Cercopithecus doggetti Pocock 1907

79.

Silver Monkey

Cercopithecus doggetti

French: Cercopitheque de Doggett / German: Silbermeerkatze / Spanish: Cercopiteco plateado

Other common names: Ankole Blue Monkey, Doggett’s Blue Monkey, Doggett’'s Guenon, Doggett's Monkey

Taxonomy. Cercopithecus doggetti Pocock, 1907,

south-western Ankole, Uganda.

C. doggetti 1s a member of the mitis species group of guenons, but its taxonomy remains unsettled and varies according to author. J. Kingdon in his 1997 Field Guide to African Mammals, P. Grubb and colleagues in their review of 2003, and the The Mammals ofAfrica of 2013 edited by T. Butynski and colleagues, place C. doggetti as a subspecies of C. mitis. C. P. Groves in his 2001 Primate Taxonomy classified C. doggetti as a distinct species, which is followed here. Hybridization with C. matis stuhlmanni is reported from the Bwindi Forest and C. ascanius in Gombe Stream National Park, Tanzania. Other hybridizations include C. doggetti x C. denti and C. doggetti x C. kandti. Monotypic.

Distribution. E DR Congo, mountains W of the lakes Edward and Tanganyika (S limit reported at 3° 52° S, 28° 55" E) extending well W of the main highlands at Nyakanyendje (2°24°S, 28° 18’ E), and into S Uganda, Rwanda, Burundi (E between lakes Kivu and Tanganyika), and NW Tanzania (Bukoba District).

Descriptive notes. The only available body measurements are from a single adult female head-body 48-7 cm, tail 65-5 cm (provided by Pocock in 1907). The Silver Monkey is similar to the Blue Monkey (C. mitis), but its pelage is light silvery-brown. Crown, nape, and terminal one-third oftail are black. Tail of the Silver Monkey is often reddish underneath—a distinguishing feature. A buff-speckled frontal band contrasts with a black crown. Body hairs are gray at their base, with five to nine bands of alternating yellow and black; four band pairs occur on the throat.

Habitat. Primary forest, secondary growth forest, and montane forests. The Silver Monkey is also present in edge habitats, although they use mature forests habitats more frequently. B. A. Kaplin reported Silver Monkeys in bamboo forest. They are found at elevations between 770 m in Gombe Stream National Park in Tanzania and 2700 m in Nyungwe Forest Reserve, Rwanda. Rainfall averages 1744 cm/year in areas where they have been studied.

Food and Feeding. Silver Monkeys are dietary generalists, but fruit makes up almost 50% of their diets. Insects make up a considerable proportion of their diets, reported to be 27% in a study in Rwanda in 1998. They eat young and mature leaves, seeds, flowers, mosses, lichens, gum, and fungi. Insects in their diets include termites, grasshoppers, ants, grubs from rotting wood, and spittlebugs (hemipteran nymphs, Cercopoidea). Dietary diversity increases with decreased fruit availability. Groups living in swamps and riparian forests feed on soft stems of papyrus.

Breeding. There is no specific information available for this species, but breeding is assumed to be similar to the Blue Monkey.

Activity patterns. Silver Monkeys are diurnal and arboreal, spending 5% oftheir time at heights above 20 m in the forest canopy, more than 50% of their time at 10-20 m, 35% at 5-10 m, 3% between the ground and 5 m, and 2% on the ground. Locomotion is quadrupedal and includes climbing and leaping.

Movements, Home range and Social organization. Silver Monkeys show fidelity to their home ranges, which were 23-28 ha in a study in Nyungwe Forest Reserve, Rwanda. Daily movements are relatively long, like those of Blue Monkeys,at ¢.1300 m. They live in patriarchal, unimale-multifemale social groups of 20-30 individuals. An isolated group in gallery forest in South Ankole grew from 15 to 64 individuals over ten years. Males emigrate from natal groups. Groups may have peripheral males in addition to the dominant male.

Status and Conservation. CITES Appendix II. Classified as Least Concern on The [UCN Red List (as C. mitis doggetti). Nevertheless, the Silver Monkey occurs in a region of major habitat loss due to expanding human settlement and agriculture, and it is experiencing a decreasing population trend. Because it is found in several important conservation areas, this decline is not considered to be severe enough to justify its listing in a threatened category.

Bibliography. Butynski, Kingdon & Kalina (2013), Detwiler et al. (2005), Groves (2001, 2005b), Grubb et al. (2003), Hill (1966), Kaplin (2001, 2011), Kaplin & Moermond (2000), Kaplin et al. (1998), Kingdon (1997). Kingdon & Butynski (2008a), Tosi et al. (2005b).