What marine mammal has fingernails?


The x-ray of a manatee flipper reveals a bone structure much like a human hand. In fact, other than the longer digits, an x-ray of a human hand in a glove would look very similar. Manatees have this bone structure because their flippers were once limbs billions of years ago when these animals walked on land like their distant cousin, the elephant.

Either the West African manatee or the West Indian manatee is correct. All manatees are ancient relatives of elephants and other land mammals. Like their cousins the dugong and the Amazonian manatee, the West African manatee and West Indian manatee actually have vestigial fingers inside of their flipper. An x-ray of a manatee’s flipper looks oddly similar to what a human hand in a glove would look like in an x-ray.

The West African and West Indian manatees both have three or four fingernails on each flipper, the same number of fingernails an elephant has on each foot. The reason all manatees have five “fingers” inside of their flipper and two species have fingernails is because they used to walk on land and had limbs like other four-legged animals.

The exact purpose that fingernails serve isn’t clear. When manatees feed on vegetation in shallow areas, they will use their flippers in a walking motion, much like their slow-moving elephant cousins. Researchers speculate that the fingernails assist them in walking to find food.