A study of the social behaviour of the Roan antelope, hippotragus equinus equinus (Desmarest, 1804) in the Kruger National Park

Abstract

An analysis of the social behaviour of the roan antelope (Hippotraqus equinus equinus Desmarest, 1804) is presented in this thesis. The study commenced in

A herd of 10 animals in an enclosure - 1,6 kilos square and simulating natural conditions - provided ideal opportunities for intensive study: Further observations were made on free-roaming herds in the main roan habitat of the Park i.e. the Lebombo flats north of the Letaba river, The basic discipline regulating the interactions between the members of a herd is the dominance hierarchy. According to this system the social standing of each individual in the herd is determined by its degree of dominance over other herd members. The position amongst males differs from that of the females insofar as the dominance - which allows for conditional tolerance towards

other individuals is replaced by total intolerance amongst adult males. This rules out any possibility of an amiable co-existence between adult bulls~ h straight-line dominance hierarchy is evident amongst the cows. Characteristically the leadership 0£ the herd is the function of the most dominant cow; Among the immatures dominance is determined by age and not sex. Rank positions among females remain unchanged in tho transition from immature to adult: Dominant individuals assert their dominance over subordinates by means of the dominance display and low-moderate and high intensity fighting; Once established, the positions remain stable., stability:

The dominance hierarchy results in herd stability. The characteristic mosaic pattern found in the distribution of roan herds may be attributed to both social and ecological factors. Socially, herd stability and the various zones occupied by a herd are the major factors. Adult roan bulls defend an 'intolerance zone' of approximately 600 m diameter. Other adult males are challenged upon entering this zone. Evidence of an intolerance zone and the difference between it and a territory proper is presented~ The existence of a dominance hierarchy results in 'closed' social units (herds) and therefore inhibits other females from leaving one hard to join another; The area occupied by a herd throughout the year is referred to as the activity zone. The various herds' activity zones do not overlap. activity zone marking is accomplished by both visual and olfactory means. Available activity zones in the Park are occupied and therefore the roan population is considered stable;

The mating behaviour of roan is described with an evaluation of the various phases viz. spacial relationship between bull and cow, dominance, smelling of the cow's tail and vulva, 'Flehmen', Laufeinschlag', standing firm of the female, copulation and post-copulatory behaviour;

A detailed account is given of the mother/calf and calf to calf relationships: The concealment behaviour of the calf during the first 6 weeks of life is given, with special emphasis on the means by which effective concealmemt is achieved; Other activities, such as playing, are also mentioned: Communication between mother and calf may be both visual and auditory. Auditory communication could not be confirmed but this may have been due to field conditions. Tho survival value of tho mother/calf relationship

is tested against various decimating factors. The conclusion is that the mother/calf relationship is well adapted

to prevailing conditions in the Park and that no abnormally high mortalities could be ascribed to this system.