Nesting ecology of Nile crocodiles (Crocodylus niloticus) in the Olifants River, Kruger National Park

Abstract

Data on the nesting behaviour of Crocodylus niloticus along the Olifants River in the Kruger National Park were collected over a period of six years (1993 to 1998). A total of 165 nests were investigated for soil type, exposure to sunlight, distance to and above water, presence of other nests and vegetation. An attempt was made to determine important factors in the placement of nests, and exposure to sunlight, vegetation and distance to water seemed to be crucial in selecting a nesting site. During the last two seasons 20 nests were opened and the nest contents recorded. Some 795 eggs were measured and the data compared to similar studies in Africa. No significant differences were found. A strong correlation was found between egg mass, length and female size with larger females producing larger eggs. Rainfall influenced the size of nesting females as only larger females (>3 m TL) nested during the dry year. Breeding females along the Olifants were overall larger (TL) than in Zimbabwe with 2.1 m as the smallest and 4.1 as the largest females that nested.