The Manatees (Trichechus manatus latirostrus) shown here are from Three Sisters Spring, Crystal River, Florida. The warm water springs provide habitats for the manatee populations that migrate here each winter. The shots in blue water were taken inside the springs, the low viz shots in green water in the canal outside the springs.

Manatees are mammals that belong to the order of Sirenea. Which is derived from mermaids. It seems that Columbus  when he spotted manatees along the coastline of America  believed that what he saw were the legendary  mermaids.  

One says that the manatee is closely related to the elephant, with which they  share a common ancestor. There are  definitely some striking resemblances: the  manatee is a vegetarian equipped with flexible muscular lips for ripping of vegetation like the elephants trunk. It has molar teeth that move forward in the mouth. A grey skin covered with sparse hairs, finger nails like the elephant toenails and a spherical  shaped heart.  See album: Manatees