The endangered Florida manatee (Trichechus manatus latirostris) is a semi social marine mammal with a low reproductive rate and high maternal investment. These life history traits have imposed selective pressures for accurate individual recognition, especially between cow and calf, and manatees use vocal cues to communicate with conspecifics. However, little is known about the occurrence and frequency of manatee vocalizations over time and in conjunction with broad behavioral states (e.g. feeding). The rescued manatee population (n = 9) at the Miami Seaquarium, in Miami, FL was assessed to examine vocalizations patterns when feeding (10 min both before and after food introduction), temporally (10 min in each AM and PM: diel effect), and between male and female manatees. The Dolphin Ear Hydrophone System and a voice recorder was used to record acoustic data, the spectrograms of which were analyzed in Raven Pro 1.5. Manatee vocalization rate was significantly greater before than after the introduction of food, but no diel effect was observed when all pools were analyzed collectively. However, AM vocalization rates were significantly greater than in the PM for 2 of 3 pools. Overall, males vocalized more often than females in general and in the AM, but no difference between sexes was noted in the PM. Variability in the vocalization patterns of manatees can potentially help us identify when manatees congregate and communicate most frequently. This information can be used to help determine the optimal time for rescued manatees to be released in order to maximize success after release and integration with wild populations of manatees.
Civelek, Cylia, "The frequency of vocalizations exhibited by rescued Florida manatees (Trichechus manatus latirostris): the influence of time of day, sex, and feeding." (2013). Internship Reports (Restricted). 168.
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