Manatees are large, fully aquatic, mammals. Manatees are mostly herbivorous too. Manatees are endangered species due to hunters, and other natural living things such as Red tide algae. The red tide algae was responsible for killing over 200 manatees. ” The Red Tide algae bloom blamed for killing more than 200 manatees this year appears to have finally dissipated, according to state wildlife officials”. I Predict that manatees will live for many more years, because people will wake up to the madness.