Duikers have a secretive nature, and this, combined with its dense, fairly inaccessible habitat, means that little is known about the behaviour of the yellow-backed duiker (4). It is thought to be mainly solitary, living in spaced out territories, but it is not clear whether monogamous pairs share a territory or not (2) (4). With a tendency to spend the day in dense forest, often resting under a fallen tree or amongst thick vegetation, only under the protection of darkness does the yellow-backed duiker venture out into more open areas (4). If the yellow-backed duiker does come across any danger, such as a predator, it will freeze immediately and the hairs in the yellow patch may erect; possibly as a clear, visual, alarm signal to other yellow-backed duikers (4). The yellow-backed duiker feeds on a wide range of vegetation, including fruits, leaves, shoots, seeds, bark and buds, and it may also occasionally eat carrion; in captivity a yellow-backed duiker was observed capturing, killing and eating a pigeon (4). Yellow-backed duikers are believed to give birth to one calf a year after a gestation period of 151 days. The newborn lies up in vegetation for a week or so, but begins eating solid food very quickly (2), and is fully weaned by four to six weeks of age. The horns and characteristic yellow rump are not apparent at birth, but develop over the next nine to ten months (4).

The yellow-backed duiker is the largest of all duikers; a group of animals which get their name from the Afrikaans word for 'diver', referring to their habit of diving into dense vegetation for cover. As well as its larger size, the yellow-backed duiker is distinct from other duikers due to the patch of yellow hairs on its rump, which is conspicuous against the rest of its blackish-brown coat. The body of the yellow-backed duiker is higher at the rump than at the shoulders (4), and the head is long and wedge-shaped (2). Both sexes bear short, cylindrical horns which are ribbed at the base, and a crest of longer, dull chestnut hairs sits between the horns (4).

The Yellow-backed Duiker has the widest distribution of the forest duikers, ranging from south-western Senegal through all West African countries to south-western Sudan and south-west Uganda, south to northern Angola (including Cabinda) and Zambia; they also occur in the Mau forest in south-west Kenya (Kingdon and Lahm in press). They are now considered extinct in The Gambia (East 1999), although whether they actually ever formerly occurred is uncertain (Grubb et al. 1998). They were thought to have been extirpated from Rwanda (East 1999), but have been confirmed as surviving in the Nyungwe Forest (F. Mulindahabi and A. Vedder pers. comm.).

Cephalophus silvicultor is found throughout western central Africa. Yellow-backed duikers range from Guinea-Bissau eastward to Uganda and Sudan, and as far south as Angola and Zambia. Yellow-backed duikers have the widest range in comparison to other forest duiker species. They are typically found in forested areas with dense understory growth.

Biogeographic Regions: ethiopian (Native )

The yellow-backed duiker has a wide distribution over west and central Africa, from Senegal to Zambia, but is uncommon and localised within this vast area (5).

The coat of yellow-backed duikers is black or brown in color with a yellow triangular patch near the tail. This yellow patch typically will not appear until about 1 month of age and will not be completely developed until about 10 months.  Males and females resemble each other in appearance, although females are slightly larger. The muzzle area is a light gray color which surrounds their white lips. Both sexes have short, conical horns that grow between 8.5 and 21 centimeters long.

Young yellow-backed duikers are born a dark brown color with spotted flanks and red undersides. These cryptic colors help them remain hidden from predators in the forest.

Yellow-backed duikers have unique scent glands located posterior to each eye. Unlike other antelope species, these glands secrete from a grouping of pores, not from a solitary large opening. These scent glands are used to mark territorial boundaries.  Yellow-backed duikers are built for life in dense vegetation. The body is arched, with short forelegs and longer hindlegs for manuverability.

Yellow-backed duikers are one of the largest species of forest duikers, ranging from 45 to 80 kilograms in the wild. The body is 115 to 145 centimeters in length, with a short tail measuring 11 to 18 centimeters. Yellow-backed duikers have the largest brain size relative to body size than any other antelope species.

Range mass: 45 to 80 kg.

Range length: 115 to 145 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger; ornamentation

Habitat and Ecology

Systems

• Terrestrial

Yellow-backed duikers prefer forested habitats with dense undergrowth, although they can be found in a variety of forested habitats, including savannah and farmland. There is evidence of interspecific competition between yellow-backed duikers and their larger relatives, Jentink's duikers (Cephalophus jentinki). In some situations, Jentink's duikers may force yellow-backed duikers out of preferred habitat.

In captivity, yellow-backed duikers are not tolerant of cold temperatures. They cannot be exposed to climates of 7 degrees Celsius (55 degrees Fahrenheit) for a prolonged time, but can tolerate temperatures of 43 degrees Celsius (110 degrees Fahrenheit).

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest

Other Habitat Features: agricultural

Inhabits virtually all tropical forest types, including lowland and montane forests, forest-savanna mosaics and riverine forests (4) (5).

Yellow-backed duikers are selective-foraging frugivores. Typical diets are low in fiber. Starches are fermented quickly, with rapid passage through the digestive tract. Along with fruit, yellow-backed duikers eat leaves, seeds, buds, bark, and shoots. Four yellow-backed duikers in the wild ate 71.3% fruit matter and 28.6% dry weight. Occasionally, these forest antelopes will kill and eat small animals, such as birds. Of the 28.6% dry weight, 0.1% was animal matter.

Yellow-backed duikers specialize on eating fallen fruits and can consume fruits or seeds that are too large or hard for primates and other frugivores to eat. Duiker cheek teeth are specialized for chewing tough bark and roots. A long pointed tongue and mobile lips allow foliage to be easily obtained and manipulated. Duikers search the ground for food using their hooves and snouts to dig. The large size of yellow-backed duikers forces them to forage almost constantly.

