Marine mammals are a group of aquatic animals that live in the ocean and include seals, walruses, whales, and cetaceans. Seals are carnivorous marine mammals with five letters in their name. Walruses are large marine mammals with eight letters in their name that have long tusks and whiskers. Whales are the largest mammals on Earth with six letters in their name and are known for their long migrations. Cetaceans are a group of aquatic mammals with five letters in their name that includes dolphins and porpoises. Sealions are a type of sea lion with eight letters in their name that are known for their playful behavior.