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Raphicerus melanotisCape grysbok

By Lindsey Fowler

Geographic Range

Cape grysboks, Raphicerus melaotis, are endemic to South Africa. They inhabit a small range from Zululand to Cape Province. (Haltenorth and Diller, 1980)

Habitat

Cape grysboks prefer open grassy plains for foraging and thick areas of bush for hiding during the day. They range from arid savannahs to moist reed belts. (Haltenorth and Diller, 1980)

Physical Description

Closely resembling Raphicerus campestris, or steenboks, cape grysboks are small antelopes. These animals are rather stocky, measuring 45 to 55 cm at the shoulder, and weighing between 8 and 23 kg. Straight, needle-like horns of 6.5 to 13 cm are found only on males, which are also darker in color than are females. The pelt is comprized of stiff, wiry hairs. Both adults and young have reddish-brown pelage dorsally, with a red underside and a reddish-yellow throat. White hairs sprinkled along the back, from the nape to the tops of the legs, give these antelopes a grizzled appearance. A dark Y-shaped marking can be found running from the forehead down to the nape of the neck. The ears are large with white radial stripes on the inside. The lateral hooves are very small and sometimes absent and small false hooves are present. Foot glands and pre-orbital glands are present and well developed. (Dorst and Dandelot, 1969; Haltenorth and Diller, 1980; Kingdon, 1982)

  • Range mass
    8 to 23 kg
    17.62 to 50.66 lb

Reproduction

No specific breeding season is recorded for grysboks. However, males are reported to be completely intollerant of one another. They fight feircely, and cannot be housed together in captivity. In addition, males are territorial, and mark their territories with dung heaps, scent marks, and urine. Pairs may associate and defend territories together. This indicates that mating is probably polygynous or monogamous. (Nowak, 1999)

Young are seen year round, however there is a peak from September through December. One young is born after a six-month gestation. Other details of reproduction and rearing have not been observed but are presumed similar to those of steenboks. (Dorst and Dandelot, 1969)

  • Breeding interval
    These animals are probably capable of producing one young per year.
  • Breeding season
    There is no breeding season, but births peak from September through December.
  • Range number of offspring
    1 (low)
  • Average number of offspring
    1
  • Average gestation period
    6 months

Parental care is reported to be similar to that of steenboks. Studies have not been further conducted with grysboks. it is likely that the female nurses, protects, and grooms her offspring. The role of the father in parental care has not been reported. (Dorst and Dandelot, 1969)

  • 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

Grysboks have lifespans similar to Raphicerus campestris. (Kingdon, 1982)

Behavior

Cape grysboks are generally nocturnal, becoming active late in the afternoon. They seek out open areas for grazing under the cover of darkness. During the day, they can be found resting in bushes or in the shade of rocks. They are reported to be solitary animals, with their only sociality during mating. When threatened, grysboks will lie flat in the grass. If pursued, these animals will run with a zigzag-gallop and dive into a hole to avoid predation. Vocalizing (in the form of bleating screams) only occurs when an individual is caught. (Dorst and Dandelot, 1969; Haltenorth and Diller, 1980)

Home Range

Each animal has a well-defined home territory. These are marked with defecation/urination sites and pre-orbital gland scent markings. Population density is low, with approximately one animal per square mile (Haltenorth and Diller, 1980)

Communication and Perception

Scent marking is the main form of communication among grysboks. They have very well developed preorbital glands that secrete a sticky, black substance with a distinct odor. However, as mammals, it is likely that there are some other forms of communication. Tactile communication occurs between mates, parents and offspring, and between rivals when fighting. Visual signals, based on body posture, probably are important as well. (Kingdon, 1982)

Food Habits

Grapevine shoots are the preferred diet of Cape grysboks. They also ingest grasses, fruits, and bush and tree foliage. These antelope are reportedly able to survive long periods without water, and some home ranges have no free water in them. (Dorst and Dandelot, 1969; Haltenorth and Diller, 1980; Nowak, 1999)

  • Plant Foods
  • leaves
  • roots and tubers
  • fruit

Predation

Because of their small size, grysboks fall prey to many animals. They are hunted by leopards, jackals, crowned eagles, and pythons, as well as humans. ("Trophy Hunting", 2002; Kingdon, 1982; "Trophy Hunting", 2002)

The antipredator behavior of these animals is larely based on their small size. These animals try to hide from predators in vegetation, perhaps in the hopes of going unnoticed. If pursued, they will try to go down a hole, such as those made by aardvarks. (Nowak, 1999)

Ecosystem Roles

Cape grysboks are a prey item for a number of large carnivores. They probably have some influence on plant growth through their browsing behaviors. (Kingdon, 1982)

Economic Importance for Humans: Positive

Cape grysbok are a common game animal, with trophy prices ranging from $300 to $900 US dollars. They are hunted with dogs. Although these animals may sometimes be eaten, the meat is reported to be dry and is not highly desired. (Nowak, 1999; "Trophy Hunting", 2002)

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

There are claims it that grysboks damage crops, however this is not seen as a substantial issue. (Kingdon, 1982; Nowak, 1999)

  • Negative Impacts
  • crop pest

Conservation Status

IUCN Red List Threatened Animals 1996 - Conservation dependent ("ICI Naturelink", 2002)

Other Comments

Cape grysboks have very sharp hearing, which helps them remain elusive. They seem to adapt well to the presence of humans, but prefer to inhabit areas with little human development. (Kingdon, 1982)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Lindsey Fowler (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

agricultural

living in landscapes dominated by human agriculture.

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.

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

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.

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

scrub forest

scrub forests develop in areas that experience dry seasons.

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

suburban

living in residential areas on the outskirts of large cities or towns.

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

ICI. 2002. "ICI Naturelink" (On-line ). Accessed 10/28/02 at http://www.ici.com/icishe/naturelink/species/species2321.htm.

Sutton Safaris. 2002. "Trophy Hunting" (On-line ). Sutton Safaris. Accessed 10/28/02 at http://suttonsafaris.eci.co.za/Trophies.htm.

Dorst, J., P. Dandelot. 1969. A Field Guide to the Larger Mammals of Africa. Boston: Houghton Mifflin Company.

Haltenorth, T., H. Diller. 1980. The Collins Field Guide to the Mammals of Africa Including Madagascar. Lexington: The Stephen Greene Press.

Kingdon, J. 1982. East African mammals: An atlas of evolution in Africa.. London: Academic Press.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: The Johns Hopkins University Press.

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