 Raphicerus
campestris
Steenbok |
Taxonomy | Description
| Reproduction | Ecology
| Behavior | Distribution
| Conservation | Remarks
| Literature |
| Taxonomy
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Raphicerus campestris [Thunberg, 1811].
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Citation: Mem. Acad. Imp. Sci. St. Petersbourg, 3:313.
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Type locality: South Africa, Cape of Good Hope.
The initial taxonomic record (above) is provided by Wilson and Reeder (1993).
Over 24 subspecies of the steenbok have been named, although their
validity is questionable. Two generally accepted, broad subspecies
groups are R. c. campestris from southern Africa and R. c.
neumanni from east Africa (Kingdon, 1997). Invalid synonyms for
Raphicerus campestris include acuticornis, bourquii, capensis,
capricornis, cunenensis, fulvorubescens, grayi, hoamibensis, horstockii,
ibex, kelleni, natalensis, neumanni, pallida, pediotragus, rupestris,
steinhardti, stigmatus, subulata, tragulus, ugabensis, zukowskyi,
and zuluensis (Wilson and Reeder, 1993).
General Characteristics
A member of the dwarf antelope group, steenbok are petite, weighing 7-16
kg and measuring 70-95 cm in length. Unlike the crouched stance of
forest duikers, steenbok carry their head high and have long legs, with a
shoulder height between 45 and 60 cm.
Reported measurements for steenbok (Raphicerus campestris) |
| Source |
Adult Weight |
Head & Body Length |
Shoulder Height
|
Tail Length |
| Kingdon, 1997 |
7-16 kg |
70-95 cm |
45-60 cm |
4-6 cm |
Nowak, 1991
For Raphicerus |
7-16 kg |
61-95 cm |
45-60 cm |
4-8 cm |
| Walther, 1990 |
10-16 kg |
70-90 cm |
45-60 cm |
5-10 cm |
Steenbok have rather coarse pale brown hair, with regional variation from
fawn to bright rufous or even gray over the upper parts (Nowak, 1991; Kingdon,
1997). The underside of the body, including the insides of the legs
and underside of the tail is white (Nowak, 1991). The pelage is very
uniform in color, with a crisp interface between the brown upper body and
white underparts. The haunches of the steenbok are rounded, although
the back is relatively flat (Kingdon, 1997). The tail is short and
thin, but according to Kingdon (1997) it is not readily visible. The
general size, shape, and coloration of the steenbok is similar to the gray
duiker (Sylvicapra grimmia) and oribi (Ourebia ourebi), and
this antelope may be mistaken for either species in the field (Kingdon, 1997).
There are no dewclaws present (Nowak, 1991).
Steenbok are renowned for their very large ears, which are covered with white
hair on their inside surface (Kingdon, 1997). A black "V"-shaped wedge
on the bridge of the nose constitutes the only major facial marking (Walther,
1990; Kingdon, 1997). The small nose is slightly upturned and naked
at the tip (Walther, 1990; Kingdon, 1997). Small preorbital glands
are present just in front of the large dark eyes (Walther, 1990; Kingdon,
1997). The eyes themselves are rimmed with black skin, and then surrounded
by a ring of white hair (Kingdon, 1997).
Males possess a pair of very upright horns - these are never found in
females (Walther, 1990; Kingdon, 1997). The horns are simple spikes
which are entirely smooth, lacking ridges over their entire length (Nowak,
1991; Kingdon, 1997). The horns may grow 7-19 cm in length (Walther,
1990).
Ontogeny and Reproduction
R. campestris breeds throughout the year, although Walther (1990)
also mentions a peak in births in the months of November and December. The
gestation period is approximately 170 days, or just over 5.5 months (Walther,
1990; Kingdon, 1997). Although females possess four mammae (teats),
there is typically a single young per birth (Walther, 1990). Infants
weigh approximately 0.9 kg at birth, and are precocious, able to walk within
five minutes of birth (Walther, 1990; Kingdon, 1997). Despite this
advanced development, steenbok have adopted a "hider" strategy, with the
infant remaining well hidden for two weeks before it begins to follow its
mother while she forages (Kingdon, 1997).
Infants are weaned at approximately 3 months of age (Walther, 1990; Kingdon,
1997). Sexual maturity is reached at the young age of 6-7 months for
females, and after 9 months for males (Walther, 1990; Kingdon, 1997). This
early maturity, coupled with the fact that some females will breed twice
per year, may explain how this species continues to persist in areas
with sustained persecution (Kingdon, 1997). According to Kingdon (1997),
the lifespan of the steenbok is at least seven years, while Walther (1990)
suggests that this species could live until 10-12 years of age.
