 Cephalophus
zebra
Zebra duiker, banded duiker |
Taxonomy | Description
| Reproduction | Ecology
| Behavior | Distribution
| Conservation | Remarks
| Literature |
| Taxonomy
-
Cephalophus zebra [Gray, 1838].
-
Citation: Ann. Nat. Hist., 1:27
-
Type locality: Sierra Leone
The taxonomic record (above) is taken from Wilson and Reeder (1993).
Invalid synonyms for C. zebra include C. doria, C.
doriae, and C. zebrata (Wilson, 1987; Wilson and Reeder, 1993;
Kingdon, 1997). This duiker is the only member of the subgenus
Cephalophula [Knottnerus-Meyer, 1907] (Nowak, 1991). C.
zebra is monotypic (Kingdon, 1997).
General Characteristics
This stocky, muscular duiker is easily distinguished from all other duikers
- and indeed all other artiodactyls - by its dramatic coloration (Kingdon,
1997). Reported adult weights range from 9-20 kg, although there is
little consensus regarding typical minimum or maximum values. Body
length is 85-90 cm, shoulder height is 40-50 cm, and the tail is approximately
15 cm in length.
Reported measurements for zebra duiker (Cephalophus zebra) |
| Source |
Adult Weight |
Head & Body Length |
Shoulder Height
|
Tail Length |
| Happold, 1973 |
9-13.5 kg |
- |
41cm |
- |
| Kingdon, 1997 |
15-20 kg |
70-90 cm |
40-50 cm |
10-15 cm |
| Schweers, 1984 |
- |
- |
40-50 cm |
- |
| Walther, 1990 |
15-20 kg |
85-90 cm |
40-50 cm |
15 cm |
| Wilson, 1987 |
9-15 kg |
85-90 cm |
- |
15 cm |
The zebra duiker has one of the most distinctive coats of any mammal and
cannot easily be confused with any other species. An array of 12-15
black stripes cross the back and travel vertically down the sides, located
from behind the shoulders all the way down to the root of the tail (Wilson,
1987; Walther, 1990; Kingdon, 1997). These transverse bands are wide
at the spine and taper as they round over the flanks such that their tips
form a lateral line between the limbs (Kingdon, 1997). As with their
namesake, the zebras, the striping pattern is unique to each zebra duiker.
In between these bold black markings, the coat is light gold, cream,
or reddish-brown in color (Schweers, 1984; Kingdon, 1997). The undersides,
including the belly, chest, and throat, are light yellow to nearly white
and lack stripes, while the head, shoulders, and lower legs are a deep russet
(Happold, 1973; Schweers, 1984; Kingdon, 1997). Dark garter-like markings
ornament the upper legs, and in the hind legs, these bands cover a tufted
gland just distal to the hocks (Kingdon, 1997). The tail is the
same rufous as the rump, but has white hairs on the underside (Happold, 1973).
The face is a deep chestnut brown color, and the muzzle is black (Kingdon,
1997). While the jowls may be slightly lighter than the face, the zebra
duiker lacks distinctive facial markings. The forehead lacks the tuft
typical of most duikers, but, along with the nasal areas of the skull, the
forehead is heavily reinforced with thick bone (Happold, 1973; Walther, 1990;
Kingdon, 1997). Both sexes grow horns, which are robust, conical, and
sharply pointed (Kingdon, 1997). Like most duikers, the horns are rather
short, growing 4-5 cm long in males and no more than 2-2.5 cm in females
(Walther, 1990).
Ontogeny and Reproduction
The duration of estrus is reported by Schweers (1984) as 0.5-1 days, and,
due to a post-partum estrus, zebra duiker females are able to conceive within
ten days after giving birth. A female studied by Schweers (1984) in
the Frankfurt Zoo had an average interbirth interval of 241 days, although
in natural conditions the difficulties of finding a mate may increase this
time.
The gestation period of C. zebra is 221-229 days, after which a single
young is born (Schweers, 1984). Several weeks prior to parturition,
a pregnant female will begin to hold her tail away from her body (Udell,
1981). The vulva becomes swollen about 2 days before parturition,
resulting in the adoption of an even more pronounced s-shaped tail posture
to reduce contact with the genital region (Schweers, 1984). During
labor, the expectant mother lays down and rises repeatedly, with the birth
usually occurring while standing (Schweers, 1984). Four out of five
births observed by Schweers (1984) occurred between 0900 and 1100
hours. Udell (1981) estimated the weight of a zebra duiker at
birth to be 1.8 kg, Barnes et al. (2002) report birth weights ranging
from 1.27-1.75 kg [with an average of 1.48 kg], and Schweers (1984) estimated
birth weights to be 1.5-1.6 kg. This is relatively heavy for larger
mammals, comprising about 10% of the maternal body weight (Schweers, 1984).
Males are slightly heavier than females at birth (Barnes et al.,
2002). Immediately after birth, the mother licks the amniotic sac off
of the youngster, and will also eat the afterbirth once it is passed , which
normally occurs away from the birth site (Schweers, 1984).
