 Cephalophus
jentinki
Jentink's duiker |
Taxonomy | Description
| Reproduction | Ecology
| Behavior | Distribution
| Conservation | Remarks
| Literature |
| Taxonomy
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Cephalophus jentinki [Thomas, 1892].
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Citation: Proc. Zool. Soc. Lond., 1892:417
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Type locality: Liberia.
The taxonomic record (above) is taken from Wilson and Reeder (1993).
C. jentinki is included in the subgenus Cephalophus
[Hamilton-Smith, 1827], which contains the three "giant duiker" species (C.
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). There are no known subspecies,
and (being such a distinctive species), it is no surprise that there
are no synonyms (Wilson and Reeder, 1993).
General Characteristics
Jentink's duiker is one of the largest members of the genus
Cephalophus (Davies and Birkenhäger, 1990). Average body
weight is around 70 kg - nearly ten times that of the smallest member of
the subfamily Cephalophinae, the blue
duiker (Philantomba monticola) (Walther, 1990). Body length
is about 135 cm, shoulder height 80 cm, and tail length 15 cm (Walther, 1990).
Reported measurements for Jentink's duiker (Cephalophus
jentinki) |
| Source |
Adult Weight |
Head & Body Length |
Shoulder Height
|
Tail Length |
| Happold, 1973 |
64 kg |
- |
79 cm |
- |
| Kingdon, 1997 |
55-80 kg est. |
130-150 cm est. |
75-100 cm est. |
12-16 cm est. |
| Walther, 1990 |
70 kg |
135 cm |
75-80 cm |
15 cm |
| Wilson, 1987 |
- |
135 cm |
- |
15 cm |
The body form of C. jentinki is typical of the duikers, being robust
and relatively short-legged (Kingdon, 1997). This large, heavily-built
duiker is difficult to confuse with any other ungulate due to its striking
coloration (Happold, 1973). Similar to
Malayan tapir (Tapirus
indicus), Jentink's duiker has dark forequarters and light hindquarters,
with the coloring involving both skin and fur pigments (Walther, 1990; Kingdon,
1997). Across the body the pelage is very short and fine (Kingdon,
1997). The head, neck, and throat are a dark, glossy black or
brownish-black, which contrasts with a thin collar or halter of white or
light grey hair which runs over the shoulders and lower chest, just
in front of the front legs (Happold, 1973; Kingdon, 1997). The back
and rump are a grizzled grey-brown or "grey agouti" (Happold, 1973; Kingdon,
1997). There is no dorsal stripe as seen in many other duiker species
(Happold, 1973). All four legs are the same light grey color as the
collar (Happold, 1973). The tail is remarkably thin, and is the same
grizzled gray as the hindquarters (Davies and Birkenhäger, 1990).
Facial markings are limited to the muzzle area, where a white-gray halo surrounds
the nose and lips (Happold, 1973; Kingdon, 1997). Unlike many other
duiker species, there is no evidence of a 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). The skull is
structurally similar to that of the bay duiker (Cephalophus dorsalis)
(Kuhn, 1968 in Newing, 2001).
The horns are borne by both sexes of this species (Walther, 1990).
Straight and smooth, but curving slightly downward towards the tips,
the horns are large compared to other duikers and extend backwards from head
in the plane of the face (Happold, 1973; Davies and Birkenhäger, 1990).
The horns are black in color, are rather narrow, and have an oval cross
section (Davies and Birkenhäger, 1990). Horn lengths are
typically given as being from 15.5 cm to 17.5 cm (Walther,
1990). However, on examining horns from four individuals from
Sierra Leone, Wilson and Wilson (1990) found lengths 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.