Ecology and Behavior
Steenbok inhabit savannahs in dry climates, often found in lightly wooded
grassland at altitudes from sea level to 4,750 meters (Nowak, 1991; Kingdon,
1997). In South Africa, R. campestris is typically found in
more open territory, while East African populations favor stony savannah
in Acacia-grassland mosaics (Kingdon, 1997). Kingdon (1997)
reports that steenbok are rarely observed in Miombo (Brachystegia)
woodland, and tend to favor transitional or unstable conditions created by
brush-clearance (either by agriculture, road construction, or elephants).
Riverbeds and belts of thicket provide well-used refuges when steenbok
inhabit open habitats (Kingdon, 1997).
Steenbok are largely diurnal, although in hot weather the activity pattern
will shift to the cooler hours in the early morning and evening (Walther,
1990; Nowak, 1991). The social system of this small antelope appears
to be an independent or solitary existence within a stable pairbond - a pair
of steenbok inhabit a territory of 4 hectares to 1 km2 in size,
but only come together for breeding (Walther, 1990; Kingdon, 1997). During
the female's estrus period, her partner often becomes quite aggressive (Kingdon,
1997). Observations reported by Kingdon (1997) suggest that while the
members of a pair do not interact directly for most of the year, routines
and scent marks keep the animals aware of each others movements and positions
(Kingdon, 1997). Territories are marked with dung-middens, which
are connected by trails which, through use, become marked with secretions
from the pedal glands (Kingdon, 1997). Following defecation, both sexes
scrape at the middens, potentially associating their pedal gland scent with
the dung pile (Kingdon, 1997).
Due to their small body size, adult steenbok have many different predators,
including leopard, caracal, and pythons (Walther, 1990). In addition,
juveniles are depredated by smaller predators like jackals, the Libyan wildcat,
ratel, baboons, eagles, and monitor lizards (Walther, 1990). In the
presence of danger, steenbok first hide, crouching and freezing with the
neck pressed against the ground and ears retracted to avoid detection (Nowak,
1991; Kingdon, 1997). If the threat persists or approaches, the animal
will flee, with fast zig-zagging flight interrupted by attempts at concealment
by lying down flat (Walther, 1990; Kingdon, 1997). Steenbok will also
purportedly seek refuge in aardvark burrows when pressed (Walther, 1990;
Nowak, 1991).
Steenbok are primarily browsers, feeding at or near ground level. Shoots
of most dominant shrub and tree species within their habitat are eaten, including
Acacia, leafwood (Combretum), buffalo thorn (Ziziphus),
Bridelia, and mopane (Colophospermum) (Kingdon, 1997).
Fruits are occasionally consumed, as are sprouts of some grasses during
periods of early growth. Steenbok will also use their sharp hooves
to scrape up selected roots and tubers (Kingdon, 1997). Water is not
essential; steenbok in the Kalahari subdesert may be found as far as 80
kilometers from a permanent water source (Kingdon, 1997)..
Genetics
Steenbok have a karyotype of 2n = 30 (Wallace & Fairall, 1967).
Distribution
Two disjunct populations of steenbok are present, the eastern race being
found from southern Kenya to central Tanzania, and the southern race which
inhabits Angola, western Zambia, Zimbabwe, and southern Mozambique south
to South Africa.
Countries: Angola, Botswana, Kenya, Lesotho, Mozambique, Namibia,
South Africa, Swaziland, Tanzania, Zambia, and Zimbabwe
Range Map (Redrawn from IEA, 1998)
Conservation Status
R. campestris is not listed on the IUCN redlist (2004) nor by CITES
(2005). The total population of steenbok in Africa is estimated at
approximately 663,000 individuals, of which 25% are found within protected
regions and an additional 30% found on private lands (East, 1999).
Remarks
"Steenbok" is actually the Dutch name for ibex (Capra ibex), and despite
the lack of resemblance between the two species, the Dutch settlers (Boers)
gave this small grassland antelope the same name as the mountain goat they
were familiar with from back home (Walther, 1990). Alternatively, it
has been suggested that since steen translates as "stone" or "brick",
steenbok may refer to the reddish color of the animal. Alternate spellings
of the name steenbok include steinbok, steenbuck, and steinbuck. The
genus Raphicerus is derived from the Greek words raphis and
keras, meaning "needle" and "horn" respectively, a reference to the
sharp, straight horns of this genus. Campestris is Latin for
level country or a plain, the habitat this species prefers .
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Local names
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Isha, Dondor [Swahili] (Kingdon, 1997)
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French
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Steenbok (Walther, 1990; Kingdon, 1997)
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Raphicère champètre (Walther, 1990).
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German
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Steinböckchen (Walther, 1990; Kingdon, 1997)
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Literature
Cited
CITES (Convention on the International Trade in Endangered Species of Wild
Flora and Fauna). 2005. Appendix I, II, and III as adopted by the Conference
of the Parties, valid from 23 June 2005. Available online at
http://www.cites.org/
East, R. [compiler]. 1999. African Antelope Database 1998. IUCN/SSC Antelope
Specialist Group. Gland, Switzerland and Cambridge, UK: IUCN.
