Flexibility and Use of a Novel Tool in Asian Small Clawed Otters (Aonyx cinerea)
Abstract
Asian small-clawed otters ( Aonyx cinerea ) demonstrate remarkable hand dexterity when gathering and consuming prey, but little is known about their ability to use objects as tools. The present study used a tool choice paradigm in which six Asian small-clawed otters were tested individually and presented with two identical hook-shaped tools. For each trial, only one tool was positioned such that pulling it allowed an otter to obtain food. Pulling the other hook resulted in the correct hook being moved out of reach, necessitating selection of the correct tool as its first choice The two males performed above chance levels, but the four females did not. The females’ poor overall performance may have reflected their initial inability to understand the tool choice task. Two of the females’ performances improved by 20% over the course of the trials, and another female showed 5% improvement over time. In addition, some incorrect responses appeared to be due to the development of a side preference, rather than to the configuration of the apparatus. Four of the otters exhibited a significant side bias toward the left, but there were individual differences in how these preferences presented in each otter. For all otters, latency to approach and make a choice on the tool-use task decreased over time, regardless of success. Although otters do appear capable of learning which tool should be used in a forced choice comparison such as the one used here, other factors appear to influence the choices individual otters make.