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Blue monkeys are a social species. An interesting aspect of the interspecific relations of blue monkeys is their involvement in mixed groupings consisting of two or more primate species (Rudran, 1978). Blue monkey associations with redtails and red colobus sometimes last for six to seven hours within a day (Rudran, 1978). Often, blue monkeys will associate with other species to form coalitions against other groups, to help find food, and also for added protection against predators. With polyspecific associations groups are able to cover a larger area when foraging for food. They are also able to get a broader view of a large area and warn of an approaching predator by alarm calls.
As in other species of primates, communication in these monkeys is likely to be complex and varied. Because of their facial markings, facial expressions are extremely marked. Body postures add to the visual signals used in communication. Vocalizations are common in primates and are probably used by diademed monkeys. Tactile communication occurs between mates and rivals, as well as between mothers and their offspring. Grooming is an important physical activity which helps to solidify social bonds.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Survival threats to blue monkeys include habitat destruction, such as the clearing of rain forests. Blue monkeys are also destroyed for eating cultivated crops or destroying exotic trees (Fleagle, 1988).
US Federal List: threatened
CITES: appendix ii
IUCN Red List of Threatened Species: least concern
Blue monkeys eat cultivated crops and destroy exotic trees.
Negative Impacts: crop pest
In Uganda, blue monkeys are hunted for their meat (Fleagle, 1988).
Positive Impacts: food
As a prey species, these monkeys probably have some impact on predator populations. In addition, they are likely to be important in seed dispersal because of their frugivory.
Blue monkeys are frugivorous and folivorous in nature, eating mainly fruits and leaves. In addition, blue monkeys tend to concentrate their invetebrate feeding on slow-moving slugs and worms (Rudran, 1978).
Animal Foods: mollusks; terrestrial worms
Plant Foods: leaves; fruit
Primary Diet: herbivore (Folivore , Frugivore )
Cercopithecus mitis is found in rain forests of central, eastern, and southern Africa. The species can also be found in the Congo basin.
Biogeographic Regions: ethiopian (Native )
Cercopithecus mitis is found in a variety of habitats. They are very dependent upon humid, shaded areas with abundant water and tall trees which provide both food and shelter.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest ; scrub forest
Longevity for this species has not been reported, but if C. mitis is like other members of the genus Cercopithecus, the maximum lifespan is probably around 20 years.
Average lifespan
Sex: female
Status: captivity: 25.0 years.
Average lifespan
Sex: female
Status: captivity: 27.1 years.
Blue monkeys are small (ranging in weight from 4 to 6 kg) and arboreal. The face is nearly naked, usually dark in color (infrequently blue), and has well-developed musculature (Lawlor, 1979). Cercopithecus mitis is also known as the diademed monkey because it has a prominent row of forward pointing white fur just above its brow line (Rudran, 1978).
White whiskers are well developed in males. Males are larger than females. Male canines are also slightly larger than the female canines (Rudran,1978).
These monkeys are catarrhine; the nostrils are close together and they face downward. They have cheek pouches to carry food while foraging (Rudran, 1978).
The dental formula of C. mitis is 2/2 1/1 3/3 2/2=32.
The nail on each digit is flattened, and the pollex is opposable (Lawlor, 1979).
The upper parts of the body are gray and the limbs are darker in appearance. Some young have indistinct russet-colored rump patches, which has not been seen in adults (Dorst and Dandelot, 1970).
Range mass: 4 to 6 kg.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average basal metabolic rate: 19.276 W.
As is true for other forest dwelling monkeys, C. mitis likely falls prey to leopards. Other potential predators include snakes and birds of prey.
Known Predators:
Blue monkeys have a polygynous mating system, although promiscuous mating has been known to occur (Estes, 1991). Females solicit copulation from the males using body language (Estes, 1991). Females present their hindquarters to a male to indicate that they are ready to copulate. During copulation, females pout, looking over their shoulder at the male.
Mating System: polygynous ; polygynandrous (promiscuous)
Breeding occurs throughout the year. The gestation period lasts 5 months (Rudran, 1978). The female gives birth to a single offspring. The young are weaned at about six months and reach sexual maturity at about three years (Grzimck, 1990).
Breeding interval: Females are capable of producing young annually if food is available.
Breeding season: Breeding occurs throughout the year.
Average number of offspring: 1.
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 (male): 3 years.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Average birth mass: 366.4 g.
Average gestation period: 132 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (male)
Sex: male: 1673 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1673 days.
The young are relatively well developed at birth, with open eyes and the capability to grasp their mother and support their own weight (Macdonald, 1984). Females provide their young with milk for about six months. Allomaternal care does occur amongst the female troup members (Bourliere and Bertrand, 1970).
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); extended period of juvenile learning
The blue monkey or diademed monkey (Cercopithecus mitis) is a species of Old World monkey[3][4] native to Central and East Africa, ranging from the upper Congo River basin east to the East African Rift and south to northern Angola and Zambia. It sometimes includes Sykes', silver, and golden monkeys as subspecies.[1]
Several subspecies are recognised:[1]
At times, some of these have been regarded as full species, and additional subspecies have been considered valid, while others are not recognized by all authorities.
