BEHAVIOR OF NILE CROCODILES IN A SEASONAL RIVER IN ZIMBABWE

Nile crocodiles congregated in the Chipinda Pools of the Runde River i n the Gonarezhou National Park in Zimbabwe during the dry winter of tw o drought years, and adults and subadults dispersed upriver when the r iver flowed during the wet summer. juvenile crocodiles moved overland through forest during the wet season and inhabited temporary ponds. Cr ocodiles courted and mated in a shared courtship-mating arena in front of a shared basking ground during winter; after courting and mating, individuals basked and slept. Crocodiles basked most frequently during cold July, first coming onto shore when direct sunlight was on the ba sking ground, and least during summer. The group of basking crocodiles consisted of reproductive and nonreproductive individuals, adults and subadults of both sexes, including dominant breeding bulls. Aside fro m exclusion of juveniles, spacing and distribution of basking crocodil es was without regard to sex, dominance, or reproductive status. Baski ng sites were never defended as exclusive territories. Gaping by baski ng crocodiles during winter was usually a threat display, used when an other animal drew near (e.g., crocodile, hippopotamus, bird, human). H ippopotamuses also basked during winter and often displaced crocodiles from their basking sites. Crocodiles did not congregate at Chipinda P ools during a nondrought year, even for courtship and mating.