Young zebra duikers are born with a bluish cast to their coat (rather than
golden of adults), which gradually lightens and brightens beginning at two
months of age (Udell, 1981). The characteristic stripes of C.
zebra are recognizable from the outset, but are positioned much closer
together in newborns, reducing the amount of yellow visible and thus giving
the youngster an overall darker appearance (Schweers, 1984). At birth,
the head and lower legs are dark brown (Schweers, 1984). Like most
young antelope, the legs are long in proportion to the body (Schweers, 1984).
The skin of juveniles is softer than that of adults, and the sensory
hairs on the face appear longer (Schweers, 1984).
Zebra duiker calves are precocious, but act as "hiders", lying up in one
place for 2-3 weeks after being born (Udell, 1981; Schweers, 1984).
They are able to nurse shortly after birth (within 15 or 30 minutes),
and for the first few weeks will nurse about four times per day, each session
lasting several minutes (Udell, 1981; Schweers, 1984). Within 8-10
days, youngsters increase in weight to between 1.71 and 2.2 kg, and at 25-30
days may weigh 2.85-3.60 kg (Barnes et al., 2002). At 40-45
days, weights for both sexes are between 3.62-4.62 kg (Barnes et al.,
2002). Calves begin to nibble on solid food after one week,and captive
hand-reared zebra duikers have been weaned at 95 days of age (Udell, 1981;
Barnes et al., 2002). In the mother-reared duikers studied by
Schweers (1984), the last attempts at nursing occurred at approximately 120
days of age, although successful attempts had ceased a few weeks earlier.
Juveniles 7-9 months of age possess adult coloration and have reached their
adult height, but can still be differentiated from adults by their delicate
figures (Schweers, 1984). The horns begin to grow between one and two
months of age (Udell, 1981; Schweers, 1984). Males reach sexual maturity
at about 2 years of age (Barnes et al., 2002).
Ecology
C. zebra inhabits closed canopy primary forests, but is also found
along forest margins and clearings, extending into secondary growth (Kingdon,
1997; Newing, 2001). Lowland forests (especially in river valleys)
are preferred, but montane and upland forests are also colonized (Kingdon,
1997).
Breeding pairs are believed to be the normal social unit, and strong bonds
form between captive pairs, involving 'friendly' interactions such as mutual
rubbing and licking (Udell, 1981; Kingdon, 1997). In the wild, it is
likely that both sexes defend a territory against competitors, and may also
take an active role in defending their offspring (Kingdon, 1997).
Scarred heads on individuals suggest that fighting is especially vigorous
in C. zebra (Kingdon, 1997). Kingdon (1997) suggests that the
stripes on the body may serve as a focus for social interactions, reducing
the likelihood of being gored in the abdomen in vigorous aggressive encounters.
Observations of captive specimens at the Monrovia Zoo, Liberia, suggest
that C. zebra is a diurnal species, being active about 71% of the
daylight hours, and less than 10% of the night (Newing, 2001).
The zebra duiker feeds on on leaves and fruits, and does not appear to be
specialized into a specific dietary niche (Kingdon, 1997). Kingdon
(1997) suggests that C. zebra may use its forehead to crack open larger
thick-shelled fruits (Kingdon, 1997). Details on the diet of this species
are unknown. Newing (2001) reports that zebra duikers will occasionally
raid farmlands adjacent to forest to feed on crops. Individuals in
the Frankfurt Zoo ate dead mice which were provided, sometimes after an extended
period of play in which the mouse was shaken and tossed into the
air (Schweers, 1984). Captive individuals have shown an apparent
increased requirement for dietary copper as compared to conspecifics (Farst
et al., 1980).
Behavior
The following account on the breeding behavior of C. zebra is summarized
from the detailed study conducted by Schweers (1984) on captive individuals
in the Frankfurt Zoo. Males determine the reproductive status of females
by smelling urine with a characteristic flehmen response, whereby
the upper lip is curled upwards and the mouth is opened. In the days
leading up to sexual receptivity, a male may apply secretions from his antorbital
glands to the carpal and tarsal joints, head, neck, and back of the female,
a behavior also noted by Udell (1981). Although the pair of zebra duikers
observed by Schweers mutually marked each other outside of the female's
estrus period, the frequency of this behavior was much more noticeable in
the male duiker as the female approached estrus. In the wild, this
may signal to other males that the female in question is being courted by
another male.
Courtship in this species is relatively simple, with the male pursuing the
female. This driving behavior may occur even when the female is not
receptive. As the female approaches estrus, the pace with which the
male follows after the female increases, and is accompanied by the male licking
the neck, hind legs, and anogenital region of the female. Females respond
to such attention by grunting loudly, turning the head to the side and stretching
the lips to the side such that the bright lower surface of the chin becomes
visible. While being driven by the male, a female will keep her head
low and stretched forward, with the ears folded back. The male usually runs
directly behind the female, stretching his head forward such that his
neck is horizontal and the head is held at height the female's tarsal gland,
a posture also reported by Udell (1981) for this species. The pursuit
is performed with increasing frequency and urgency as the female approaches
estrus. In addition to this, as females become more receptive they
reduce the lateral swishing of the tail during pursuit and begin to hold
it away from the body.
