Outdoor enclosure use and behaviour of adult and cub Asian small clawed otters Aonyx cinereus in summer and winter

The behaviour and outdoor enclosure use of a family of Aonyx cinereus otters were investigated in summer and winter at the Wildfowl and Wetland Trust Washington center, UK. In summer, swimming and paddling (adults and cubs) and diving (adults) were recorded significantly more frequently than in winter, correlated with significantly higher frequencies of use of the water features. For the cubs, the relative frequency of diving was significantly lower compared to winter, as the cubs were still learning to swim and forage underwater. The levels of activity and the diversity of behaviours were higher around feeding times in both seasons. The cubs were already swimming in shallow water at 3.5 months old and in deeper water at 4.5 months-old, mostly as a family group. At 3.5-6 months-old they were out of sight in the den significantly more frequently than the adults and displayed more play-fighting. By 8-9.5 months-old they moved around independently, foraging or playing and their behavioural budget was similar to that of the adults. Object juggling and vigilance standing were displayed from around 4 months-old, when weaning also occurred. The introduction of additional structural enrichment (logs, holt, nest-box) in early autumn increased the frequency of use of ground areas in winter, when the water temperatures were below 10 °C. The feeding and structural enrichment strategies used were effective for keeping the otters active outdoors and maintaining their high display value in the cold season (day time summer air temperatures 15-27 °C > winter 3.5-10 °C), emphasizing the importance of enrichment for good welfare.