Cercopithecus mitis, Wolf, 1822

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cercopithecidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 550-755 : 693-694

78.

Blue Monkey

Cercopithecus mitis

French: Cercopitheque a diademe / German: Diademmeerkatze / Spanish: Cercopiteco azul

Other common names: Diademed Guenon, Diademed Monkey; Boutourlini's Blue Monkey (boutourlinii), Elgon Blue Monkey (elgonis), Lomami River Blue Monkey (heymansi), Pluto Monkey (mitis), Rump-spotted Blue Monkey (opisthostictus), Schouteden’s Blue Monkey (schoutedeni), Stuhlmann’s Blue Monkey (stuhlmanni)

Taxonomy. Cercopithecus mitis Wolf, 1822 ,

Guinea, but possibly Angola according to P. Napier in 1981.

The taxonomy of the highly polytypic “ mitis ” group of guenonsis still unsettled and varies according to author. In his 1997 Field Guide to African Mammals J. Kingdon aligned C. nictitans with C. mutis comprising a “gentle monkey,” C. nictitans superspecies group. C. mutis in this arrangement included four clusters: Mitis monkeys, white-throated monkeys (includes albogularis ), silver monkeys (includes doggetti and kandti ), and a cluster that includes the forms stuhlmanni, elgonis, and boutourlini—22 taxa in all. This arrangement was followed in The Mammals ofAfrica (Volume 2) edited by T. Butynski and colleagues (published in 2013). P. Grubb and colleagues in 2003 also used the arrangement of Kingdon with just two species in the C. nictitans group: C. nictitans (with two subspecies) and C. mutis (with 16 subspecies, including albogularis , doggetti , and kandti ). C. P. Groves in his 2001 Primate Taxonomy placed C. mutis (with seven subspecies) as one of five species that make up his C. mitis species group, the other species being C. nictitans (with five subspecies), C. doggetti , C. kandti , and C. albogularis (with twelve subspecies). Natural and anthropogenic hybridizations have been reported: C. m. stuhlmanni x C. m. kolbi (natural) and C. m. stuhlmanni x C. ascanius schmadti, C. m. stuhlmanni x C. albogularis , C. m. stuhlmannii x C. m. schoutedeni, C. m. stuhlmannii x C. m. opusthostictus, C. m. stuhlmanni x C. m. kandti , C. m. stuhlmannii x C. doggetti , C. m. heymansi x C. m. opisthostictus (anthropogenic). Seven subspecies recognized.

Subspecies and Distribution.

C.m.mitisWolf,1822—WAngola.

C.m.boutourliniiGiglioli,1887—SWEthiopia,fromLakeTanaSalongtheWsideoftheEthiopianRifttoNofLakeTurkana.

C.m.elgonisLonnberg,1919—WKenya(MtElgon).IntermediatesbetweenthesubspecieselgonisandstuhlmanniiarefoundinKakamegaForestandontheeasternflanksoftheRuwenzoriMts.

C.m.heymansiColyn&Verheyen,1987—EDRCongo(betweentheLomaniandLualabarivers,reachingtoc.2°S,andextendingslightlytotheWoftheLomaniRiver).

C.m.opusthostictusSclater,1894—SEDRCongo(fromc.6°NontheWbankoftheLualabaRiverStoKatangaProvince,andWtotheLakeTanganyika),NZambia(WoftheLuangwaRiver),andEAngola.

C.m.schoutedeniSchwarz,1928—EDRCongo,typicallyonIdjwiandShushuislandsinLakeKivu;onthemainland,specimensarefromtheWVirungaVolcanoesandasfarSWasBobandana,althoughthesestronglytendtowardthesubspeciesstuhlmanni.

C. m. stuhlmanni Matschie, 1893 — S South Sudan (Didinga Hills and Imatong Mts), Uganda (N in Bunyoro, E in Tororo, and in the W), W Kenya (W of the Rift Valley, including Mt Elgon and Kakamega Forest), and NE DR Congo, from the region between the Uele and the Congo rivers, from the Itimbiri River E to the Ituri and Semliki Forests, and S to the LLualaba River c.6° S.