Mounting attempts occur when the female stops during pursuit. Mounting,
preceded by the male smelling and licking the female's anogenital region,
is initiated by the male pushing his chin onto the croup of the female.
Copulation attempts are brief, lasting only a few seconds, but are
repeated frequently (see Udell, 1981). Initial mounting attempts may
occur during pursuit, with the female speeding up her pace to prevent successful
intromission. As the female becomes receptive, her pace during pursuit
slows and the number of stops increases, allowing the male increased opportunity
to mount. While following the female, the male (and sometimes the female)
makes throaty grunting sounds (also reported by Udell, 1981). Successful
breeding was not observed by Schweers (1984), who suggests that this likely
occurred at night.
Schweers (1984) recorded two ritualized behaviors performed by the male towards
a receptive female. The first was a frequent high lifting of the foreleg,
which occurred briefly before each mounting attempt. In this posture,
the front leg was aimed past the hind legs of the female, rather than in
between the legs as with the laufschlag of the gazelles. The
second behavior similarly involved lifting a front leg up, but in this position
the leg was held against the body of the female for an extended period of
time. This was never followed by copulatory advances, but usually lead
to the male tapping the female with his lips in order to reinstitute the
pursuit.
Distribution
From Sierra Leone (east of the Moa River) to the Cote d'Ivoire (west of the
Niouniourou River), commonest in central Liberia (Kingdon, 1997).
Countries: Côte d'Ivoire (Ivory Coast), Guinea, Liberia, and
Sierra Leone (IUCN, 2002).
Range Map (Redrawn from IEA, 1998)
Conservation Status
The IUCN has classified the zebra duiker as a vulnerable species (Criteria
A1c + C1) (Hilton-Taylor, 2000). The zebra duiker is on CITES
Appendix II (CITES, 2003). The total population is estimated at
28,000 individuals, spread across 30,000 km2 (East, 1999). This
species is threatened by poaching for meat and the continued destruction
of West Africa's remaining primary rainforests (East, 1999). The long-term
survival of the C. zebra is dependent on protected areas to safeguard
against habitat loss and control of hunting (East, 1999).
Remarks
In captivity, these duikers have been exhibited with a few primate species.
A group of talapoins was initially successful at the Los Angeles Zoo,
but the combination was discontinued once the primates attacked the male
in the exhibit (Udell, 1981).
The common name duiker ("DIKE-er") is Afrikaans for "diver" or "diving buck",
a reference to the species' characteristic flight into the undergrowth when
alarmed (Wilson, 1987). Kephale (Greek) the head; lophus
(Greek) a crest, referring to the tuft on the head. Zibra (Congolese
or Abyssinian) a zebra, can mean banded, striped, a reference to the prominent
black stripes on the abdomen. These stripes are very similar to those
of the now extinct thylacine or Tasmanian tiger (Thylacinus
cynocephalus).
-
-
Local names (from Happold, 1973)
-
Were [Fulani]
-
-
French
-
Céphalophe zèbre, Céphalophe rayé (Walther,
1990; Kingdon, 1997).
-
-
German
-
Zebraducker (Walther, 1990; Kingdon, 1997).
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Literature
Cited
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and husbandry of duikers at the Los Angeles Zoo. Zoo Biology; 21(2):
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of the Parties, valid from 13 February 2003. Available online at
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Specialist Group. Gland, Switzerland and Cambridge, UK: IUCN.
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Happold, D. C. D. 1973. Large Mammals of West Africa. London:
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Newing, H. 2001. Bushmeat hunting and management: implications
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Cephalophus zebra (Gray, 1838) im Vergleich zu anderen
Cephalophus-Arten [On the reproductive biology of the Banded duiker
Cephalophus zebra (Gray, 1838) in comparison with other species of
duiker]. Zeitschrift fur Saugetierekunde 49: 21-36
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Additional Resources
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Boitani, L., and S. Bartoli. 1982. Simon & Schuster's
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Davies, A.G. 1987. The Gola Forest Reserves, Sierra Leone. Wildlife conservation
and forest management. Gland, Switzerland and Cambridge, UK: IUCN.
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Eves, H. E., and M. I. Bakarr 2001. Impacts of bushmeat hunting
on wildlife populations in West Africa's Upper Guinea forest ecosystem.
In Hunting and Bushmeat Utilization in the African Rain Forest.
Washington D.C.: Conservation International.
Frädrich, H. 1964. Beobachtungen zur Kreuzung zwischen
Schwarzrückenducker, Cephalophus dorsalis Gray 1846, und Zebraducker,
Cephalophus zebra Gray 1838. Zeitschrift fur
Säugetierekunde; 29: 46-51.
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adaptive lineages in duiker antelope: Evidence from mitochondrial DNA sequences
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