Bovids V: Duikers

(Cephalophinae)

Class Mammalia

Order Artiodactyla

Suborder Ruminantia

Family Bovidae

Subfamily Cephalophinae

Thumbnail description
Timid small, tropical antelopes; females often larger than the males; coat color is usually reddish brown, but can be gray, black, or striped; most species have a tuft of hair between a pair of horns; maxillary glands used for scent marking; considered browsers; agile jumpers and hiders; reflect the primitive, ancient lifestyle of bovids

Size
Body length 22–59 in (59–145 cm); shoulder height 12–34 in (30–85 cm); 9–176 lb (6–80 kg)

Number of genera, species
2 genera; 18 species

Habitat
Dense forest, lowland or high montane forest, savanna, and open bush; closely tied to dense cover for hiding

Conservation status
Endangered: 1 species; Vulnerable: 3 species; Lower Risk/Near Threatened: 9 species; Lower Risk/Conservation Dependent: 3 species; Lower Risk/Least Concern: 2 species

Distribution
Sub-Saharan Africa

Evolution and systematics

The Cephalophinae belong to the neotragine radiation of bovids. The ancestors of these browsing antelope first appeared during the Miocene, and later invaded Africa and Asia. Although their fossil record is sparse, Cephalophinae share many similarities with early bovids.

Modern Cephalophinae include 18 species represented by two genera, Sylvicapra and Cephalophus. Sixty-five subspecies have been identified. Cephalophus can be divided into four subgenera, which can be described as the conservative dwarfs, the diverse red duiker lineage, the fiber duiker lineage, and the giant duiker species. Several researchers have argued that the conservative dwarf subgenus is, in fact, a unique genus, Philantomba.

Physical characteristics

The Cephalophinae vary considerably in size. Their body shape is consistent across species, and designed for traveling through dense vegetation. They have arched bodies, short forelegs, long hind limbs, and strong hindquarters. Females are often as much as 4% longer and may be taller than males. Cephalophinae weigh 9–176 lb (6–80 kg) and reach shoulder heights of 12–34 in (30–85 cm). Their coats are coarse and generally reddish brown, with a white underbelly. However, their coloring can range from pale gray to dark brown or black, and several species have unique coat colors and patterns. Tails may be as short as 1.5 in (4 cm) or as long as 6 in (15 cm). A hair tuft between a pair of short, ridged horns is common. Duikers have large, gash-like scent glands beneath the eye.

Distribution

Cephalophinae have a widespread distribution across sub-Saharan Africa and on the islands adjacent to these coastal regions. The areas of greatest density are in equatorial Africa within the rainforest belt that stretches from Guinea to the Democratic Republic of the Congo.

Habitat

Duikers prefer habitats of rainforest or dense bushland, although some species choose to live in swamps or mountainous regions. Urbanization has forced some populations to relocate or adapt to the local ecology. Others, more susceptible to habitat loss and ecological exploitation, have patchy distributions.

Behavior

Duikers earned their name for their tendency to flee in a series of diving jumps or to duck for cover beneath bushes and in fallen tree trunks when frightened. The name is derived from the Afrikaans word for diver. Most duiker species are nocturnal, foraging for food and surveying their territory from dusk to dawn. They remain sedentary during the daylight hours, often hidden inside hollow trees or behind fallen trunks.

In addition to being skittish, both male and female duikers are highly territorial animals. They are typically found alone, in pairs, or in pairs with one youngster, and they live in precisely defined habitats. Some species have fixed core territories with dynamic boundaries that overlap with other pairs, while others keep stricter borders. Duikers will patrol their territories alone or in pairs, and chase away any intruders. In zoos, male duikers are intolerant of other males and they fight violently if housed in the same pen. Females seem more tolerant of one another in captive settings.

Duikers mark their territorial boundaries, their mates, and their calf with olfactory cues secreted from the maxillary glands, located below the eye. Pedal glands, located within the hooves, and feces also serve as territorial scent markers. Bucks mutually mark by pressing their glands against each other prior to fighting.

Feeding ecology and diet

Cephalophinae have diverse diets and notable feeding habits, preferring the leaves, shoots, and tender branches of

trees and bushes, fruits, and seeds. As much as 90% of the animal's diet may be derived from fruits and leaves, with some seasonal variation. They can often be found grazing beneath trees on the fruits and seeds dropped by monkeys. Occasionally, they will eat insects, eggs, birds, and small mammals. Cephalophinae are known to raid plantations adjacent to forests for palm nuts, mangoes, and cocoa pods.

