Cephalophus jentinki [Thomas, 1892].

Citation:Proc. Zool. Soc. Lond., 1892:417.

Type locality:Liberia.

The taxonomic record (above) is taken from Wilson and Reeder (1993). Jentink's duiker belongs to the subgenus Cephalophus [Hamilton-Smith, 1827], which contains the "giant" duikers (Cephalophus jentinki, C. silvicultor, and C. spadix) along with the bay duiker (C. dorsalis) (Nowak, 1991; van Vuuren and Robinson, 2001). Jentink's duiker consistently clusters at the base of this family group, despite being more similar in form to the other giant duikers than the bay duiker (van Vuuren and Robinson, 2001). Despite its distinctive coloration, the skull of Jentink's duiker is so similar to that of the yellow-backed duiker (C. silvicultor) that the first (skull) specimen of the former was identified as the latter. There are no known subspecies (Wilson and Reeder, 1993).

Jentink's duiker is one of the largest duiker species; Wilson (2001) argues that it Jentink's duiker is larger and heaver than the yellow-backed duiker (C. silvicultor). This species has the robust and relatively short-legged form typical of this group (Davies and Birkenhäger, 1990; Kingdon, 1997). Average body weight is approximately 72 kg - nearly ten times that of the smallest member of the subfamily Cephalophinae, the blue duiker (Philantomba monticola) (Wilson, 2001). Body length is about 135 cm, shoulder height 80 cm, and tail length 15 cm (Walther, 1990).

This large, heavily-built duiker is strikingly particolored, with dark forequarters and pale hindquarters - a distinctive pattern also seen in the Asian tapir (Tapirus indicus) (Walther, 1990; Kingdon, 1997). The head, neck, and throat are covered in fine, smooth glossy black or brownish-black hair, while the back and rump have coarser grizzled gray-brown or "gray agouti" pelage (Happold, 1973; Kingdon, 1997, Wilson, 2001). The black and gray areas are separated by a thin band of whitish hair that encircles the shoulders and lower chest; this pale coloration encompasses the front legs and is also present on the hind legs (Happold, 1973; Kingdon, 1997). There is no dorsal stripe (Happold, 1973). The tail is remarkably thin, and is the same grizzled gray as the hindquarters (Davies and Birkenhäger, 1990).

The deep eye-sockets and large slit-like openings of the preorbital glands are the most conspicuous features of the face; facial markings are limited to a whitish halo that surrounds the nose and lips (Happold, 1973; Kingdon, 1997). Unlike many other duiker species, there is no tuft of hair on the forehead, nor are there red-brown hairs between the horns as seen in other dark duikers (Happold, 1973; Davies and Birkenhäger, 1990). Both sexes have a pair of dark, spike-like horns (Walther, 1990). The horns are large compared to other duikers and extend backwards from head, curving slightly downward towards the tips (Happold, 1973; Davies and Birkenhäger, 1990). Horn lengths are typically given as being from 15.5 cm to 17.5 cm (see Walther, 1990). However, four individuals from Sierra Leone measured by Wilson and Wilson (1990) had horn length ranging from 14.4 to 21.2 cm. One pair of horns examined by Davies and Birkenhäger (1990) each measured 21.5 cm in length, had a basal circumference of 9.5 cm, and were entire smooth with the exception of the lower 3.5 cm which were conspicuously ridged.

Virtually nothing is known of the reproductive habits of Jentink's duiker in the wild. In captivity, males may occasionally puncture the perineal or tailhead region of the female during courtship, although these wounds heal readily (Farst et al., 1980). The gestation period is likely similar to that of the yellow-backed duiker (Cephalophus silvicultor), approximately 8 months. Neonates weigh 3.3-5.9 kg, and are born entirely dark brown, with white markings around the lips (Wilson, 2001). The change to the distinctive adult coat occurs around one year of age (Walther, 1990; Wilson, 2001). Juvenile Jentink's duikers resemble young yellow-backed duikers - so much so that a young wild-caught individual was misidentified as the latter until its adult coloration was acheived (Wilson and Wilson, 1990). Several captive specimens have lived into their mid-teens; the longevity record is 21 years (Weigl, 2005).

Comparatively little is known about C. jentinki, due to the inaccessibility of its habitat, its rarity, and its secretive nature. The basic habitat requirements for Jentink's duiker appear to be a diversity of fruiting trees and very dense shelter (Happold, 1973; Kingdon, 1997). Most observations of this species occur in high closed-canopy forest (Newing, 2001; Wilson, 2001), although this species is also seen in secondary forest and farmbush. Due to human encroachment on forested land, much of the habitat remaining for this duiker species is fragmented and restricted to areas inaccessible to most human activity (Davies and Birkenhäger, 1990).

