

  Redtail monkeys generally breed throughout the year, although the peak season is from November to February

• Average number of offspring

  1

• Average number of offspring

  1

  AnAge

• Average gestation period

  6 months

• Average gestation period

  147 days

  AnAge

• Range age at sexual or reproductive maturity (female)

  4 to 5 years

• Average age at sexual or reproductive maturity (male)

  6 years

As in most pri­mates, parental care is mainly the re­spon­si­bil­ity of fe­males. Young are al­tri­cial, and must be car­ried for the first sev­eral weeks of life. Moth­ers pro­vide food (milk) for their young, as well as trans­porta­tion and groom­ing.

Fe­male guenons typ­i­cally have life-long as­so­ci­a­tions with their kin. The dom­i­nance rank of a fe­male within her so­cial group will af­fect the dom­i­nance rank of her daugh­ters. (Nowak, 1999; Smuts, et al., 1987)

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

Lifes­pan/Longevity

Al­though data are not avail­able for this species, other mem­bers of the genus Cer­co­p­ithe­cus are known to live in cap­tiv­ity for more than 30 years. It is likely that C. as­ca­nius is sim­i­lar to other mem­bers of the genus in lifes­pan. Lifes­pan in the wild is likely to be some­what shorter than it is in cap­tiv­ity. (Nowak, 1999)

• Average lifespan
  Status: wild

  30 years

• Average lifespan
  Sex: female
  Status: captivity

  25.9 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Sex: female
  Status: captivity

  28.3 years

  Max Planck Institute for Demographic Research

Be­hav­ior

This di­ur­nal, ar­bo­real species is quite agile and ac­tive. Their main hours of ac­tiv­ity are in the early morn­ing and late evening (King­don, 1984).

Red­tail mon­keys tend to be found in medium-sized groups of 11 to 14 in­di­vid­u­als con­tain­ing one male and a ma­tri­lin­eal group of fe­males (Chap­man and Chap­man, 2000). It is com­mon for sev­eral of these troops to con­gre­gate to­gether at food re­sources or in large trees dur­ing rest­ing pe­ri­ods (King­don, 1984). Groups of red­tail mon­keys travel ap­prox­i­mately 1.4 km each day in search of food.

Al­lo­moth­er­ing, the shar­ing of ma­ter­nal care by other fe­males of the group other than the in­fant's mother, has also been ob­served in red­tail mon­key groups, al­though oc­ca­sion­ally the in­fant is harmed in a fight for pos­ses­sion of the youth (Struh­saker and Le­land, 1979).

Cer­co­p­ithe­cus as­ca­nius males, upon reach­ing sex­ual ma­tu­rity, dis­perse from the home range and dis­place other males in dif­fer­ent groups or join all-male wan­der­ing bands (Cords 1984). After dis­place­ment of the tenured male, it is com­mon for the in­cum­bent male to kill all ex­ist­ing off­spring in the group, thereby mak­ing lac­tat­ing fe­males come into es­trous sooner and bear his off­spring (Struh­saker, 1977). (Chap­man and Chap­man, Aug 2000; Cords, 1984; King­don, 1984; Smuts, et al., 1987; Struh­saker and Le­land, 1979; Struh­saker, 1977)

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

• Average territory size

  12,000 m^2

Home Range

Groups de­fend their home ranges of about 120 hectares pri­mar­ily through vi­sual threats and, if nec­es­sary, phys­i­cal com­bat (Smuts et al., 1987). (Smuts, et al., 1987)

