The dugong 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, was hunted to extinction in the 18th century. The word “dugong” derives from the Tagalog term dugong which was in turn adopted from the Malay duyung, both meaning “lady of the sea”. Other common local names include “sea cow”, “sea pig” and “sea camel.
The dugong has a tubular shaped 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. The dugong is heavily dependent on seagrasses for subsistence and is thus restricted to the coastal habitats where they grow, with the largest dugong concentrations typically occurring in wide, shallow, protected areas such as bays, mangrove channels and the lee sides of large inshore islands. Its snout is sharply downturned, an adaptation for grazing and uprooting benthic seagrasses.
Dugong Range – Its range 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 in Western Australia and Moreton Bay in Queensland. Australia is home to the largest population.
The Great Barrier Reef provides important feeding areas for the species; this reef area houses a stable population of around 10,000, although the population concentration has shifted over time. Large bays facing north on the Queensland coast provide significant habitats for dugong, with the southernmost of these being Hervey Bay and Moreton Bay. The population of Shark Bay is thought to be stable with over 10,000 dugongs. Large numbers of dugongs live to the north of the Northern Territory, with a population of over 20,000 in the Gulf of Carpentaria alone. A population of over 25,000 exists in the Torres Strait, although there is significant migration between the strait and the waters of New Guinea.