Dugong  (Dugong dugon)

Dugongs are usually seen as solitary individuals or in a group of two, although larger groups of several hundred individuals have often been recorded. The most stable and long-lasting groups appear to be mother and calf pairs. The single calf, born after a gestation period of around 13 to 14 months, measures over a metre in length at birth, and suckles from the female for around 18 months (2) (3) (7) (11). Dugongs can be extremely long-lived, reaching ages of 70 years or more (2) (3) (7).

Both dugongs and manatees have a low metabolic rate, allowing them to exist on a herbivorous diet, and consequently they usually move relatively slowly. They have pectoral mammary glands reminiscent of human breasts. These features, and their nursing behaviour, may have caused sailors to liken them to mermaids or sirens; hence the order name of 'Sirenia' (2) (3). Although most seagrass beds upon which dugongs feed occur at depths of 1 to 5 metres (2), they are known to feed at depths of up to 33 metres (8). Using the flexible upper lip to rip out whole plants, dugongs leave characteristic furrows known as 'feeding trails' on the sea floor (3) (6). Dugongs are more closely related to elephants than the cows after which they are named, and have a particularly long large intestine to aid digestion (3) (11).