Com­mu­ni­ca­tion and Per­cep­tion

As in all pri­mates, com­mu­ni­ca­tion in this species is com­plex, and in­cludes chem­i­cal, vi­sual, au­di­tory, and tac­tile com­po­nents. The vi­sual com­mu­ni­ca­tion sys­tem con­sists of eye­brow rais­ing, fa­cial skin stretch­ing, and head-bob­bing (Estes, 1991). These sig­nals are com­monly used to warn po­ten­tial preda­tors or un­wanted in­trud­ers. Vocal com­mu­ni­ca­tion con­sists of bird­like chirps be­tween mem­bers of a group (King­don, 1984). This form of com­mu­ni­ca­tion is mainly used so­cially among mem­bers of the same unit. These as­so­ci­ated in­di­vid­u­als may also iden­tify one an­other by nose-to-nose greet­ing, in which two in­di­vid­u­als press their muz­zles to­gether. After this greet­ing they will com­monly prac­tice rec­i­p­ro­cal so­cial groom­ing or play (Estes, 1991). (Estes, 1991; King­don, 1984)

• Communication Channels
• visual
• tactile
• acoustic
• chemical

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Red­tail mon­keys are pri­mar­ily fru­giv­o­rous, but sup­ple­ment their diet with leaves, in­sects, flow­ers, buds, and gum (Torstar Books, 1984; Chap­man and Chap­man, 2000).

It is com­mon for adults to store fruit in their large cheek pouches in order to take their meal to an area free from the threat of theft by other mon­keys (Torstar Books, 1984). (Chap­man and Chap­man, Aug 2000; Torstar Books, 1984)

• Primary Diet
• herbivore
  • frugivore

• Animal Foods
• insects

• Plant Foods
• leaves
• fruit
• flowers
• sap or other plant fluids

Pre­da­tion

Cer­co­p­ithe­cus as­ca­nius is po­ten­tial prey for chim­panzees, crowned hawk-ea­gles, wild cats, and hu­mans (King­don, 1984; Le­land and Struh­saker, 1993). It is also likely that these mon­keys fall vic­tim to the same preda­tors that trou­ble other small, ar­bo­real pri­mates in African forests. These in­clude leop­ards, snakes, and a va­ri­ety of avian preda­tors. (Nowak, 1999)

• Known Predators

  • Humans
  • Chimpanzees
  • Crowned hawk-eagles
  • Leopards

Ecosys­tem Roles

Be­cause these mon­keys are fru­giv­o­rous, and can trans­port fruits in their cheek pouches, it is likely that they play some role in seed dis­per­sal. In ad­di­tion, as a prey species, they prob­a­bly have some ef­fect on preda­tor pop­u­la­tions. (Nowak, 1999)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Red­tail mon­keys have been in­stru­men­tal in the re­gen­er­a­tion of Strych­nos mitis, a tree species found in the Kibale For­est. Red­tail mon­keys feed heav­ily on the fruit of this tree. As they eat the fruit, they spit the in­tact seeds, which fall to the rain­for­est floor where the seeds can suc­cess­fully ger­mi­nate. This method of seed sow­ing pro­duces more saplings an­nu­ally than the fruit would nor­mally pro­duce with­out the help of red­tail mon­keys (Lam­bert 1995).

Red­tail mon­keys have also been use­ful as lab­o­ra­tory an­i­mals in stud­ies on var­i­ous viral dis­eases (King­don 1984).

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Cer­co­p­ithe­cus as­ca­nius reg­u­larly prac­tices crop raid­ing of nearby agri­cul­tural gar­dens con­tain­ing maize, ba­nana, mil­let, bean, pump­kin, pineap­ple, or pas­sion fruit crops (King­don, 1984). In re­gions of low pro­duc­tiv­ity this be­hav­ior has be­come a se­ri­ous prob­lem for neigh­bor­ing human vil­lages.

Red­tail mon­keys are also one of the major car­ri­ers of yel­low fever in Africa (King­don, 1984). When the mon­keys ven­ture into human vil­lages to raid their crops, there is a greater chance that an in­fected in­di­vid­ual could spread this dis­ease to the vil­lagers. (King­don, 1984)

• Negative Impacts
• injures humans
  • causes disease in humans
• crop pest

Con­ser­va­tion Sta­tus

Al­though red­tail mon­key pop­u­la­tions are cur­rently healthy, there is some con­cern about their fu­ture sta­tus. As is the case with many rain­for­est dwelling an­i­mals, the threat of habi­tat loss by de­for­esta­tion is a major con­cern. Since C. as­ca­nius in­hab­its a rel­a­tively small area on the African con­ti­nent, loss of habi­tat could be detri­men­tal for the fu­ture of this pri­mate species.