Cephlophinae conduct most foraging between dusk and dawn. The rainy season deposits enough moisture on the leaves of bushes and trees for the animals to meet their fluid needs.

Reproductive biology

All members of the Cephalophinae subfamily are monogamous, generally producing one litter per year. Females are sexually mature at approximately nine months of age, males between 12 and 18 months. Cephalophinae are non-seasonal breeders, but in some species such as the bush duiker (Sylvicapra grimmia), calf births may peak during the summer months. Gestation among the Cephalophinae can be as short

as four months or as long as nine months. Single births are the norm, but it is not unheard of for bush duikers to bear twins. Male duikers do not participate in rearing apart from delivering warnings about nearby predators and defending the trio's territory. Most calves are weaned from their mothers between five and nine months of age.

Conservation status

Due to their timid nature, it is difficult to estimate the population sizes of many species of Cephalophinae. Species with wide habitat ranges and those that are highly adaptable to changing ecological conditions are not threatened. However, 16 of 18 species have been placed on the IUCN Red List of Threatened Species. Most of those listed are Lower Risk, but C. adersi is Endangered and C. jentinki, C. spadix, and C. zebra are Vulnerable. Loss of habitat and bushmeat hunting continue to be the greatest threats to Cephalophinae.

Significance to humans

The Cephalophinae represent an essential source of protein and income throughout the forest regions of Central and West Africa. There is ample evidence that the current levels of hunting are unsustainable. In addition, the dwarf duikers are prized by trophy hunters, who seek to add full body mounts of the smaller animals to their collections.

Species accounts

List of Species

Maxwell's duiker

Cephalophus maxwelli

taxonomy

Cephalophus monitcola maxwelli (Smith, 1827), Sierra Leone.

other common names

French: Céphalophe de Maxwell.

physical characteristics

Once thought to be a subspecies of the blue duiker. Length 25–30 in (63–76 cm); height 14–16.5 in (35–42 cm); weight 11–22 lb (5–10 kg). Slate gray or gray-brown coat, with a pale belly, throat, and chin. Coloring is dark brown or charcoal-colored nose bridge and forehead, with striking white lines running from the eyes to the nose. Thin, fringed tail is 5–6 in (12–15 cm) long. Horns on both males and females are spike-like with ridges at the base. Only 2 in (5 cm) long, the horns are often hidden by the dark brown tuft of hair that grows between the horns.

distribution

Limited to western Africa, west of the Niger River.

habitat

Secondary forests and moist savanna.

behavior

Live in pairs in well-defined territories. Both sexes mark the boundaries of their ranges with secretions from the maxillary

glands. Bonded pairs often mark one another by rubbing their heads together.

feeding ecology and diet

Selective browser that consumes a varied diet of fruits, shrubs, and herbs. May also consume some small animals and insects.

reproductive biology

Bonded pairs mate one time per year. Gestation is approximately 120 days, and one calf is born from each mating. The number of births in a population peaks between January and March, with a second peak occurring between August and September. Young are weaned by one year.

conservation status

Lower Risk/Near Threatened.

significance to humans

Humans hunt it for the bushmeat trade, and have contributed to its population decline.

Black duiker

Cephalophus niger

taxonomy

Cephalophinus niger Gray, 1846, Ghana.

other common names

French: Céphalophus noir; German: Schwarzducker.

physical characteristics

Heavily built antelope: length 31–42 in (80–90 cm); height 18–20 in (45–55 cm); weight 33–66 lb (15–20 kg). Glossy dark brown to black coat that pales to gray around the neck and chin. Undersides are lighter in color, often with an orange patch between the forelegs. Nose bridge and forelock reddish brown. Head is slightly elongated with straight pointed horns, 3–7 in (8.5–21 cm) in males and 1–1.2 in (2.5–3 cm) in females. Tail approximately 5 in (12.5 cm).

distribution

Found throughout lower West Africa, in Benin, Ivory Coast, Ghana, Guinea, Liberia, Nigeria, Sierra Leone, and Togo. Populations once found in the Kalakpa and Shai Hill reserves in central and southeastern Ghana have disappeared.

habitat

Found on the edges of forests, secondary forests, and in bushes and thickets of lowland tropical rainforest. May also frequent riverine galleries, isolated forest patches, and semi-deciduous forests.

