The elephant is considered the manatee's closest living relative.
The pectoral flippers always contain three to four vestigial fingernails that look remarkably like an elephant's.
Furthermore, manatees and elephants, herbivores that eat plants, have a similar tooth structure.
Manatees, like whales, dolphins and seals, are marine mammals. Manatees, however, are unrelated to whales or seals, although manatees do have something of a whale's body and a seal's head.
Instead, manatees along with the dugong, are members of the order called sirenia. At one time sirenia had a dozen members; only four survive today.
Scientists are not sure why sirenian diversity declined. Availability of aquatic vegetation and/or competition with other marine herbivores and climate change may all have had roles.