manatee
man·a·tee /ˈmænətiː/ noun [countableC] 
a large sea animal with flippers and a large flat tail, which eats plants 海牛
a large sea animal with flippers and a large flat tail, which eats plants 海牛Examples from the Corpus
manatee• But at that time, biologists also saw sick, disoriented manatees acting strangely by curling their lips and arching their backs.• She has to get manatees picked up and taken to the researchers quickly, before tissue samples deteriorate.• Although sale of manatee meat is against the law, it is still to be found in markets.
(1500-1600) Spanish manatí, from a Cariban language