behavior

Seldom observed in the wild, its behavior has not been well studied. There are conflicting reports about whether it is a nocturnal or diurnal species. A solitary animal.

feeding ecology and diet

Its saw-like teeth permit it to browse many different types of vegetation. In addition to feeding on fallen fruits and on the flowers, leaves, herbs of forest trees and shrubs, it will use its teeth to strip the bark from trees. Will sometimes eat insects and small birds.

reproductive biology

Monogamous. Captive individuals indicate that the gestation period is 126 days, with an average of 7.5 months between births. Females give birth to a single offspring, which is weaned at six months.

conservation status

Listed as a Lower Risk/Near Threatened species. In 1999, approximately 100,000 black duikers remained in Africa, and the population continued to decline.

significance to humans

Hunted for the bushmeat trade.

Zebra duiker

Cephalophus zebra

taxonomy

Cephalophus zebra Gray, 1838, Sierra Leone.

other common names

English: Banded duiker, zebra antelope; French: Céphalophe zèbre; German: Zebraducker.

physical characteristics

Muscular duiker with unique coloration. Length 27.5–36 in (85–90 cm), height 16–20 in (40–50 cm), weight 33–44 lb (15–20 kg). Easily distinguished from other duikers by its vertical black banding. Between these stripes, the pelage is a light gold, off white, or auburn. The bands do not cross the pale yellow to white belly and undersides. Head, shoulders, and lower legs are a rich tan color. Long tail is approximately 6 in (15 cm). Horns are conical and pointed, and the head lacks the characteristic hair tuft.

distribution

Distribution restricted to small region in West Africa, between the Moa River of Sierra Leone to the west, and the Niouniourou River of Ivory Coast to the east, and concentrated in Liberia.

habitat

Primarily resides in lowland canopy forests, but will venture to the forest edges and into clearings, or live in montane and upland forests.

behavior

Both sexes will defend their territory and their offspring from competitors or other dangers. Captive zebra duiker show diurnal behavior.

feeding ecology and diet

Feeds on fruit and nuts, and may crack large, thick-shelled nuts with its forehead. Known to eat mice.

reproductive biology

Monogamous. Gestation is about 225 days, after which a single calf is born. Newborns have a bluish tint to their coat and do not develop adult-like coat coloring and stripes before seven months of age. Weaning occurs close to three months after birth.

conservation status

Considered to be a Vulnerable species. Only 28,000 remain and are restricted to a small geographical area of 12,000 mi² (31,000 km²).

significance to humans

Threatened by bushmeat hunters.

Ogilby's duiker

Cephalophus ogilbyi

taxonomy

Cephalophus ogilbyi (Waterhouse, 1838), Bioko, Equatorial Guinea. Three subspecies recognized.

other common names

French: Céphalophe d'Ogilby, céphalophe de Fernando Poo; German: Ogilbyducker, Fernando-Poo-Ducker; Spanish: Duiquero de Ogilby.

physical characteristics

Large crouched, slab-shaped body: length 34–46 in (85–115 cm); height 22 in (55 cm); weight 31–40 lb (14–18 kg). Coat color is golden brown to mahogany, darker on the hindquarters, and stippled with gray hairs along the back. Chest and undersides are pale brown or gray. Black stripe traces the length of the spine. Leg color can vary between regions and subspecies. Black muzzle has chestnut-colored arches over the eyes, and short curved horns.

distribution

Common on Bioko Island, particularly along the mountain slopes, but patchy elsewhere. Found in Cameroon, Congo, Ivory Coast, Equatorial Guinea, Gabon, Ghana, Guinea, Liberia, Nigeria, and Sierra Leone.

habitat

Closed canopy rainforest, and lowland forest and montane forest to altitudes of 2,400–3,600 ft (800–1,200 m) on Bioko Island, Equatorial Guinea.

behavior

Found alone or in pairs, it is presumed to be active during daylight hours.

feeding ecology and diet

The vast majority of its diet is made up of fruits, including those dropped by monkeys. Other vegetation and flowers make up the remainder of its diet.

reproductive biology

Nothing is known.

conservation status

Classified as a Lower Risk/Near Threatened species. Total population estimate is 35,000.

significance to humans

It is a pest to crop growers and a target of bushmeat hunters.

