It is impossible to tell exactly how old a manatee is when it is alive. After they die, however, their true age can be determined by counting the number of growth rings in their ear bones (much life counting the rings in tree trunks).

The average adult manatee weighs over 1000 pounds (450kg), can measure 13 feet long and has a maximum lifespan of 60 years (even in captivity). Also, the manatee cannot survive, though, in water cooler than 60°F (16°C).

Additionally, manatee’s only ever have approximately 6 teeth per quadrant at any one time; these teeth are very large and are of only one type, hind molars. Their teeth are constantly replaced throughout their lives. New teeth form at the back of the jaw, wear down as they move forward, and eventually fall out. This constant tooth replacement is an adaptation to the manatee’s diet, which often includes abrasive plants that are mixed with sand and is known as hind molar progression or marching molars.