Descriptive notes. Head—body 46-71 cm (males) and 39-59 cm (females), tail 60— 95 cm (males) and 49-88 cm (females); weight 5.9-9 kg (males) and 2.7-5.5 kg (females). Males are much larger than females. The Blue Monkey is a large, variable species, characterized by its “diadem” of dense pale (usually white) fur on the forehead. Upper body is speckled blue-gray, with dark blackish limbs (particularly arms) and a broad band joining them across the scapular region. Nape and crown are dark gray or black, with a pale diadem in front and long, rounded, pale cheek whiskers and short chin hairs. Tail is carried high in a slight downward curve. The “Pluto Monkey” (C. m. matis) 1s dark gray above, with white-gray speckling; black limbs, underside, and proximal half oftail; dark crown and nape, banded in agouti and often continuing as a broad, black interscapular band in sharp contrast to frontal band, centrally broad and narrowing laterally; and dark gray cheek whiskers, with alternating black and white bands. Its hairs are gray at the base, with four alternating pairs of white and black bands. The “Lomami River Blue Monkey” (C. m. heymanst) has a blue-gray nape, crown, and shoulders, with a lighter underside than upper side; a contrasting narrow white frontal diadem; a crown that is annulated and continuous with the similarly colored mantle; and black arms. In “Schouteden’s Blue Monkey” (C. m. schoutedeni), pelage is long and thick, distinguished from “Stuhlmann’s Blue Monkey” (C. m. stuhlmanni) by its pale gray-olive color; crown, nape, and terminal half of tail are black; and it has a white-speckled frontal band. Stuhlmann’s Blue Monkey has a black crown with contrasting diadem of even width across its forehead;it is usually gray flecked with black; legs, sometimes partially black, are darker than mantle; and underside is lighter than upper side. Hairs on its body have three to five white or yellowish-white/black band pairs. There are differences according to elevation, with a blackish interorbital region in mountains west of Lake Victoria, rare in those from lower elevations. High-elevation specimens also have more developed cheek whiskers and a generally white zone from chin to nose. In the mountains of the Semliki Valley, ear tufts, which are ocher in more westerly populations, are usually white. The “Elgon Blue Monkey” (C. m. elgonis) is distinguished from Stuhlmann’s Blue Monkey by lack of ear tufts, very dark legs, black ventral color, and black collar on the neck. “Boutourlini’s Blue Monkey” (C. m. boutourlinu) differs from Stuhlmann’s Blue Monkey in that light bands of hair are yellow rather than white, with either four or five band pairs; frontal band blends with crown; and arms, legs, underside, and terminal three-quarters of tail are black. Pelage has been described as intermediate between that of Stuhlmann’s Blue Monkey and the “Rump-spotted Blue Monkey” (C. m. opisthostictus). The Rump-spotted Blue Monkeyis a light gray on body and legs, darker on crown and nape; arms, underside, and terminal half to three-quarters oftail are black; tail is sometimes reddened below, especially in juveniles; and there are three white/black band pairs.

Habitat. A variety of forests including gallery forests in wooded savanna (especially the Pluto Monkey and Stuhlmann’s Blue Monkey), lowland evergreen rainforest, riparian, montane, semi-deciduous, coniferous, coastal, swamp, secondary growth forest, and dry scrubland. Elevational range is 750-3300 m. The Elgon Blue Monkey is found up to 3800 m in the Rwenzori Mountains.

Food and Feeding. Blue Monkeys have been described as dietary generalists. In lowland-type rainforest near the Equator, they are described as predominantly frugivorous, eating both ripe and unripe fruit. In regions that experience pronounced seasonality, they are reported to have more varied diets that include young and mature leaves, buds, flowers, shoots, nectar, gum, seeds, lichen, insects, and other invertebrates (primarily arthropods). A study of four groups of Blue Monkeys at Kanyawara indicated a balance of leaves (c.33%), fruit (c.28%), and insects (c.38%), with flowers contributing ¢.3-8%.

Breeding. Sexual maturity is reached at 4-6 years of age. The ovarian cycle is ¢.30 days. The gestation period is 5-6 months, after which usually a single infant is born. Infants are cared for by the mother and other females in a group (allomothering). Infanticide has been reported. Individuals live for 20 years, on average, but are known to live longer.

Activity patterns. Blue Monkeys are diurnal and arboreal. Locomotion is mainly quadrupedal. Between 13% and 35% of their time is spent climbing, with vertical clinging and leaping reported at ¢.3%. More than 50% percent of their time is spent at heights of 10-20 m in the forest canopy. About 40% oftheir time is spent at heights of 5-10 m, with 3% spent between the ground and 5 m and 3% on the ground.

Movements, Home range and Social organization. Home ranges vary in size according to habitat type and are c.20-300 ha. Daily movement averages 1300 m. Average group size is 18 individuals. Blue Monkeys live in patriarchal, unimale-multifemale groups. Mating is polygynous. Males disperse from their natal groups, and females are philopatric.

