Bontebok

Distribution

Bontebok are confined in their distribution to a restricted area in the southwestern Cape Province, lying between Bredasdorp and Cape Agulhas. Historically their area of occurrence was somewhat larger, extending from Bot River to Mossel Bay and inland to the Sondereind and Langeberg mountains (Bigalke, 1955). Many of the early travellers first saw them near Caledon, where Isaac Schrijerer's Journal of 1689 recorded that more than 1 000 were seen. Sparrman (1786) also recorded their presence in this area. In these early times there was a measure of confusion in identification between the bontebok and the blesbok. Cornwallis Harris (1840) wrote of "bontebok" as far north as the Magaliesberg in the Transvaal, which were certainly blesbok. Since the time of the early settlement in the Cape there was a distance of some 320 km between the limits of distribution of the two. Bryden (1936) noted that blesbok were never found in the Cape Province, west of Colesberg, and did not occur in the Great Karoo. At one time the species D. dorcas must have had a wide and continuous distribution in southern Africa. Through climatic changes at some geological period of time it became split into two populations which, over the intervening ages, have diverged in characters, leading to the recognition of the two subspecies we see today, the bontebok, D. d. dorcas, and the blesbok, D. d.phillipsi.

It is appropriate that tribute be paid to Mr. P . V. van der Byl, his son, Mr. A. van der Byl, and the van Breda and Albertyn families, for without their recognition of the perilous situation of the species they might well have become extinct. The van der Byls took steps in 1837 to set aside a portion of their farm "Nacht Wacht" near Bredasdorp as a reserve for a nucleus of some 27 individuals. This example was followed by adjoining landowners on the farms De Groote Eiland, Bushy Park and Zoetendals Vallei (Bigalke, 1955). In 1931 the first Bontebok National Park was proclaimed on an area near Swellendam and 84 bontebok were moved to it by truck. By 1969 it was estimated that the numbers had grown to around 800. Since then the National Parks Board of Trustees have made available their surplus stock to farmers and reserves in the Cape Province and by these measures have ensured the survival of the species for the future. Bontebok, nevertheless, remain the least common antelope in the Southern African Subregion.

Description

A dark coat contrasting with white rump patch that surrounds tail; lower legs are white all around; white facial blaze continuous from nose to base of horns.

Categorical-discrete (CD) distribution model

The bontebok is endemic of fynbos biome. Water bound (Lynch, 1983; East, 1989; Mills & Hes, 1997; Kingdon, 1997).

Bontebok are a diurnal, gregarious, grazing species. Their social organisation consists of territorial males, females herds and bachelor groups. The territorial males establish and maintain a mozaic of territories varying in size from four to 28 ha on an all year round basis. Some males may hold their territories for much longer periods, even for the duration of their adult lives. They rarely manage to establish a territory before they are three years of age, generally five years (David, 1970). They acquire these by deposing a territorial male from his territory or by establishing a new one. They defend these from trespass by other males by a complicated system of ritual displays, seldom if ever resorting to fighting.

Reproduction

Bontebok are short-day seasonal breeders, mating in early autumn in the Bontebok National Park, where the rut takes place between the months of January to mid-March, with some activity continuing until April (David, 1973). The territorial males court the females with a display involving tail over the back and holding the head low with outstretched and the tail horizontal. Flehmen does not occur in bontebok. A male may sniff the vulva of a female and if she is not receptive she will run around him closely to avoid his attentions. During this "mating circling" the female holds her head low in the submissive attitude. During the rut the frequency of the courtship display may be as high as once an hour, but is not confined to the period of the rut and may be performed in all seasons of the year. When the male performs to females about to leave a territory, it may actuate them to remain (David, 1970). The annual cycle in the male matches that in the female (Skinner et al., 1980).

Conception rate is influenced by rainfall (which in turn affects grass cover) prior to the breeding season (Novellie, 1986), as well as food availability, as influenced by competition for food by grazers. The gestation period is between 238 and 254 days. Lambs are born in the spring, between

September and November, with late arrivals up to the end of February, the peak months being September/October. Females become sexually mature at just over two years old, having their first lambs at about three years old. The young females remain with their mothers after their new lambs are born, as a member of the herd (David, 1975).

Females have one pair of inguinal mammae.

http://www.wta.org.za/info/mammals/bontebok.htm