Animal Foods: birds; mammals

Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts; fruit

Primary Diet: herbivore (Frugivore )

It is unknown how important forest duikers are in seed dispersal in African forests. Duikers have been observed spitting out digested seeds after rumination. Some seeds remain intact and are dispersed in this way. Duikers act as predators on other seeds by damaging them during digestion. Larger mammals also prey on adult and young duikers.

Three new species of Coccidia have been found in forest duikers. These parasites were not found in any other wild or domestic African ruminant. Coccidia was documented in Philantomba monticola, Cephalophus dorsalis, and Cephalophus nigrifrons. Cephalophus maxwelli was discovered with the parasite Selenomas ruminanticum. It is possible that Coccidia species will be discovered in C. silvicultor.

Ecosystem Impact: disperses seeds

Predators of yellow-back duikers include African hunting dogs, lions, and leopards. When they are alarmed, the typical resopnse is for the yellow rump hairs to stand erect. A shrill call may be emitted before dashing into the cover of underbrush habitat. Young duikers stay hidden in the forest for more than 7 days to evade predators before beginning to venture out. When threatened, the response is to flee into dense forest. Their habit of seeming to dive into the undergrowth gives them their common name, duiker, which is derived from Afrikaans for "diving buck." Yellow-backed duikers also hold their yellow rump hairs erect when agitated.

Known Predators:

• lions (Panthera leo)
• African wild dogs (Lycaon pictus)
• leopards (Panthera pardus)
• ball pythons (Python regius)
• African civets (Civettictis civetta)
• crocodiles (Crocodilus)

Anti-predator Adaptations: cryptic

Yellow-backed duikers communicate with unique scent glands anterior to the eyes. These maxillary glands are made of connective tissues that surrounds 2 to 3 secretory layers forming hairless slits. The presence of these glands cause the cheeks to swell. Duikers also have scent glands behind each hoof. Gland scents are used to communicate territorial boundaries, reproductive status, and as a way of cementing social bonds. Yellow-backed duikers also communicate through grunts and shrill bleats. When alarmed, these duikers emit a shrill whistle, erect their dorsal crest, and flee.

Communication Channels: visual ; acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

In captivity, other species of Cephalophus can live 10 to 15 years. In the wild duikers can live 10 to 12 years.

Range lifespan

Status: wild: 10 to 12 years.

Average lifespan

Status: captivity: 22.5 years.

Maximum longevity: 22.5 years (captivity) Observations: One captive specimen was still alive after 22.5 years (Richard Weigl 2005).

Yellow-backed duiker mating pairs have been observed licking and nibbling each other socially. This behavior is also viewed between mothers and calves. Adult duikers socially rub their preorbital scent glands on other adults bodies and legs. Duiker mates also press these scent glands together as a possible sign of pair bonding. It is thought that females defend territories that they share with males. However, the pair bond may be fairly transitory.

Mating System: monogamous

In captivity, yellow-backed duikers go into estrus once per month throughout the year, lasting 2 to 3 days. Gestation is approximately 7 months, after which females give birth to one calf. Occasionaly, 2 calves are born. Females may breed twice each year. Young yellow-backed duikers stay hidden for 1 to 2 weeks in the forest. One male calf in captivity at the Los Angeles Zoo was weaned after 95 days, although others have been recorded at about 5 months. Females are sexually mature at 9 to 12 months of age, while males reach maturity at 12 to 18 months.

Breeding interval: Yellow-backed duikers may breed twice each year.

Breeding season: Yellow-backed duikers can breed throughout the year.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Range gestation period: 4 (low) months.

Average gestation period: 7 months.

Range weaning age: 3.17 to 5 months.

Range age at sexual or reproductive maturity (female): 9 to 12 months.

Range age at sexual or reproductive maturity (male): 12 to 18 months.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Average birth mass: 2400 g.

Average number of offspring: 1.

Young are weaned after approximately 5 months. It is unknown how long young stay with the mother. The young remain hidden for their first week of life, after which they begin to emerge from hiding to browse on vegetation.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female); extended period of juvenile learning

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 2
Species With Barcodes: 1

Human expansion has caused a change in some African habitats from mature forests to clearings for agriculture, directly impacting yellow-duiler populations, which rely on forested habitat. Yellow-backed duikers require dense forest cover to hide, because of their large size. Smaller duikers, such as blue duikers (Philantomba monticola), can conceal themselves in the more open habitats where they live.

US Federal List: no special status

CITES: appendix ii

IUCN Red List of Threatened Species: least concern

Classified as Least Concern on the IUCN Red List (1), and listed on Appendix II of CITES (3).

Population

Population Trend

Major Threats

The destruction of forests and uncontrolled hunting for food has greatly impacted the yellow-backed duiker; this species is now extinct in Gambia and possibly Rwanda, and remaining populations are declining, except for those where there is effective protection against poaching or human populations are very low (5). If this trend continues, the yellow-backed duiker is likely to become threatened with extinction (5).

Conservation Actions

The yellow-backed duiker is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this species should be carefully monitored (3). It is also likely to occur in a number of protected areas throughout its wide range, such as Outamba-Kilimi National Park, Sierra Leone (6). Whether these are sufficient measures to protect the yellow-backed duiker from becoming at risk of extinction is not clear; the destruction of central Africa's forests and uncontrolled bushmeat hunting are complex problems that require a wide array of actions to save those species affected.

There are no known adverse effects of Cephalophus silvicultor on humans.

Cephalophus silvicultor is an important form of meat and money for people living in central and western Africa. In many instances, yellow-backed duiker meat is necessary bushmeat for local survival. They are hunted with a variety of methods, including snares, shotguns, or netting. At night, duikers are easily shot because they stand still when light is shone on them.

Positive Impacts: food ; body parts are source of valuable material