You Otter Not Talk: A Preliminary Study of Asian Small-Clawed Otter Vocalizations and Activity in the Presence of Visitors and Staff

Otters spend a considerable amount of time vocalizing within zoos and other captive settings. Although associations between these vocalizations and social activity have been investigated prior, it is not always clear how this is reflected in interactions with people under typical zoo conditions, including interactions with zoo visitors and staff. In addition, the implications for zoo welfare and their relation to vocalizing are also not clear, warranting greater investigation to identify potential future welfare metrics for otter species. We examined zoo Asian small-clawed otter vocalizations and general activity in the presence of people, including both visitors and staff. Our focus was on measuring vocalizations as a binomial response (yes/no) in relation to two variables: (a) people, and (b) time. In addition, we also measured differences in vocalizations during sessions, when visitors were present with or without staff. Finally, we measured general otter activity during sessions when 50% or more of the observation intervals had people present (More People), as opposed to sessions where less than 50% of all intervals had a person present (Less People). Overall, otters were statistically more active and less out of sight when more people were present; a weak to moderate correlation was observed between vocalizations and people, a weak correlation was observed between vocalizations and time, and there was no statistically significant difference in vocalizations of the otters in the presence of visitors regardless of staff presence. These results suggest that the measured variables showed no evidence of an overtly negative visitor effect for the otters and may have produced a potentially enriching effect. In addition, measuring multiple variables, including time of day, diurnal patterns, feeding patterns, weather, and providing experimental control could aid in identifying the potential visitor effect for otters and other zoo animals.