TROPHIC OVERLAP BETWEEN 3 SYNTOPIC SEMIAQUATIC CARNIVORES - CAPE CLAWLESS OTTER, SPOTTED-NECKED OTTER AND WATER MONGOOSE

Drought conditions in the Eastern Cape Province, South Africa, from 19 90 to 1993 caused much of the Bushmans River to dry up, thus forcing C ape clawless otters Aonyx capensis (Schinz), spotted-necked otters Lut ra maculicollis (Lichtenstein) and water mongooses Atilax paludinosus (Cuvier) to coexist in restricted ranges. The diet of the three carniv ores was compared by analysing their seats to determine the amount of trophic overlap. Expressed as relative percentage frequency, the three most common prey categories found in Cape clawless otter seats were c rab Potamonautes perlatus (Milne Edwards) (51%), insect (19%) and fish Tilapia sparrmanii (Smith) (18%). In spotted-necked otter seats, fish (47%), crab (38%) and frog (8%) were the most common, while in water mongoose seats, insect (28%), crab (26%) and mammal (15%) were most ab undant. Water mongooses and spotted-necked otters ate similar sizes of crabs, significantly larger than those eaten by the Cape clawless ott ers. Cape clawless otters ate a wide range of crab sizes, including sp ecimens much larger than those taken by the other two carnivores. Cape clawless otters and water mongooses ate similar size fish, significan tly smaller than spotted-necked otters. The results show that even dur ing enforced cohabitation in a relatively small range during drought c onditions, there is separation of diets in these three carnivores.