Raphicerus sharpeiSharpe's grysbok

Geographic Range

Sharpe's grysboks, Raphicerus sharpei, are constrained south of the equator in central and southern Tanzania to northeastern South Africa. (Nowak, 1991)

Habitat

Raphicerus sharpei may be found in a variety of habitats but most often in rocky, hilly country. These animals seem to avoid large areas of grass standing greater than 50 cm tall, and appear to require some shrub thickets and areas with undercover, as are often found in secondary growth forest. Sharpe's grysboks have been documented in areas with little ground cover, though this is abnormal relative to most recorded observations of habitat use. (Nowak, 1991; Smithers, 1983; Spinage, 1986)

Physical Description

Sharpe's grysboks are small, with a mass of 7 to 16 kg, a height of 45 to 55 cm, a head to body length of 65 to 75 cm, a tail length of 4 to 8cm, and a horn length (males only) of about 5 cm. The largest horn length on record is over twice the normal length, at 10.48 cm. Females of this species are slightly larger than the males, but information on individual ranges was not available. (Nowak, 1991; Smithers, 1983; Spinage, 1986)

Body color is a rufous to reddish brown broken with speckles of white giving the animal a grizzled appearance. The sides of the face, forehead, upperparts of the muzzle, and outer parts of the limbs are a yellowish-brown color. The belly, underside of the neck, and inside of the legs and ears are a buffy-white. A whitish ring around the eyes extends as a line down the sides of the muzzle to the rhinarium. (Nowak, 1991; Smithers, 1983; Spinage, 1986)

Raphicerus sharpei is easily distinguished from other members of the genus. Raphicerus sharpei lacks false hooves as does Raphicerus campestris (steenbok) whereas Raphicerus melanotis (grysbok) has false hooves. The normal tooth formula for Sharpe's grysboks is 0/3 0/1 3/3 3/3. Child and Riney (1964) found only 1 case of abnormal dentition in 121 examined specimens (0.83%) that were from a small area of Southern Rhodesia. The abnormality was found in a female that had upper canines. (Child and Riney, 1964; Nowak, 1991)

  • Range mass
    7 to 16 kg
    15.42 to 35.24 lb
  • Range length
    65 to 75 cm
    25.59 to 29.53 in

Reproduction

Information pertaining to the mating system of the Sharpe's grysboks was not available. However, other members of the genus may be polygynous or pairs may defend territories together. It is likely that these animals are similar to congeners. (Nowak, 1991)

Raphicerus sharpei can breed throughout the year. Most records show a peak in breeding between November and December. This proposed peak coincides with the start of the spring rains in southern Africa where this species is found. After a gestation of approximately 180 days (ranging from 168 to 210 days) one to two young will be produced. Weaning of the young will occur at 3 months of age and sexual maturity will be reached for both sexes after 6 to 19 months. (Nowak, 1991; Smithers, 1983)

  • Breeding interval
    These animals are apparently capable of breeding annually.
  • Breeding season
    Raphicerus sharpei can breed throughout the year, but births are timed to coincide largely with the start of the rainy season.
  • Range number of offspring
    1 to 2
  • Range gestation period
    5.6 to 7 months
  • Average weaning age
    3 months
  • Range age at sexual or reproductive maturity (female)
    6 to 19 months
  • Range age at sexual or reproductive maturity (male)
    6 to 19 months

Little information is available on the parental care of this species. As in other mammals, the female provides the bulk of the parental care. Female Sharpe's grysboks will begin weaning young when offspring reach about 3 months of age. At 6 to 19 months of age, offspring will have reached sexual maturity and are already independent. The role of the father in parental care has not been recorded. (Nowak, 1991; Smithers, 1983)

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • protecting
      • female

Lifespan/Longevity

Information pertaining to the lifespan/longevity of the Sharpe's grysbok was not available.

