<p>Chemoreception represents a primitive sense in many mammals. Although evidence of functional olfaction is described in some cetaceans and pinniped species, findings considering Sirenians are scarce. We investigated the reactions of three Antillean manatees under human care to chemical stimuli: two food-related stimuli, one social-related stimulus and frozen water (control). A fish aggregation around the diffuser on manatees’ behavior was also monitored to test its influence on manatees’ behavior. Behaviors related to interest, social groupings and acoustic activity were recorded. The results showed that the density of fish around the diffuser influenced the manatees’ visual orientation and vocal rate. The manatees were also more present in the test area and decreased the duration and peak frequency of their calls after the diffusion of the feces odor compared to the control condition. Finally, they spent less time close to the device during fennel (plant) diffusion compared to the control condition. This work provides new evidence to the functionality of chemical perception in manatees. It also discusses the implication of other sensory cues and learning mechanisms in their foraging behaviors. We suggest that investigation of manatees’ reactions to environmental changes should include behavioral and acoustical measure.</p>