MORPHOMETRICS AND REPRODUCTION IN A POPULATION OF SPRINGBOK ANTIDORCAS-MARSUPIALIS IN THE SEMIARID SOUTHERN KALAHARI

The timing and duration of the male rut were monitored in a population of springbok in the Kalahari from 1984. Timing was random and could n ot be related to any proximate factor; the duration varied from 5 to 2 3 days, Springbok rams were shot: or captured in the hot-wet, cold-dry and hot-dry seasons from 1988 to 1992, Body condition and testicular exocrine and endocrine functions were measured, Territorial and non-te rritorial rams were treated in the same way. All body measurements wer e lower for non-territorial than for territorial rams, but only neck g irth differed significantly. Captured animals were stimulated with GnR H and plasma testosterone concentrations were measured over 90 min, Ov erall, non-territorials showed a greater response than territorial ram s, The response of territorial rams to GnRH at the beginning of a rut was significantly less than the response 1 week later, Ewes came into oestrus shortly after the beginning of the male rut; in four of the pa st five years lambing peaked in the hot-wet season. Rams appeared to b e physiologically capable of reproductive activity throughout the year , and responded to various stimuli by exhibiting rutting and/or mating behaviour. The possible stimuli are discussed.