Behavior

Sharpe's grysboks are secretive animals, usually spending most of the day lying in thick cover. Their activity is generally nocturnal and solitary. But, although mostly solitary, adult pairs or a female with offspring may be seen throughout the year. (Nowak, 1991; Smithers, 1983; Spinage, 1986)

Sharpe's grysboks are territorial, usually defending territories alone, although pairs may defend a single territory together. The male territorial fighting is said to be less ritualistic than in most antelopes, simply involving a straight, forward stride into battle, a lowering to the knees and stabbing or meeting of the short horns. (Spinage, 1986)

When frightened by a predator, R. sharpei rarely runs, instead lying flat with an outstretched head and neck in thick undercover until a predator may be nearly on top of them. In the chance that R. sharpei may have to run, such fleeing takes place with a deliberate crouch. An animal stays low to the ground. These grysboks are known to use old burrows, especially those of aardvarks, when in search of protection from predators. (Nowak, 1991; Smithers, 1983; Spinage, 1986)

Due to the secretive nature of this species, habit studies are difficult and therefore, relatively little information is known. (Smithers, 1983)

Home Range

Information pertaining to the home range of R. sharpei was not available.

Communication and Perception

Raphicerus sharpei possesses preputial, eye and facial glands that are used in scent-based communication. In addition, these animals use tactile communication in fighting and mating, as well as between mothers and their offspring. Some visual communication may occur, with regard to body posturing, especially during aggressive encounters. (Spinage, 1986)

Food Habits

All members of the genus Raphicerus are browsers and grazers. A study conducted in southeastern Zimbabwe by Wilson examined the stomachs of 91 R. sharpei specimens and found that it is predominantly a browser, with browse accounting for 70% of the stomach contents. Sharpe's grysboks will feed on some fruit as well as roots and tubers they unearths with their hooves. They apparently do not require access to free water but, if available, will drink it. (Nowak, 1991; Smithers, 1983)

  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems
  • fruit

Predation

Sharpe's grysboks usually use thick vegetation and dense undercover to hide from predators. They will use old burrows, especially of aardvarks, as means of evading from predators. (Smithers, 1983; Spinage, 1986)

Ecosystem Roles

Little information about the ecosystem roles served by the Sharpe's grysboks has been documented. Given its status as a prey species to numerous predators, it is assumed that its role as a food source for carnivorous predators is important. It is likely to affect vegetative growth through its browsing behavior. (Spinage, 1986)

Economic Importance for Humans: Positive

Sharpe's grysboks are of positive economic value to humans as they are hunted for meat, hide and sport in many areas throughout the species' range. ("South Africa Safari", 2001)

  • Positive Impacts
  • food
  • body parts are source of valuable material

Economic Importance for Humans: Negative

It has been reported that this species may cause damage to crops. (Nowak, 1991)

  • Negative Impacts
  • crop pest

Conservation Status

Nowak (1991) reported that this species may be threatened by human sprawl in East Africa and has become rare in some parts of their range. The IUCN Red List classifies this species as a lower risk, conservation dependent species (LR/cd). The major threats identified by the IUCN are habitat loss due to the spread of the human population and ongoing harvesting by hunters. Given the large national parks in southern Africa and the populations of Sharpe's grysboks found within these parks, there is little concern of serious decline of this species if continued conservation of National Park land persists. ("The IUCN Red List of Threatened Species", 2002; Nowak, 1991)

Other Comments

Historically, Ansell split this R. sharpei into two subspecies. In the northern parts of the range it was classified as R. s. sharpei and in the southern parts of the range was classified as R. s. colonicus. The geographic borders of these subspecies and their validity are still in question. Most literature does not refer to subspecies. (Smithers, 1983)

It has been suggested by Kingdon that R. sharpei may be more closely related to the dwarf antelopes of the genus Neotragus than to other species of the genus Raphicerus. (Nowak, 1991)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Scott Hocking (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

African Safari Consultants. 2001. "South Africa Safari" (On-line). Accessed December 02, 2002 at http://www.safariconsultants.com.

IUCN. 2002. "The IUCN Red List of Threatened Species" (On-line ). Accessed 12/02/02 at http://www.redlist.org/search/details.php?species=19307.

Child, G., T. Riney. 1964. Abnormal dentition in the Common duiker (*Sylvicapra grimmia*), Impala (*Aepyceros melampus*) and Sharp's grysbuck (*Raphicerus sharpei*). Occasional Papers of the National museum of Southern Rhodesia, 27B: 1-4.

Nowak, R. 1991. Walker's Mammals of the World- Vol II, 5th ed.. Baltimore, MD, USA: John Hopkins University Press.

Smithers, R. 1983. The Mammals of the Sothern African Subregion. Pretoria, South Africa: University of Pretororia.

Spinage, C. 1986. The Natural History of Antelopes. New York, NY, USA: Facts On File Publications.