Captive Male and Female West Indian Manatees Display Variable Vocal and Behavioral Responses to Playbacks of Conspecifics

Abstract

Manatees exhibit diverse vocalizations in various behavioral contexts, but the exact role of these sounds, particularly in terms of sex‐based distinctions, remains elusive. This study sought to discern the behavioral and vocal responses of two subspecies of captive West Indian manatees ( Trichechus manatus ) to different call types (squeaks and squeals) to determine whether differences are related to the sex of the signaler. In Mexico, four female Antillean manatees ( Trichechus manatus manatus ) were subjected to playbacks, while in Florida, two male Florida manatees ( Trichechus manatus latirostris ) were used for a parallel experiment. Vocal responses were captured using two hydrophones, with an underwater speaker system facilitating the playback. Video footage was collected to observe behavioral changes in response to playback. Results indicated that neither male nor female manatees increased the number of calls, changed call type, or altered acoustic parameters regardless of call type or whether the sound played was male or female. Likewise, neither males nor females significantly altered their behavior or movement towards the speaker in response to male or female calls, or call type. However, individual Antillean manatees exhibited variation in their behavioral responses to playback of conspecific vocalizations. The results suggest that manatees may not distinguish between the sex of callers.

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