Cephalophus ogilbyi, Waterhouse, 1838

Don E. Wilson & Russell A. Mittermeier, 2011, Bovidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 444-779 : 723

251.

Ogilby’s Duiker

Cephalophus ogilbyi

French: Céphalophe d'Ogilby / German: Ogilby-Ducker / Spanish: Duiker de Ogilby

Taxonomy. Cephalophus ogilbyi Waterhouse, 1838 ,

Equatorial Guinea, Fernando Po.

The three species recognized here ( C. ogilbyi , C. brookei , and C. crusalbum ), were formerly included as subspecies of C. ogilby: based on physical resemblances. Monotypic.

Distribution. Bioko I ( Equatorial Guinea) and mainland Africa from E Nigeria (E of the Niger River) to W Cameroon.

Descriptive notes. Head-body 90 cm, tail 15 cm, shoulder height 56 cm; weight 18-20 kg. Ogilby’s Duiker is larger than the similar Brooke’s Duiker ( C. brookei ) and the White-legged Duiker (C. crusalbum). The hindquarters are powerful and the legs are relatively long. The coat is a deep golden brown color, darker than that of Brooke's Duiker. The rump tends to be more richly colored than the sides. The nape and sides of the neck are very sparsely haired and appear browner in color than the body. A wide zone of reversed hair occurs on the nape of the neck. The underparts are a pale golden brown. Scattered black hairs on the midline of the neck become increasingly dense between the shoulders, beginning a well-defined black dorsal stripe that runs from the shoulders to the base ofthe tail (in some individuals, the stripe remains indistinct from the shoulders until the middle of the back); this stripe is relatively narrow, typically 1.1-3 cm wide. The limbs are the same color as the body, but darken around the hooves. Dark brown stripes may be present down the fronts of the forelegs, and a dark patch is often present on the hocks. The tail has a terminal tuft of gray hair that is sometimes quite large. The cheeks are the same color as the body, but the muzzle is blackish and the forehead bright rufous. The sparse tuft of hair at the top of the head can vary from bright orange to dark brown. Both sexes of Ogilby’s Duiker bear a pair ofslightly upward-curving horns. In males they are thick, with roughened rings on the basal half, and may grow 9 cm long; those of females are approximately 6 cm in length. The convex skull has a thickened frontal boss, especially in individuals from Bioko Island. Dental formulais10/3,C0/1,P 3/3, M 3/3 (x2) = 32.

Habitat. Moist lowland forests. On Bioko Island, Ogilby’s Duikers may be found in lowland and montane forests, including the high-elevation Schefflera zone. It has been observed at elevations of 10-2260 m. Density in Korup National Park, Cameroon, and on Bioko Island was estimated at 13 ind/km?.

Food and Feeding. There is no specific information available for this species, but presumably frugivorous.

Breeding. There is no information available for this species.

Activity patterns. Diurnal. Activity begins abruptly around dawn, and stops equally abruptly at sunset. Times of greatest activity are the few hours after sunrise (6:30-11:00 h) and the late afternoon (16:00-19:00 h). Midday is usually spent sleeping. Specific resting places are used for sleeping at night; other areas are frequented during the day for foraging and midday rests.

Movements, Home range and Social organization. Solitary, although pairs (an adult and youngster) are occasionally seen. Latrine areas appear to be used. A radio-collared adult male in Korup National Park, had a home range of 0-10 km?. Several other Ogilby’s Duikers were observed within this range near the periphery, and it is unknown whether territoriality is involved.

Status and Conservation. CITES Appendix II. Classified as Vulnerable on The IUCN Red List (as C. ogilbyi ogilbyr). The total population is estimated at 12,000 animals. Ogilby’s Duikeris one of the principal sources of bushmeat on Bioko Island, representing the second most frequently used species based on biomass (over 10,000 kg are harvested per year). Current levels of harvest are likely unsustainable.

Bibliography. Butynski et al. (2001), East (1999), Fa, Juste et al. (1995), Fa, Yuste et al. (2000), Grubb (1978), Grubb & Groves (2001), Happold (1987), IUCN/SSC Antelope Specialist Group (2008m), Wilson (2001).

Figures

On following pages: 245. Eastern Bay Duiker (Cephalophus castaneus); 246. Jentink’s Duiker (Cephalophus jentinki); 247. Western Yellow-backed Duiker (Cephalophus silviculton; 248. Eastern Yellow-backed Duiker (Cephalophus curticeps); 249. Abbott's Duiker (Cephalophus spadix); 250. Black Duiker (Cephalophus niger); 251. Ogilby’s Duiker (Cephalophus ogilbyi); 252. White-legged Duiker (Cephalophus crusalbum): 253. Brooke's Duiker (Cephalophus brookel); 254. Peters's Duiker (Cephalophus callipygus).

Distribution. Bioko I ( Equatorial Guinea ) and mainland Africa from E Nigeria (E of the Niger River) to W Cameroon .