Seasonal changes in the behaviour and enclosure use of captive Asian Small Clawed Otters (Aonyx cinereus)

The influence of seasonal changes in temperature on the behaviour of tropical mammals kept in zoos and aquaria in temperate climate regions is very little studied. This article describes seasonal differences in the behavioural time budget and enclosure use of two male Asian small-clawed otters (Aonyx cinereus) held in an indoor enclosure at the Blue Reef Aquarium Tynemouth in the North-East of England (55°N). The otters studied spent significantly more time in the water in summer (water temperature 18-19°C) than in winter (water temperature 11-12°C). Swimming represented 33.4% of the total summer observation time, compared to only 14.1% in winter. In summer, the otters were seen in water at 33.7% of the sampling times, in the deep or shallow pool or in the river in the enclosure, compared to 15% in winter. In both seasons, the time budget also included 32-34% active behaviours on land, 15-17% maintenance, 5-8% affiliative social interaction and 2-3% being out of sight. In winter, the otters were more aggressive (winter 2% > summer 1%) and less active, with significantly more time spent lying down resting or sleeping (winter 11% > summer 4.6%) or being vigilant, looking around or ‘begging’ at the keeper or visitors (winter 12.2% > summer 5.8%). Feeding anticipatory activity was seen in both seasons. Affiliative social interaction occurred mainly between feeds, linked to rest periods. The relevance of these observations is discussed in relation to thermoregulation and possible effects on reproduction.