Jentink's duiker

Cephalophus jentinki

taxonomy

Cephalophus jentinki Thomas, 1892, Liberia.

other common names

French: Céphalope de Jentink; German: Jentinkducker; Spanish: Duiquero de Jentink.

physical characteristics

One of the largest of the Cephalophus: length 54 in (135 cm); height 30–33.5 in (75–80 cm); weight up to 154 lb (70 kg). Gray to gray-brown coloring with glossy black head and neck; shoulders are draped with a swath of white or gray hair that descends to the chest. Similar markings encircle the nose and lips. Large ridged horns angle backward from the ears.

distribution

Found in western Guinea, but restricted to scattered populations.

habitat

Fragmented habitats, consisting of fruiting trees and thick canopies. A group is said to be living in the forests outside of Freetown, Sierra Leone.

behavior

Limited interaction with Jentink's duiker suggests that they are nocturnal animals. Hide in hollow trees by day. Solitary, but often found in pairs.

feeding ecology and diet

Relies primarily on the tree seedlings and fruits, including kola nuts, cherry mahogany, and sand apples. Will forage in secondary

growth forests, scrub, farmlands, and plantations when fruits are scarce.

reproductive biology

Reproductive behavior is relatively unstudied. Gestation estimated at 7–8 months. Calves are born with dark brown coats that adopt the adult coloration by one year of age.

conservation status

Classified as Vulnerable. An estimated 3,500 individuals remain.

significance to humans

A pest to farmers and plantation owners, it is also a target for hunters in the bushmeat trade.

Red-flanked duiker

Cephalophus rufilatus

taxonomy

Cephalophus rufilatus Gray, 1846, Waterloo Village, Sierra Leone. Two subspecies.

other common names

French: Céphalophe à flancs roux; German: Rotflankenducker, Blaurückenducker; Spanish: Duiker de flancos rojos.

physical characteristics

Medium-sized antelope: length 24–28 in (60–70 cm); height 12–16 in (30–40 cm); weight 20–26 lb (9–12 kg). Dark gold to reddish brown coat with dark brown to black legs; bluish black band along the spine; dark nose and face, with blue-black

stripe running from the forehead to the muzzle, and a white upper lip and lower jaw. Maxillary glands.

distribution

Found in the eastern coastal forests of KwaZulu-Natal, Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Ivory Coast, Gambia, Ghana, Guinea-Bissau, Mali, Niger, Nigeria, Senegal, Sierra Leone, Sudan, and Togo.

habitat

Lives in gallery forests in West and Central Africa, in coastal forests of highly confined regions of southern Africa, along forest edges, and in woodlands.

behavior

Territorial animal that marks boundaries, young, and mate with scent cues. Emits shrill bark when alarmed.

feeding ecology and diet

Leaves make up approximately 60% of the diet, which is supplemented by twigs, flowers, and fruits. Consumes grasses and fungi in small quantities.

reproductive biology

The average gestation time is 240 days. Assumed monogamous.

conservation status

Classified as a Lower Risk/Conservation Dependent species; less threatened by habitat loss than any other species. An estimated 170,000 remain.

significance to humans

Purchased from bush meat markets in the Ivory Coast for dietary protein.

Bay duiker

Cephalophus dorsalis

taxonomy

Cephalophus dorsalis Gray, 1846, Sierra Leone. Two subspecies.

other common names

English: Black-striped duiker; French: Céphalophe à bande dorsale noire, céphalophe bai; German: Schwarzrückenducker.

physical characteristics

Medium to large duiker: length 28–40 in (70–100 cm); height 16–22 in (40–55 cm); weight 33–44 lb (15–20 kg). Has reddish brown coat, with blue or brown-gray legs and black dorsal stripe; white underside; white lips and lower chin. Smooth, short horns. Large maxillary glands.

distribution

Guinea-Bissau to the Democratic Republic of the Congo, and as far south as Angola.

habitat

Dense lowland forests of West and Central Africa.

behavior

Found alone or paired with mate or calf. Forage for food only between dusk and dawn.

feeding ecology and diet

Consumes mainly fruits, leaves, grasses, young branches and saplings, buds, and some insects and eggs. Occasionally will chase and kill small rodents, or other small animals.

reproductive biology

Monogamous. Females reach sexual maturity between nine and 12 months of age, approximately 3–6 months earlier than the male. Calves are weaned early, by five months.

conservation status

Labeled as a Lower Risk/Near Threatened species.

significance to humans

Hunted for bushmeat.