IEA (Institute of Applied Ecology). 1998. Raphicerus
campestris. 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://www.gisbau.uniroma1.it/amd/amd214b.html
IUCN (International Union for Conservation of Nature and Natural Resources).
2004. 2004 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.
Nowak, R. M. [editor]. 1991. Walker's Mammals of the World (Fifth Edition).
Baltimore: The Johns Hopkins University Press.
Wallace, C. and N. Fairall. 1967. The chromosomes of the steenbok.
South African Journal of Medical Science; 32: 55-57.
Walther, F. R. 1990. Duikers and Dwarf Antelopes.
In Grzimek's Encyclopedia of Mammals. 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/
Additional Resources
Cloete, G., and O. B. Kok. 1986. Aspects of the water economy
of steenbok (Raphicerus campestris) in the Namib Desert. Madoqua;
14(4): 375-387.
Cloete, G., and O. B. Kok. 1986. The distribution and density
of steenboks in the Kuiseb River Canyon, South-West Africa. Madoqua;
14(4): 421-424.
Dasmann, R.F. and A. S. Mossman. 1962. Reproduction in some ungulates
in Southern Rhodesia. Journal of Mammalogy; 43: 533-537
du Toit, J. T. 1990. Home range-body mass relations. A
field study on African browsing ruminants. Oecologia (Berlin); 85(2):
301-303.
du Toit, J. T. 1990. Feeding height stratification among African
browsing ruminants. African Journal of Ecology; 28(1): 55-62.
*du Toit, J. T. 1993. The feeding ecology of a very small ruminant,
the steenbok (Raphicerus campestris). African Journal of Ecology;
31(1): 35-48.
*du Toit, J. T., and C. A. Yetman. 2005. Effects of body
size on the diurnal activity budgets of African browsing ruminants.
Oecologia; 143(2): 317-325.
Gerneke, W. H., and M. Cohen. 1978. The micro-morphology of the
glands of the infraorbital cutaneous sinus of the steenbok, Raphicerus
campestris. Onderstepoort Journal of Veterinary Research; 45(2):
59-66
*Haim, A., and J. D. Skinner. 1991. A comparative study of metabolic
rates and thermoregulation of two African antelopes, the steenbok Raphicerus
campestris and the blue duiker Cephalophus monticola. Journal
of Thermal Biology; 16(3): 145-148.
Hart, L. A., B. L. Hart, and V. J. Wilson. 1996. Grooming rates
in klipspringer and steinbok reflect environmental exposure to ticks.
African Journal of Ecology; 34(1): 79-82.
Hay, L., and W. Van Hoven. 1988. Tannins and digestibility in
the steenbok (Raphicerus campestris). Comparative Biochemistry
and Physiology, Part A: Physiology; 91(3): 509-511.
Mattiello, S., C. Zanoni, H. Du Plessis, E. Heinzl, and M. C. Crimella.
2004. Habitat use and group size of African wild ungulates in
a Namibian game ranch. Game & Wildlife Science; 21(4, Sp. Iss.
SI): 735-745.
Norton, P. M. 1985. Habitat separation of four small antelope
in the Gamka Mountain Nature Reserve, Cape Province, South Africa. South
African Journal of Science; 81(11): 692.
Oates, L. G. 1972. A note on the sex ratio of steenbok,
Raphicerus campestris, in Transvaal lowland Mopane colophospermum
mopane woodland. Koedoe 15: 141-142.
Paias Simoes, A., and J. Crawford-Cabral. 1990. Notice on
large-hoofed steenbok, Raphicerus campestris (Mammalia: Artiodactyla),
from Angola. Garcia de Orta, Série de Zoologica: Lisboa; 15(2): 1-8.
Penzhorn, B. L. 1971. A note on the sex ratio of steinbok
Raphicerus campestris in the Kalahari Gemsbok National Park. Koedoe;
14: 61-64.
Robinson, M. D. 1977. An observation on parental care of young
in the steenbok in south-west Africa. Madoqua; 10(3): 215-216.
Rowe-Rowe, D. T. 1971. Sex ratios of steenbok, Raphicerus
campestris, seen in 2 southern African National Parks. Koedoe 14:
55-59.
Stuart, C. T. 1975. The sex ratio of steenbok, Raphicerus
campestris, in the Namib Desert Park, south-west Africa. Madoqua;
Series II 4(74-80): 93-94
Underwood, R. 1983. The feeding behavior of grazing African
ungulates. Behaviour; 84(3-4): 195-243.
Wilson, V. J., and M. A. Kerr. 1969. Brief notes on reproduction
in steenbok, Raphicerus campestris. Arnoldia (Rhodesia); 4(23):
1-5.
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