Aquatic mammals are a group of animals that live in the water and include seals, otters, manatees, and porpoises. Seals are carnivorous marine mammals with five letters in their name. Otters are semi-aquatic mammals with webbed feet and thick fur, and they have six letters in their name. Manatees are large, slow-moving aquatic mammals with eight letters in their name. Porpoises are small toothed whales with nine letters in their name.