Status and Conservation. CITES Appendix II. Classified as Least Concern on The IUCN Red List, including the subspecies opisthostictus and stuhlmanni. Subspecies schoutedeni is listed as Critically Endangered, boutourlinii as Vulnerable, heymansi as Near Threatened, and mutis as Data Deficient. The subspecies elgonis has not been assessed. The Blue Monkey is listed as Class B in the African Convention on the Conservation of Nature and Natural Resources. It is generally common throughout its distribution, but it is threatened to some degree by deforestation, habitat fragmentation, and hunting for food and traditional medicine in some places. Some subspecies with restricted distributions are threatened to varying degrees. There is no recent information on the status of the Pluto Monkey. In his 1997 field guide, J. Kingdon wrote that it was possibly extinct due to its having a small distribution in an area densely populated with humans. It is a priority for further survey work. The Lomami River Blue Monkey is threatened by commercial bushmeat hunting and an expanding bushmeat market. It is limited to forests between the Lomami and Lualaba rivers—highly accessible from Kisangani. Its population status is not known, butit is expected to have experienced declines in the order of 20-25% over the past 27 years (three generations) as a result of the bushmeat trade. Recent surveys of Schouteden’s Blue Monkey on the two islands where it is native have indicated that very little natural forest remains and deforestation was ongoing. No primate sightings were reported during those surveys. If Schouteden’s Blue Monkey does survive on these islands, it is likely that its numbers are very low; the status of a mainland subpopulation is questionable because it is unclear that one ever existed there. The distribution of Stuhlmann’s Blue Monkey is largely continuous in central Africa, although it is disjunct in its eastern parts. At present, the population is not believed to be declining at a rate that would warrant threatened status, although it is suffering from hunting, deforestation, and habitat degradation in some areas. Boutourlini’s Blue Monkey is restricted to tropical deciduous and riparian forests, and these habitats are threatened by extensive and uncontrolled logging for timber and agriculture. Given the extent of habitat loss, it may qualify for a higher threatened status. The Rump-spotted Blue Monkey has an extensive distribution and is widely distributed and locally common. Although it is decreasing because of habitat loss and degradation and hunting, these impacts are not believed to be resulting in a decline that would warrant listing in a threatened category. The Blue Monkey occurs in numerous protected areas acrossits distribution.

Bibliography. Aldrich-Blake (1970), Beeson (1989), Butynski (1982b, 1990), Butynski, Chapman et al. (1992), Butynski, Kingdon & Kalina (2013), Cords (2002), Detwiler (2002), Ekernas & Cords (2007), Fairgrieve & Muhumuza (2003), Forster & Cords (2006), Groves (2001, 2005b), Grubb et al. (2003), Kaplin & Moermond (2000), Kingdon (1997), Kingdon, Gippoliti, Butynski, Lawes et al. (2008), Lawes et al. (1990), Rudran (1978), Schlichte (1978), Struhsaker (1978), Struhsaker et al. (1988), Tweheyo & Obua (2001), Wimberger et al. (2011).

Figures

77. Putty-nosed Monkey (Cercopithecus nictitans), 78. Blue Monkey (Cercopithecus matis), 79. Silver Monkey (Cercopithecus doggetti), 80. Virungas Golden Monkey (Cercopithecus kandi)

Subspecies and Distribution. C.m.mitisWolf,1822—WAngola. C.m.boutourliniiGiglioli,1887—SWEthiopia,fromLakeTanaSalongtheWsideoftheEthiopianRifttoNofLakeTurkana. C.m.elgonisLonnberg,1919—WKenya(MtElgon).IntermediatesbetweenthesubspecieselgonisandstuhlmanniiarefoundinKakamegaForestandontheeasternflanksoftheRuwenzoriMts. C.m.heymansiColyn&Verheyen,1987—EDRCongo(betweentheLomaniandLualabarivers,reachingtoc.2°S,andextendingslightlytotheWoftheLomaniRiver). C.m.opusthostictusSclater,1894—SEDRCongo(fromc.6°NontheWbankoftheLualabaRiverStoKatangaProvince,andWtotheLakeTanganyika),NZambia(WoftheLuangwaRiver),andEAngola. C.m.schoutedeniSchwarz,1928—EDRCongo,typicallyonIdjwiandShushuislandsinLakeKivu;onthemainland,specimensarefromtheWVirungaVolcanoesandasfarSWasBobandana,althoughthesestronglytendtowardthesubspeciesstuhlmanni. C. m. stuhlmanni Matschie, 1893 — S South Sudan (Didinga Hills and Imatong Mts), Uganda (N in Bunyoro, E in Tororo, and in the W), W Kenya (W of the Rift Valley, including Mt Elgon and Kakamega Forest), and NE DR Congo, from the region between the Uele and the Congo rivers, from the Itimbiri River E to the Ituri and Semliki Forests, and S to the LLualaba River c.6° S.