Jentink's duikers are known to be preyed upon by leopards (Panthera pardus) (Wilson, 2001); other predatory species like large pythons probably also hunt this species.

No feeding studies have yet been performed on wild Jentink's duikers. Growing stems of tree seedlings are reported as a primary food source, with Hannoa klaineana and Chlorophora regia being specifically mentioned by hunters (Davies and Birkenhäger, 1990; Kingdon, 1997). When available, Jentink's duikers will feed on hard-shelled fruits such as kola nuts and the fruits of erimado (Ricinodendron), cherry mahogany (Tieghemella), sand apples (Parinari) and tallow trees (Pentadesma) (Kingdon, 1997). Jentink's duikers will also enter plantations to feed on palm nuts, mango, and cocoa pods (Kingdon, 1997). This species has also been reported chewing on roots after digging them up with their hooves (Kingdon, 1997). While specific dietary requirements are not known, wild Jentink's duikers are known to visit the sea shore - where their tracks are seen on the beach - to lick salt from the sand (Wilson and Wilson, 1990; Kingdon, 1997).

Evidence points to C. jentinki being largely nocturnal (Kingdon, 1997). This species is typically hunted at night, when hunters can use torches to pick up the eye-shine of the animals (Wilson and Wilson, 1990; Newing, 2001). A captive specimen observed by Newing (2001) at the Monrovia Zoo was active for 28 % of the daylight hours (06:30-18:00) and 40% of the night-time hours (18:30-06:00). During the day, Jentink's duikers use hollow trees, fallen trunks, and buttress bays of kapok (Ceiba pentandra), Bombax, and mututu trees (Klainedoxa gabonensis) for shelter (Kingdon, 1997). If discovered in their hiding spot, a Jentink's duiker will bolt from its refuge at great speed, but due to poor stamina can not go far (Kingdon, 1997).

During periods when fruits are scarce, this species may enter secondary growth forest, scrub, farms, and plantations to feed at night (Kingdon, 1997). This apparently occurs frequently during rainy season in Sierra Leone, from May to October, when C. jentinki reportedly descends from upland forests to feed in coastal farmlands (Davies and Birkenhäger, 1990). The majority of observations of Jentink's duikers in the wild are of solitary individuals, although pairs are occasionally seen (Kingdon 1997; Wilson, 2001). This species appears to be sedentary and is supposedly territorial (Kingdon, 1997).

Jentink's duiker is endemic to the western Guinean forest block, restricted to the east by the Niouniourou River (Davies and Birkenhäger, 1990; Kingdon, 1997). Due to habitat destruction, C. jentinki is now restricted to scattered pockets of remaining forests in the southern tip of West Africa.

Countries: Côte d'Ivoire, Liberia, Sierra Leone (IUCN SSC Antelope Specialist Group, 2008).

Jentink's duiker is classified as endangered by the IUCN (2008), and is on CITES Appendix 1 (CITES, 2011). The major threats to the persistence of this species are habitat loss (primarily from extraction of timber) and harvesting for food (IUCN SSC Antelope Specialist Group, 2008). Based on avialble habitat, East (1999) estimated there to be perhaps 3,500 individuals in the wild, although Wilson (2001) suggests that the actual figure may be no more than 2,000.

After its formal description and the discovery of three specimens, Jentink's duiker virtually disappeared - no sightings (either real or unconfirmed) were reported for over 50 years (Shuker, 1993). This was especially troubling, as this is an antelope not to be overlooked or confused with another species. However, in 1948, a skull of an adult male was obtained in Côte d'Ivoire, and since then many specimens have been observed (Shuker, 1993).

The scientific name Cephalophus jentinki is derived from kephale (Greek) the head and lophus (Greek) a crest, referring to the tuft on the head found in many members of this genus. F. A. Jentink described the first specimen, a female, collected by F. X. Stampfli in 1884 - although it was misidentified as a form of yellow-backed duiker ("Cephalophus longiceps" from Gabon) (Wilson, 2001). Duiker ("DIKE-er") is Afrikaans for "diver", due to their habit of bounding into the undergrowth when alarmed.

Local names

Gidi-gidi, Gri-gri [Krio] (Davies and Birkenhäger, 1990)

Kaikulowuli, Kaikulowulei [Mende tribal name meaning "squirrel duiker"] (Wilson and Wilson, 1990)

Dikidiki [Creole] (Wilson and Wilson, 1990)

Nienagbé [from Côte d'Ivoire](Shuker, 1993)

Nyonoploo-Nynabeh [Sapo] (Wilson, 2001)

 

French

Céphalophe de Jentink (Happold, 1973)

 

German

Jentinks Ducker (Happold, 1973)

 

Spanish

Duiquero de Jentink (IUCN SSC Antelope Specialist Group, 2008)