Two subspecies are generally recognized: Ogilby's duiker (Cephalophorus ogilbyi ogilbyi) from Bioko Island and the adjacent mainland of Nigeria and Cameroon, and the white-legged duiker (C. o. crusalbum) from Gabon and Congo. Brooke's duiker (Cephalophorus brookei) is sometimes included as a subspecies of C. ogilbyi. Here, it is treated as a separate species.

Head and body length: 85-115 cm

Shoulder height: 55 cm

Tail length: 12-16 cm

Adult weight: 14-20 kg

This is a long-legged duiker with powerful hindquarters. The overall color is golden brown, although the belly is paler. A thin black stripe (1-6 cm wide) runs along the midline of the back, beginning at the shoulders and narrowing to a thin line as it continues onto the tail. The tail is otherwise golden brown on top and white underneath, with a tuft of mixed white, black, and brown hairs at the tip. The legs are usually darker than the body, except in C. o. crusalbum, where the lower legs are bright white. The ochre face has a dark muzzle, white lower jaw, and distinct chestnut eyebrows. The forehead is bright rufous in color, topped with a sparse crest of longer hairs. Both sexes bear short, upward-curving horns that grow 8-12 cm long in males and 4-6 cm long in females.

Similar species
In the field, "red duikers" are often difficult to tell apart, especially as they flee. Even photographs can be a challenge, depending on the angle. The relatively pale golden coloration and narrow dorsal stripe are the most distinctive features of Ogilby's duiker. The white legs of the white-legged duiker (subspecies C. o. crusalbum) are diagnostic.

• Ogibly's duiker is very similar to Brooke's duiker (Cephalophorus brookei) from west Africa; indeed, they are sometimes considered the same species. Ogilby's duiker is darker in coloration, and has a dorsal stripe the extends onto the tail.
• The bay duiker (Cephalophus dorsalis) is nocturnal in habits, richer red in color, and has a wider dorsal stripe that extends up the neck to the back of the head.
• The white-bellied duiker (Cephalophorus leucogaster) has a very wide dorsal stripe that often has a scalloped edge. The dorsal stripe of Peters's duiker (Cephalophorus callipygus) widens towards the tail, spreading out over the hindquarters.
• The black-fronted duiker (Cephalophorus nigrifrons) and Weyns's duiker (Cephalophorus weynsi) do not possess a distinct dorsal stripe.

Nothing is known about the breeding or development of Ogilby's duiker. It has been reported that the young have speckled coats.

Ogilby's duiker is one of the least-known duikers. It is diurnal in nature, showing very little activity in the hours of darkness, but is very secretive. Foraging typically occurs in the morning and late afternoon. Ogilby's duikers may follow monkeys moving through the forest canopy in order to feed on fruits, seeds, and flowers that fall to the ground. The midday is often spent resting. The few reported observations of wild Ogilby's duikers suggest that individuals maintain small home ranges (approximately 0.1 km² in size). The same areas are returned to nightly for sleeping, and latrine spots are used. The principal vocalization is a "wheet" call.

Family group: Solitary or in pairs.

Diet: Fruits and seeds, flowers, and leaves.

Main Predators: Leopard and small cats; on Bioko, drills and pythons are the principal predators.

Ogilby's duiker inhabits primary rainforest, usually with a closed forest canopy. On Bioko Island, they may be found at elevations up to at least 2,260 m. C. o. ogilbyi is found in Nigeria, Cameroon, and Equatorial Guinea (Bioko), and C. o. crusalbum is native to Gabon and Congo. The approximate range is depicted in the map below.

IUCN Red List:Least Concern (2016)

CITES Listing: Appendix II (2024)

Threats: Habitat loss and hunting for bushmeat.

The estimated total population (from 1999) is 30,000 animals, comprised of ~12,000 Ogilby's duiker (C. o. ogilbyi) and ~18,000 white-legged duiker (C. o. crusalbum).