Red­tail mon­keys are also threat­ened by pre­da­tion. They are po­ten­tial prey for chim­panzees, crowned hawk-ea­gles, wild cats, and hu­mans (King­don, 1984; Le­land and Struh­saker, 1993).

Red­tail mon­key pop­u­la­tions are de­pleted by dis­traught farm­ers that view them as pests and shoot them on sight (Le­land and Struh­saker, 1993). (King­don, 1984; Le­land and Struh­saker, 1993)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  Appendix II

Other Com­ments

Red­tail mon­keys are com­monly found in close as­so­ci­a­tion with other pri­mate species, such as red colobus, mangabeys, and blue mon­keys. Red­tail mon­keys form an im­por­tant feed­ing as­so­ci­a­tion with colobus mon­keys. Colobus mon­keys bite through the tough outer skins of Mon­dura fruits and red­tail mon­keys are able to eat the fruit scraps that con­tain or­di­nar­ily un­ob­tain­able fruit pulp (Le­land and Struh­saker, 1993). They have also been ob­served to in­ter­act so­cially with other species; play­ing, groom­ing, and help­ing in de­fense from com­mon preda­tors.

Red­tail mon­keys have been ob­served to mate with blue mon­keys, and pro­duce fer­tile off­spring (Le­land and Struh­saker, 1993). (Le­land and Struh­saker, 1993)

Con­trib­u­tors

Nancy Shef­ferly (ed­i­tor), An­i­mal Di­ver­sity Web.

Sarah Davis (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Chap­man, C., L. Chap­man. Aug 2000. Con­straints on Group Size in Red Colobus and Red-tailed guenons:Ex­am­in­ing the Gen­er­al­ity of the Eco­log­i­cal Con­straints Model. In­ter­na­tional Jour­nal of Pri­ma­tol­ogy, 21 (4): 565-595.

Cords, M. 1984. Mat­ing Pat­terns and So­cial Struc­ture in Red­tail Mon­keys. Z. Tierpsy­chol, 64: 313-329.

Estes, R. 1991. The Be­hav­ior Guide to African Mam­mals. Uni­ver­sity of Cal­i­for­nia Press.

King­don, J. 1984. East African Mam­mals: An Atlas of Evo­lu­tion in Africa Vol. 1. Chicago, Il: The Uni­ver­sity of Chicago Press.

Lam­bert, J. 1995. Red­tail Mon­keys and Strych­nos mitis: A Plant-an­i­mal In­ter­ac­tion in the Kibale For­est, Uganda. In­ter­na­tional Jour­nal of Pri­ma­tol­ogy, 71(5): 353-355.

Le­land, L., T. Struh­saker. 1993. Mon­key Busi­ness. An­i­mal King­dom, 90: 24-37.

Nowak, R. 1999. Walker's Mam­mals of the World, Sixth Edi­tion. Bal­ti­more and Lon­don: The Johns Hop­kins Uni­ver­sity Press.

Smuts, B., D. Ch­eney, R. Wrang­ham, T. Struh­saker. 1987. Pri­mate So­ci­eties. Chicago, Il: The Uni­ver­sity of Chicago Press.

Struh­saker, T. 1977. In­fan­ti­cide and So­cial Or­ga­ni­za­tion in the Red­tail Mon­key. Z. Tierpsy­chol., 45: 75-84.

Struh­saker, T., L. Le­land. 1979. Ad­vances in the Study of Be­hav­ior Vol. 9. Aca­d­e­mic Press.

Struh­saker, T., T. Pope. 1991. Mat­ing Sys­tem and Re­pro­duc­tive Suc­cess - A Com­par­i­son of 2 African For­est Mon­keys. Be­hav­iour, 117: 182-205.

Torstar Books, 1984. All the World's An­i­mals-Pri­mates. New York, Toronto: Torstar Books Inc.