Blue monkey

Blue monkey[1]
Blue monkey in Lake Manyara National Park, Tanzania.
Conservation status
Least Concern (IUCN 3.1)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Family:	Cercopithecidae
Genus:	Cercopithecus
Species:	C. mitis
Binomial name
Cercopithecus mitis Wolf, 1822
Subspecies
6, see text
Range map (note: includes the range of the closely related Sykes', silver, and golden monkey)

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 Great Rift Valley and south to northern Angola and Zambia. It sometimes includes the Sykes', silver, and golden monkey as subspecies.^[1]

Subspecies

Several subspecies are recognised:^[1]

• Cercopithecus mitis mitis – Pluto monkey, found in Angola
• Cercopithecus mitis heymansi
• Cercopithecus mitis stuhlmanni – Stuhlmann's blue monkey
• Cercopithecus mitis elgonis – Elgon blue monkey
• Cercopithecus mitis botourlinii
• Cercopithecus mitis opitsthosticus

At times some of these have been regarded as full species, additional subspecies have been consiydered valid, while others are not recognised by all authorities.

Description

By stream in Lake Manyara National Park, Tanzania

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 are 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.

Habitat

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 the bark from exotic trees in a search for food or moisture. It is also hunted for bushmeat.

Social structure

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][5][6] Occasionally, solitary males are observed which are probably transient, having left their natal group in search of a new group (Rudran 1978).

Social relationships

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 play.^{[5][6][7][8][9]} 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 (Rudran 1978).^[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.^[9] Blue monkey females exhibit strong, aggressive competition between groups^[5][6][8] and between other species because of their territorial character^[6][8] but milder though more frequent competition within groups.^[6] Even though earlier beliefs were that blue monkeys are not territorial, more current extended research^[8] shows that earlier researched misinterpreted the results because social interactions overall are infrequent. Moreover, overall agonism rates in blue monkeys are very low.^[6][9] Within group conflicts are mild and infrequent because females tend to distance themselves from one another and feed at different sites, thus avoiding competition.^[6][9] Though it was believed that blue monkeys are egalitarian, current extended research confirms that there actually is linear dominance hierarchy in female blue monkeys,^[6][8] which becomes more apparent when food resources are scarce.^[6]

Reproduction

The mating system is polygynous, and there is a corresponding sexual dimorphism in size, with the males substantially the 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.^[10]

References

1. ^ ^{a b c} Groves, C. (2005). Wilson, D. E., & Reeder, D. M, eds. ed. Mammal Species of the World (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 157. OCLC 62265494. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3/browse.asp?id=12100475. 
2. ^ Kingdon, J., Gippoliti, S., Butynski, T. M., Lawes, M. J., Eeley, H., Lehn, C. & De Jong, Y. (2008). Cercopithecus mitis. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 4 January 2009.
3. ^ ^{a b c d e f} Förster, Steffen; Cords, Marina (2005). "Socialization of infant blue monkeys (Cercopithecus mitis stuhlmanni): Allomaternal interactions and sex differences". Behaviour 142 (7): 869–896. doi:10.1163/1568539055010138. 
4. ^ Hutchins, M., Kleiman, G.D., Geist, V., McDada, M.C. 2004. Grzimek’s Animal Life Encyclopedia. 14:2. Gale Group.
5. ^ ^{a b c} Cords, Marina (1986). "Interspecific and Intraspecific Variation in Diet of Two Forest Guenons, Cercopithecus ascanius and C. mitis". Journal of Animal Ecology 55 (3): 811–827. JSTOR 4418. 
6. ^ ^{a b c d e f g h i} Cords, Marina (2002). "Friendship among adult female blue monkeys (Cercopithecus mitis)". Behaviour 139 (2-3): 291–314. doi:10.1163/156853902760102681. 
7. ^ Gathua JM. 2000. Intraspecific variation in foraging patterns of redtail monkeys (Cercopithecus ascanius) in the Kakamega Forest, Kenya. Dissertation Abstracts International 60-12:A,4497. Columbia University.
8. ^ ^{a b c d e} Payne, H.F.P.; Lawes, M.J.; Henzi, S.P. (2003). "Fatal Attack on an Adult Female Cercopithecus mitis erythrarchus: Implications for Female Dispersal in Female-Bonded Societies". International Journal of Primatology 24 (6): 1245–1250. http://www.ingentaconnect.com/content/klu/ijop/2003/00000024/00000006/00474818. Retrieved 24 September 2010. 
9. ^ ^{a b c d} Pazol, Karen; Cords, Marina (2005). "Seasonal variation in feeding behavior, competition and female social relationships in a forest dwelling guenon, the blue monkey (Cercopithecus mitis stuhlmanni), in the Kakamega Forest, Kenya". Behavioral Ecology and Sociobiology 58 (6): 566–577. doi:10.1007/s00265-005-0953-3. 
10. ^ Ghiglieri, Michael. East of the Mountains of the Moon: Chimpanzee Society in the African Rain Forest, The Free Press, 1988, pg. 238.