Monkey-chow snack biscuits in hand, Edmund Gerstein coaxes a manatee through an underwater hoop. After multiple attempts, the sea cow finally completes the task alone.
What seems like a simple procedure may one day save the lives of many manatees, giving them the valuable training to avoid colliding with oncoming boats.
Gerstein, the director of marine mammal research and behavior at Florida Atlantic University, says that any animal can learn what risk is and how to avoid it.
“Manatees have the mental capacity to escape from danger,” he says. “Knowing this, my colleagues and I were compelled to look at their hearing.”
Preconceived notions of manatees as unintelligent and too slow to move out of a boat’s path are being dispelled with Gerstein’s research. When startled, notes Gerstein, a manatee can reach swimming speeds of more than 6.4 meters-per-second.
Along with his colleagues, Gerstein had wondered about the possibility that manatees are unaware of the danger.
“We started to toy with the idea that maybe they just can’t hear the boats coming toward them,” he says.
Gerstein then conducted the first ever precisely controlled underwater audiometric study. This test demonstrated what manatees could and could not hear in their environment. In addition, a series of underwater acoustic surveys of differing manatee habits were performed – including boat propeller sounds.
In 1991, experiments began on Stormy and Dundee, two captive-born manatees at the Lowry Park Zoo in Tampa. It took about one year to complete the thousands of trials and tests necessary to determine the proper results. Gerstein described it as a long and arduous process.
Stormy and Dundee were trained to place themselves inside an underwater hoop-shaped listening booth where they would hear sound waves. A waterproof microphone would then record everything that was played. The manatees had to stay in the booth until they saw a light flash. After the flash, the manatees would hit a specific paddle if they heard a sound. They would select a different paddle if no sound was heard.