Yellow-backed duiker

Cephalophus silvicultor

taxonomy

Cephalophus silvicultor (Afzelius, 1815), Sierra Leone and the Pongas and Quia Rivers of Guinea. Two subspecies.

other common names

French: Céphalophe à dos jaune; German: Gelbrückenducker, Riesenducker.

physical characteristics

Largest of the duikers: length 46–58 in (115–145 cm); height 25–34 in (65–85 cm); weight 99–176 lb (45–80 kg). Dark brown to black coat with white or orange short tufts of hair along the back; gray muzzle and white lips, and maxillary glands. Ridged, wedge-shaped horns grow on both males and females.

distribution

Senegal to southwestern Sudan, western Uganda and Rwanda, south to Angola and Zambia, and western Kenya.

habitat

Forests with heavy undergrowth.

behavior

Territorial and aggressive; both females and males defend the defined region, which is heavily marked with scent cues. When scared, it will emit shrill bleats and grunts, and erect its stiff orange back hairs. Nocturnal.

feeding ecology and diet

Prefers local vegetation from the forest undergrowth, and also eats fruit, seeds, fungi, and grasses.

reproductive biology

Like many duikers, females reach sexual maturity 3–6 months before the male. Monogamous. Calves are weaned by five months of age.

conservation status

Listed as a Lower Risk/Near Threatened species.

significance to humans

Bushmeat hunting continues to threaten the population.

Resources

Books

Macdonald, David, ed. The Encyclopedia of Mammals. Vol. 2, Primates and Large Herbivores. New York: Facts On File, 2001.

Nowak, Ronald, M. Walker's Mammals of the World. 6th ed. Baltimore: Johns Hopkins University Press, 1999.

Walther, Fritz Rudolf. "Duikers and Dwarf Antelopes." In Grzimek's Encyclopedia of Mammals, Vol. 5, edited by Sybil P. Parker. New York: McGraw-Hill Publishing Company, 1990.

Wilson, Don E., and DeeAnn M. Reeder, eds. Mammal Species of the World: A Taxonomic and Geographic Reference. Washington, DC: Smithsonian Institution Press, 1993.

Periodicals

Barnes, R. F. W. "The Bushmeat Boom and Bust of West and Central Africa." Oryx 36, no. 3 (July 2002): 236–42.

Bowland, A. E., and M. R. Perrin. "Temporal and Spatial Patterns in Blue Duikers Philatomba monticola and Cephalophus natalensis." Journal of Zoology 23, no. 3 (November 1995): 487–498.

Freer, F. "Comparative Diet of Cephalophus callipygus and C. dorsalis, Sympatric bovids of the African Sempervivent Forest." Mammalia 53, no. 4 (1989): 563–620.

Hoffman, T., and H. Roth. "Feeding Preferences of Duiker (C. maxwelli, C. rufilatus, C. niger in Ivory Coast and Ghana." Mammalian Biology 68, no. 2 (2003): 65–77.

Matthee, C. A., and T. J. Robinson. "Cytochrome b Phylogeny of the Family Bovidae: Resolution Within the Alcelaphii, Antilopini, Neotragini, and Tragelaphini." Molecular Phylogenetics and Evolution 12, no. 1 (June 1999): 31–46.

Newing, H. "Bushmeat Hunting and Management: implications of Duiker Ecology and Interspecific Competition." Biodiversity and Conservation 10, no. 1 (June 2001): 99–118.

Schweers, S. "On the Reproductive Biology of the Banded Duiker Cephalophus zebra (Gray, 1838) in Comparison with Other Species of Cephalophus." Zeitschrift Für Saeugetierkunde 49, no. 1 (1984): 21–36.

van Vuuren, Bettine Jansen, and Terence J. Robinson. "Retrieval of Four Adaptive Lineages in Duiker Antelope: Evidence from Mitochondrial DNA Sequences and Fluorescence in situ Hybridization." Molecular Phylogenetics and Evolution 20, no. 3 (September 2001): 409–425.

Organizations

IUCN—The World Conservation Union. Rue Mauverney 28, Gland, 1196 Switzerland. Phone: +41 (22) 999 0000. Fax: +41 (22) 999 0002. E-mail: mail@hq.iucn.org Web site: <http://www.iucn.org>

Other

African Wildlife Foundation. "Duiker." [April 28, 2003]. <http:// www.awf.org/wildlives/68>.

IUCN. The IUCN Red List of Threatened Species. [April 28, 2003]. <http://www.redlist.org>.

Jentink's duiker. [April 28, 2003]. <http://www.animalinfo.org/species/artiperi/cephjent.htm>.

Hannah Hoag, MS