Mist nets, ultrasonic sensors, light tags and feces analysis were used to examine habitat use, activity patterns and prey selection of some insectivorous bats during the dry season at the Sengwa Wild Life Research Area (18.degree.10''S; 28.degree.13''E) between June 7 and 28, 1977. Broad overlap in all parameters investigated was shown for the 13 spp. [Eptesicus capensis, Nycticeius schlieffeni, Scotophilus viridis, Hipposideros caffer, Pipistrellus nanus, P. rueppelli, Laephotis angolensis, Miniopterus schreibersi, Nycteris thebaica, N. woodi, Tadarida aegyptiaca, T. chapini and Rhinolophus sp.] present in the area during the dry season. During the wet season, some species of insectivorous bats relied more on beetles than on moths as food, or vice versa. The lack of food partitioning, particularly in the dry season, appears to conflict with theories of niches and competitive exclusion but is in accord with predictions based on optimum foraging strategy. Most insectivorous bats may be opportunistic feeders, a strategy which results in a mosaic of specialized and generalized diets and which compatible with their energetic demands. The 1st record of T. chapini from Zimbabwe (Rhodesia) was reported.