The behavioural ecology of African clawless otters, Aonyx capensis, in KwaZulu-Natal, South Africa

Abstract

African clawless otters (Aonyx capensis) are the most widely distributed otter species in Africa, and they occur in a wide variety of habitats. Despite their extensive distribution there is a paucity in knowledge on their ecology and, especially their social behaviour. Latrines play important roles in intraspecific olfactory communication of many mammals. In this research project several aspects related to latrine sites and the role these sites play in the behavioural ecology of African clawless otters were assessed. Latrine site selection, population densities, activity time, and scent-marking behaviours were investigated and compared across two study areas (uMlalazi Nature Reserve and Zini Fish Farm) on the north coast of KwaZulu-Natal, South Africa. In addition, volatile organic compounds (VOCs) of 14 African clawless otter scats were described through gas chromatography mass spectrometry (GC-MS). Most of the latrine sites were located at the ecotone between two vegetation units or at the ecotone between a vegetation unit and a water source and were associated with little vegetation cover but lower wind exposure. It is hypothesised that this may increase their conspicuousness to conspecifics, while areas exposed to less wind likely aid in the retention of scent. Otters were strictly nocturnal around latrine sites and behaviours recorded were dominated by sprainting (“jiggle dances”) and sniffing suggesting latrine sites to be important for intra-specific communication. Many of the identified VOCs are commonly associated with reproduction and sex pheromones in other animals. This, combined with substantial inter-scat variation in VOCs, lend further support to the hypothesis that latrine sites are mainly used for intra-(and not inter) communication purposes. Future research will benefit from individual-level identification of otters when investigating the olfactory landscape of latrine sites and the interpretation of their social function to African clawless otters.