Dugong

The dugong, or sea cow, is a large marine mammal with a torpedo-shaped body, no dorsal fin and no hind limbs. Its front limbs are short, paddle-like flippers, and it swims with a notched, dolphin-like tail fluke, which tells it apart from the manatees. The snout is sharply downturned, an adaptation for feeding on seagrass on the seabed, and the molar teeth are simple and peg-like. It is the only living member of its family and the only strictly marine plant-eating mammal (Wikipedia, general species account).

Across its range the dugong depends largely on seagrass communities, which restricts it to warm, shallow coastal waters, with the largest concentrations typically in wide, sheltered areas such as bays, mangrove channels and the waters of large inshore islands. It has been hunted for thousands of years for meat and oil, and today fishing-related deaths, habitat degradation and hunting drive declines. Its long lifespan of 70 years or more and slow reproduction make it especially vulnerable, and many populations are now fragmented and small (Wikipedia, general species account).