Dugongs are large marine mammals inhabiting warm ocean waters surrounding Australia and Indonesia. Most dugongs are concentrated around northern Australia, while they are also found throughout the Indo-Pacific tropics.
The legends of mermaids are believed to have originated when sailors viewed dugongs and manatees from a distance and mistakenly thought they were half-fish, half-human.
The dugong looks very similar to a manatee, and is very closely related, but the two are different species. Dugongs are smaller than manatees, about the size of a large cow. Tails of dugongs are usually forked like that of a shark, while the tails of manatees are broad and flat and look more flipper-like than fin-like. Dugongs are also closely related to elephants. Dugongs evolved millions of years ago when an elephant-like animal entered the water.
Male dugongs develop tusks between the ages of 12 and 15 years old. Females do not usually grow visible tusks.
Dugongs are strictly herbivorous animals, often called “cows of the sea”. Dugongs graze on aquatic plants and sea grasses growing in warm, shallow waters. Dugongs shake their heads to remove sand from their food. Since dugongs consume large amounts of sea plants, they frequently leave trails of bare sand and uprooted sea grass behind them.
Being mammals, dugongs needs to surface every six minutes to breathe atmospheric oxygen. They can also breathe by standing on their tails with their heads above the water.
Dugongs live on their own, in pairs or in communities. Dugongs use a variety of sounds to communicate with each other, including barks, chirp-squeaks and trills.
Female dugongs give birth to one baby approximately every five years. Baby dugongs are born underwater in the tropical shallows. Baby dugongs can swim immediately and surface the water to take their first breath. Mother and baby dugongs have a strong bond. Baby dugongs sometimes ride on their mother's back. Baby dugongs stay near their mothers until they are about 2 years old. Dugong calves reach full size at about 15 years old.
Dugongs live to be about 70 years old.
The main predators of dugongs are sharks, killer whales and crocodiles.
THREATS TO DUGONGS
Dugong populations have decreased dramatically due to chemical pollution, hunting, the commercial fishing industry and coastal development. While the dugong is now protected by law, their populations remain low due to slow reproduction. Dugongs are considered vulnerable to extinction due to hunting, pollution, boat collisions and getting caught in fishing nets.