Ontogeny and Reproduction
When attempting to mate, males may occasionally puncture the perineal or
tailhead region of the female, although these wounds heal readily (Farst
et al., 1980). The gestation period is not known, but is likely
similar to that of the yellow-backed
duiker (Cephalophus silvicultor). Juvenile Jentink's duikers
resemble young yellow-backed duikers - so much so that there is one instance
where a young wild-caught individual being handraised was misidentified,
with the true identity not becoming apparent until it had grown up (Wilson
and Wilson, 1990). Young are born dark brown all over and have white
markings around their lips (Walther, 1990). Adult coloration is obtained
at approximately one year of age (Walther, 1990). A captive individual
at the Gladys Porter Zoo (Brownsville, Texas) lived for approximately 21
years, and several other captives have lived into their mid-teens (ISIS,
2003).
Ecology and Behavior
Cephalophus jentinki is a poorly studied species, due in part to the
inaccessibility of its habitat and confounded by its secretive nature (Kingdon,
1997). The basic habitat requirements for Jentink's duiker appear to
be a diversity of fruiting trees and very dense shelter (Happold, 1973; Kingdon,
1997). Newing (2001) observed Jentink's duikers in closed canopy forests,
and never in secondary vegetation. 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).
Although the habits of this species have not been studied, evidence points
to C. jentinki being largely nocturnal (Kingdon, 1997). Most
specimens which have been collected were shot at night, when hunters can
use torches to pick up the eye-shine of the animals (Wilson and Wilson,
1990; Newing, 2001). During periods when fruits are scarce, Jentink's
duikers may make nocturnal forays out of the forest, entering secondary growth
forest, scrub, farms, and plantations (Kingdon, 1997). This apparently
occurs frequently during rainy season in Sierra Leone, from May to October,
when C. jentinki descends from upland forests at night to feed in
coastal farmlands, much to the chagrin of the farmers (Davies and
Birkenhäger, 1990). A captive specimen observed by Newing
(2001) at the Monrovia Zoo was active for 28 % of the daylight hours (0630-1800
hours) and 40% of the night-time hours (1830-0600 hours). During the
day, Jentink's duikers use hollow trees, fallen trunks, and buttress bays
of kapok (Ceiba), Bombax, and mututu trees (Klainedoxa)
for shelter (Kingdon, 1997). Kingdon (1997) reports that C.
jentinki sometimes lies up in pairs, a feature unusual for typically
solitary duikers (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). This species appears to be
sedentary and is supposedly territorial (Kingdon, 1997).
Growing stems of tree seedlings are a primary food source for C.
jentinki, with species being browsed most frequently including Hannoa
klaineana and Chlorophora regia (Davies and Birkenhäger,
1990; Kingdon, 1997). When available, this species will feed on fruits,
many of which have hard shells (Kingdon, 1997). Fruits eaten include
kola nuts, 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 for C. jentinki 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).
Distribution
Jentink's duiker is endemic to the western part of the Guinean forest block,
located between Sierra Leone and the River Niouniourou (Davies and
Birkenhäger, 1990; Kingdon, 1997). This distribution is very similar
to that of the zebra duiker (Cephalophus
zebra) and several primate species (Kingdon, 1997). Due to
habitat destruction, C. jentinki is now restricted to scattered localities
in forests in the southern tip of West Africa (Happold, 1973).
Countries: Côte d'Ivoire (Ivory Coast), Liberia, Sierra Leone
(IUCN, 2002).
Range Map (Compiled from Kingdon, 1997; IEA, 1998)
Conservation Status
Jentink's duiker is classified as vulnerable [A1c, C1] by the IUCN (2002),
and is on CITES Appendix 1 (CITES, 2000). The major threats to the
persistence of this species are habitat loss - primarily through extraction
of timber - and harvesting for food (IUCN, 2002). The wild population
is estimated at 3,500 individuals (East, 1999).
Remarks
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).
Kephale (Greek) the head; lophus (Greek) a crest, referring
to the tuft on the head found in many members of this genus. F. A.
Jentink collected the first specimen, a female, while working for F.
X. Stampfli in 1884.
Duiker ("DIKE-er") is Afrikaans for "diver", due to their habit of bounding
into the undergrowth when alarmed.
