The dugong (Dugong dugon) is a large marine mammal which, together with the manatees, is one of four living species of the order Sirenia. It is the only living representative of the once-diverse family Dugongidae; its closest modern relative, Steller's sea cow (Hydrodamalis gigas), was hunted to extinction in the 18th century. It is also the only sirenian in its range, which spans the waters of at least 37 countries throughout the Indo-Pacific, though the majority of dugongs live in the northern waters of Australia between Shark Bay and Moreton Bay. The dugong is the only strictly marine herbivorous mammal, as all species of manatee use fresh water to some degree. Like all modern sirenians, the dugong has a fusiform body with no dorsal fin or hind limbs, instead possessing paddle-like forelimbs used to manoeuvre. It is easily distinguished from the manatees by its fluked, dolphin-like tail, but also possesses a unique skull and teeth.
Contributions by Guy Fuchsia, 184.108.40.206, and Mgiganteus1.