ABS 2022
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Putting Smooth-Coated Otter Vocalizations into Context 
Philip Johns1, Sarah Lim1, Yugal Nathoo1, Zhi Yi Yeo1, Raunak Vijayakar1, Niki Lee2. 1Yale-NUS College, Singapore, , Singapore; 2National University of Singapore, Singapore, , Singapore

Smooth-coated otters (Lutrogale perspicillata) returned to Singapore in recent years, and their growing urban population allows for some of the best conditions to observe otter behavior anywhere. Smooth-coated otter romps consist of a dominant pair and one or more successive broods. These otters are gregarious and vocal. Here we observed and video recorded urban otters in situ. We used a supervised machine learning algorithm to isolate over 12000 otter vocalizations from other noises recorded in over 3300 videos, then clustered the vocalizations into more than 20 call types. We subsampled videos to find associations between call types and otter behaviors. We then analyzed sequences of vocalizations and otter behaviors to put otter calls into contexts. We found evidence that otters use vocal communication to coordinate some behaviors, including group foraging. We discuss these results in the context of otter social behavior, urban wildlife, and citizen science.