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Local names (from Davies and Birkenhäger, 1990; Wilson and Wilson,
1990; Shuker, 1993)
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Gidi-gidi, Gri-gri [Krio]
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Kaikulowuli, Kaikulowulei [Mende tribal name meaning "squirrel
duiker"]
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Dikidiki [Creole]
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Nienagbé [from Côte d'Ivoire]
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French
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Céphalophe de Jentink (Happold, 1973)
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German
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Jentinks Ducker (Happold, 1973)
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Spanish
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Duiquero de Jentink (IUCN, 2002)
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Literature
Cited
CITES (Convention on the International Trade in Endangered Species of Wild
Flora and Fauna). 2000. Appendix 1, as adopted by the Conference
of the Parties, valid from 19 July 2000. Available online at
http://www.cites.org/eng/append/I_II.shtml
Davies, G., and B. Birkenhäger (1990). Jentink's duiker in
Sierra Leone: Evidence from the Freetown Peninsula. Oryx, 24(3): 143-146
East, R. [compiler]. 1999. African Antelope Database 1998. IUCN/SSC Antelope
Specialist Group. Gland, Switzerland and Cambridge, UK: IUCN.
Farst, D. D., D. P. Thompson, G. A. Stones, P. M. Burchfield, and M. L. Hughes.
1980. Maintenance and breeding of duikers (Cephalophus
spp.) at Gladys Porter Zoo, Brownsville. International Zoo Yearbook
20: 93-99.
Happold, D. C. D. 1973. Large Mammals of West Africa. London:
Longman Group, Ltd.
IEA (Institute of Applied Ecology) 1998. Cephalophus jentinki.
In African Mammals Databank - A Databank for the Conservation
and Management of the African Mammals Vol 1 and 2. Bruxelles: European
Commission Directorate. Available online at
http://gorilla.bio.uniroma1.it/amd/amd154b.html
ISIS (International Species Information System). 2003 Specimen
Records.
IUCN (International Union for Conservation of Nature and Natural Resources).
2002. 2002 IUCN Red List of Threatened Species. Available
online at http://www.redlist.org/
Kingdon, J. 1997. The Kingdon Field Guide to African Mammals. Academic
Press, London and New York: NaturalWorld.
Newing, H. 2001. Bushmeat hunting and management: implications
on duiker ecology and interspecific competition. Biodiversity and
Conservation 10(1): 99-108.
Nowak, R. M. [editor]. 1991. Walker's Mammals of the World (Fifth Edition).
Baltimore: The Johns Hopkins University Press.
Shuker, K. 1993. The Lost Ark: new and rediscovered animals of
the Twentieth Century. London: HarperCollinsPublishers.
van Vuuren, B. J., and T. J. Robinson. 2001. Retrieval of four
adaptive lineages in duiker antelope: Evidence from mitochondrial DNA sequences
and fluorescence in situ hybridization. Molecular Phylogenetics and
Evolution 20(3): 409-425.
Walther, F. R. 1990. Duikers and Dwarf Antelopes.
In Grzimek's Encyclopedia of Mammals, Volume 5. Edited
by S. P. Parker. New York: McGraw-Hill. pp. 325-343.
Wilson, D. E., and D. M. Reeder [editors]. 1993. Mammal Species of the World
(Second Edition). Washington: Smithsonian Institution Press.
Available online at
http://nmnhwww.si.edu/msw/
Wilson, V. J. [compiler] 1987. Action plan for duiker conservation -
IUCN/SSC Antelope Specialist Group and Chipangali Wildlife Trust.
Wilson, V. J., and B. L. P. Wilson. 1990. Notes on the duikers
of Sierra Leone. Arnoldia-Zimbabwe; 9(33): 451-462.
Additional Resources
Barnes, R., K. Greene, J. Holland, and M. Lamm. 2002. Management
and husbandry of duikers at the Los Angeles Zoo. Zoo-Biology 21(2):
107-121.
Eves, H. 2000. Duikers: A primary target for Africa's bushmeat trade.
Animal Keepers' Forum 27(11): 497-505.
Kuhn, H. J. 1968. Der Jentink-Ducker. Natur und Museum 98(1):17-23.
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