Dugongs are classified ar, Sirenia, or Sea Cows, and their nearest terrestrial relative is the elephant. Adult dugongs grow to three metres long and weigh up to 400 kg, Newborns are about 1.2 metres long and weigh up to 30 kg. Dugongs are believed to see about as well as a diver wearing a face mask and seem to have acute hearing. Their eyes, and ears which have no flaps or lobes, are on each side of the head. Their paired nostrils are on the top of the head and have valve-like devices that prevent water entering when they dive.
Dugongs surface for air for a few seconds, every few minutes.
Dugongs appear to have a good memory of place, as satellite tracking shows them returning hundreds of kilometres to specific spots. Because like humans, they live for a long time, they must have few natural predators but they are prey to sharks, crocodiles and killer whales as young animals. If their mothers die, i t is almost impossible to rescue the young, as we can with some other wildlife, because calves suckle for so long and their seagrass diet cannot be grown in captivity. Orphaned calves have not so far been successfully rehabilitated in Australia because of their complex nutritional requirements. They have flippers and tails that resemble those of dolphins, but they lack a dorsal fin.