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Dugong swimming © Mike Parry/Minden Pictures

Dugongs are preyed on by sharks, killer whales and crocodiles, but their main threat is humans.

A Water-based Distant Relative of the Elephant

Similar to manatees, dugongs are large aquatic mammals, growing as large as 13 feet and 2,200 pounds. Like their distant relative, the elephant, males have tusks emerging from their gums, though they are not visible when the mouth is closed. Dugongs occupy a large range in which there are no similar species, arcing along the coast of east Africa, across south Asia and down to Australia. However, populations are not continuous, reflecting their loss of habitat. They typically inhabit shallow waters with an abundance of the sea grasses on which they graze, though they have been observed in water as deep as 75 feet. 

Though dugongs are slow moving, averaging a swimming speed of 6 miles per hour, they can cover 16 miles a day, sometimes hundreds of miles a year. They usually congregate in small groups of up to six individuals but have been observed in herds as large as several hundred animals. 

Dugongs are preyed upon by sharks, killer whales and crocodiles, but the main threat to the species is humans. While some populations remain abundant, others have been drastically reduced by hunting. Dugong bones found in the United Arab Emigrates indicate that the practice has been in place in excess of 4,000 years. The species is protected in Australia, home of the largest population, estimated around 85,000 individuals.