Allochrocebus lhoesti (Sclater, 1899)

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 : 675

56.

L’Hoest’s Monkey

Allochrocebus lhoesti

French: Cercopitheque de L'Hoest / German: Vollbartmeerkatze / Spanish: Cercopiteco de L'Hoest

Other common names: Mountain Monkey

Taxonomy. Cercopithecus lhoesti Sclater, 1899 ,

Congo (= DR Congo). Restricted by R. Pocock in 1907 to Tschepo River, near Stanleyville (= Kisangani).

A. lhoesti 1s sympatric with Cercopithecus hamlyn: and C. mitis , in their respective distributions. Monotypic.

Distribution. E DR Congo (from the Lualaba River E to the Ituri Forest, with an additional population S of the lower Lindi River), SW Uganda, Rwanda, and N Burundi.

Descriptive notes. Head-body 54-70 cm (males) and 45-55 cm (females), tail 50-76 cm (males) and 46-67 cm (females); weight 6-10 kg (males) and 3.4-5 kg (females). Coat of L'Hoest’s Monkey is dense and black (there is some gray ticking on crown and nape), and limbs, flanks, and underside are also black. There is a short, oval-shaped, orangespeckled saddle on the lower back that stops short of the tail base. Except for a dark muzzle, face is gray; lighter coloring surrounds eyes and cheeks. These hairs are gray at the base, with four pairs of white and black bands. This differs from Preuss’s Monkey (A. preussi ), which has only two pairs ofalternating black and white bands. L’"Hoest’s Monkey has bushy white cheek whiskers and a white throat ruff. Ears are visible. Tail is gray above exceptfor the terminal one-fourth, which is black and tufted, and its ventral surface tends to be light in color. Tail of L’Hoest’s Monkey is sometimes said to be “partially prehensile,” but this belief is based on the fact that it is normally carried with a pronounced hook nearthe tip. Feet are narrow and well adapted for running on the ground. Several features of the anatomy of L’Hoest’s Monkey are associated with terrestrial adaptations. Scrotum is light blue, and females lack a sexual swelling.

Habitat. A variety of forest types, including lowland, riparian, submontane, montane, and dry woodland forests. 'Hoest’s Monkeys are occasionally found in cultivated land. They normally live at elevations of ¢.1000-2500 m, although they have been recorded up to 2900 m. Forthis reason, L'Hoest’s Monkeys, and closely related Preuss’s Monkeys, are often called “Mountain Monkeys.” Because they are largely terrestrial, they eat many fruits and seeds from shrubs and secondary tree species and thus tend to be generalists in their use of habitat types.

Food and Feeding. I.’Hoest’s Monkeys are omnivorous, eating terrestrial herbs, fruits, seeds, young leaves, flowers, berries, insects, bird eggs, wood,lichens, sap, and arthropods. About 25-45% of their waking hours are spent feeding and foraging (this varies by location). In a study in Nyungwe Forest National Park, Rwanda, terrestrial herbaceous vegetation made up more than 35% ofthe diet, with fruits comprising only 24%. The top three food items (50% of the diet) were terrestrial herbs (several species) and seeds of Macaranga neomildbraediana and Alchornea hirtella (both Euphorbiaceae ). In contrast, a population studied in Kalinzu National Park, Uganda, spent 66% ofits feeding time on invertebrates. At both sites, L'Hoest’s Monkeys ate more invertebrate species in the dry season than at other times of the year. These findings underscore the broad environmental adaptability of L’Hoest’s Monkey. Unfortunately, they occasionally raid crops from nearby villages, thus placing them at risk from retaliation from humans.

Breeding. Reproductive activities of L’Hoest’s Monkeys are seasonal. Births tend to occur at the end of dry season (November—April). After a gestation of ¢.5 months, a single infant is usually born at night. Newborns are born uniformly brown, without the ticking pattern. They acquire adult coloration over the first 2-3 months oflife. The interbirth interval is c.2 years.

Activity patterns. [.'Hoest’s Monkeys are diurnal and mostly terrestrial. They make limited use of arboreal space for foraging, avoiding predators, and sleeping. They choose a wide variety of sleeping sites compared with sympatric Blue Monkeys ( Cercopithecus mitis ). A study group in Rwanda spent 38% ofits time on the ground and only 27% in upper tree canopies. They spend an average of 45% of their time during the day foraging and feeding.

Movements, Home range and Social organization. Group sizes of I. Hoest’s Monkeys are usually 10-17 individuals, although a study group in Nyungwe Forest National Park, Rwanda, numbered 29. Groups typically include only one mature male, several adult females, and their offspring. In the Rwandan study, the home range was 116-6 ha. The monthly travel distance covered 24-70% of the home range. As expected, ranging patterns were altered by changes in availability of fruit sources, but there was not a significant seasonal influence, and rainfall was not related to travel distance in the Rwandan study. Groups are territorial; intergroup encounters usually involve chasing and vocalizing, often lasting for more than one hour.

Status and Conservation. CITES Appendix II. Classified as Vulnerable on The [UCN Red Last (as Cercopithecus lhoesti ). I’ Hoest’s Monkey is listed as a Class B species of the African Convention on the Conservation of Nature and Natural Resources and protected by national legislation in Burundi, Rwanda, and Uganda. It is threatened by deforestation on the eastern edge ofits distribution. This habitat destruction is mainly a consequence of agricultural expansion, resulting in frequent opportunities for crop raiding and other conflict with people. L'Hoest’s Monkey is also hunted for its meat and fur in some areas. Its relatively large size and terrestrial habits make it vulnerable to snaring and shotgun hunting. It is also an important prey for Leopards (Panthera pardus) in the Ituri Forest. It is known to occurin at least eleven protected areas: Kibira National Park in Burundi; Kahuzi-Biéga and Virunga national parks, Okapi Wildlife Reserve, and Tayna Gorilla Reserve in DR Congo; Nyungwe Forest National Park in Rwanda; and Bwindi Impenetrable, Kibale Forest, and Ruwenzori national parks and Kalinzu and Maramagambo forest reserves in Uganda. Because the entire distribution of L'Hoest’s Monkey is currently in a region of political and military conflict, declining populations are expected to continue. Given a 10year generation time, the overall population reduction may exceed 40% over a 30year timeframe. Controlling bushmeat hunting and improved land and water management are among the recommended conservation actions.

Bibliography. Barakabuye et al. (2007), Gautier et al. (2002), Gebo & Sargis (1994), Groves (2001), Harrison (1988a), Hart, Butynski & Hall (2008), Hart, Katembo & Punga (1996), Kaplin (2001, 2002), Kaplin & Moermond (1998, 2000), Pocock (1907), Tashiro (2006), Ukizintambara & Kaplin (2011).

Figures

49. Patas Monkey (Erythrocebus patas), 50. Grivet Monkey (Chlorocebus aethiops), 51. Tantalus Monkey (Chlorocebus tantalus), 52. Green Monkey (Chlorocebus sabaeus), 53. Malbrouck Monkey (Chlorocebus cynosuros), 54. Vervet Monkey (Chlorocebus pygerythrus), 55. Bale Mountains Monkey (Chlorocebus djamdjamensis), 56. L’Hoest’s Monkey (Allochrocebus lhoesti), 57. Preuss’s 9 Monkey Allochrocebus (null), 58. Sun-tailed Monkey (Allochrocebus solatus)

Distribution. E DR Congo (from the Lualaba River E to the Ituri Forest, with an additional population S of the lower Lindi River), SW Uganda, Rwanda, and N Burundi.