"Back in 1902, a scientist examining the smooth, grapefruit-size brain of a manatee remarked that the organ's unwrinkled surface resembled that of the brain of an idiot.
Ever since then, manatees have generally been considered incapable of doing anything more complicated than chewing sea grass.
But Hugh, a manatee in a tank at a Florida marine laboratory, doesn't seem like a dimwit. When a buzzer sounds, the speed bump-shaped mammal slowly flips his 1,300 pounds and aims a whiskered snout toward one of eight loudspeakers lowered into the water. Nosing the correct speaker earns him treats.
Hugh is no manatee prodigy. Such sensory experiments, along with other recent studies, are revealing that sea cows aren't so stupid after all.
Researchers contend that if the plant-eating beasts seem slow-witted, it is because they faced no threats to their survival before the advent of boat propellers.
"They're not under any selection pressure to evolve the rapid-type behavior we've associated with hawks, a predator, or antelopes, a prey. They look like very contented animals that don't have very much to do all day," said Roger Reep, a neuroscientist at the University of Florida's College of Veterinary Medicine."