SARASOTA, Fla., Nov. 28 (UPI) -- University of South Florida College of Marine Science researchers are testing manatees' hearing to help them avoid being injured or killed by boat strikes.
Professor David Mann and colleagues want to determine the frequencies to which manatees best respond. "The ability of manatees to hear and localize boat sounds is important for their survival," said Mann.
Approximately 3,500 manatees live in Florida waters, with an average 75 killed by boats every year. Manatees' ability to avoid approaching boats, scientists theorize, may depend on how well they are able to localize sounds from approaching boats.
Working at the Mote Marine Laboratory in Sarasota, Fla., the researchers found manatees were able to follow signals changing at rates up to 1,400 cycles per second, with peaks in their response at 150 and 600 Hz.
"This is remarkably 10 times faster than that of humans, but only half that of dolphins," explained Mann. "This rapid temporal processing could be an adaptation for localizing sounds underwater."
The study appeared in a recent issue of the Journal of Comparative Physiology.
