Human presence and sexual activity of West Indian manatees (Trichechus manatus) at Crystal River, Florida

Free-ranging manatees wintering in the warm water of Kings Spring, Crystal River, Florida, were studied to determine the relationships between human presence and their sexual behaviors. The manatees of Crystal River are unique because of frequent exposure to large numbers of snorkelers and divers. Quantitative knowledge of such relationships are becoming increasingly important as preservation measures are reviewed to ensure that the human activity at the Spring does not pose a threat to manatee reproduction. Focal animal sampling provided sexual behavioral data of manatees during randomly selected 30 min sampling periods. Frequencies of four of the eight observed sexual behaviors increased significantly in the presence of humans. Differences were also found between the types of sexual behaviors manatees exhibited while interacting with conspecifics, and the behaviors displayed with humans. Manatees appeared to be hyperstimulated in the presence of humans. No conclusions could be made about the effects of human interaction on manatee reproductive success because of the relatively short duration of the study.