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C. m. stuhlmanni
Kakamega Forest, Kenya
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C. m. stuhlmanni
Kakamega Forest, Kenya
Despite its name, the blue monkey is not noticeably blue; it has little hair on its face, and this does sometimes give a blue appearance, but it never has the vivid blue appearance of a mandrill, for example. It is mainly olive or grey apart from the face (which is dark with a pale or yellowish patch on the forehead – the "diadem" from which the species derives its common name), the blackish cap, feet, and front legs, and the mantle, which is brown, olive, or grey depending on the subspecies. Typical sizes range from 50 to 65 cm in length, (not including the tail, which is almost as long as the rest of the animal), with females weighing a little over 4 kg and males up to 8 kg.[6]
The blue monkey is found in evergreen forests and montane bamboo forests, and lives largely in the forest canopy, coming to the ground infrequently. It is very dependent on humid, shady areas with plenty of water. It eats mainly fruit and leaves, but will take some slower-moving invertebrates. It prefers to live in tall trees, which provide both food and shelter, and is, therefore, like almost all guenons, suffering from the loss of its natural habitat. Where pine plantations replace natural forest, the monkey may be treated as a threat by foresters, since it sometimes strips bark from exotic trees in a search for food or moisture.[7] It is also hunted for bushmeat.
Blue monkeys eat fruits, figs, insects, leaves, twigs, and flowers.[8] "They are primarily frugivores, with 50% of their diet consisting of fruit, with leaves or insects as their main source of protein, with the rest of the diet being made up of seeds, flowers, and fungi. They rarely eat vertebrates. They eat a variety of plants, but concentrate on a few species, which means their population density is generally dependent on plant species' richness and diversity".[9]
Cercopithecus mitis joins with the C. ascanius (red-tailed monkey) for extra protection.[10] Its interactions with red-tailed monkeys include interspecies grooming.[11] Their social system is mainly female because the males leave once they are mature.[12] The males have little to no interaction with the young. C. mitis is very territorial, so the young males must leave quickly to help themselves become more successful. They challenge the dominant male of another family. If they defeat the dominant male, they take over the leadership of that family, and this offers a place to live, socialization, and food supplies for the young males."[13] C. mitis is said to be nomadic.
The blue monkeys live in female-philopatric social systems where females stay in their natal groups, while males disperse once they reach adulthood.[3] As a result, blue monkey groups usually consist of one male with several females and infants, giving rise to matrilinear societies.[3][14][15] Occasionally, solitary males are observed, which are probably transient, having left their natal group in search of a new group.[7][16][17]
In these female-bonded societies, only 5–15% of monkeys' activity budget is occupied by social interactions and the most common social interactions within a group are grooming and playing.[14][15][18][19][20] Relationships between group members vary: infants interact most frequently with their peers and adult or juvenile females[3] and are rarely seen near adult males.[7][3]
Alloparenting is common among blue monkeys. The most common infant handlers are juvenile females, and usually one infant is carried by a number of alloparents. One hypothesis is that this allows the infant to learn to socialise at an early stage in life.[3]
Interesting female-female relationships exist among blue monkeys. This relationship is believed to be shaped by their feeding ecology, which, in turn, is shaped by between-group and within-group competition.[20] Blue monkey females exhibit strong, aggressive competition between groups[14][15][19] and between other species because of their territorial character,[15][19] but milder though more frequent competition within groups.[15] Though earlier beliefs were that blue monkeys are not territorial, more current extended research[19] shows that earlier researchers misinterpreted the results because social interactions overall are infrequent. Moreover, overall agonism rates in blue monkeys are very low.[15][20] Within-group conflicts are mild and infrequent because females distance themselves from one another and feed at different sites to avoid competition.[15][20] Although blue monkeys were believed to be egalitarian, current extended research confirms that linear dominance hierarchy occurs in female blue monkeys,[15][19] which becomes more apparent when food resources are scarce.[15]
The mating system is polygynous, with a corresponding sexual dimorphism in size, as the males are the substantially larger sex. Females normally give birth every two years, during the onset of the warm, rainy season; gestation is around five months, and the infants are born with fur and with their eyes open. Group sizes range from 10 to 40, containing only a single adult male. It is often found in groups with other species of monkeys such as the red-tailed monkey and various red colobus monkeys.[21]
C. mitis males mate with more than one female, but the females only mate with one male. The female attracts males to copulate with her through body language. They breed throughout the year.[22] "The groups can have up to 40 members and the females usually help to care for all of the young, not just their own."[23]
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The blue monkey or diademed monkey (Cercopithecus mitis) is a species of Old World monkey native to Central and East Africa, ranging from the upper Congo River basin east to the East African Rift and south to northern Angola and Zambia. It sometimes includes Sykes', silver, and golden monkeys as subspecies.
