Today is World Aquatic Animal day, so here are some facts about an aquatic animal I’ve not covered yet – dugongs.
Dugongs belong to the order Sirenia, which also includes their cousins, the Manatees. Dugong dungon is the only living dugon in the order. The only other true species of dugong, Hydrodamalis gigas, was hunted to extinction in 1767, just 36 years after its discovery. Dugongs are also related to Elephants.
There is a 5,000-year-old wall painting of a dugong, apparently drawn by Neolithic peoples, in Tambun Cave, Malaysia.
The word "dugong" derives from the Visayan language. It doesn’t, as is commonly thought, mean "lady of the sea". Other common names include "sea cow", "sea pig", and "sea camel".
They are strictly vegetarian, the only completely herbivorous marine mammal on the planet. Their diet consists mainly of seagrass which they tear up by the roots using their lips, leaving a bare trail behind them. Their grazing habits are one reason for them being known as sea cows. An adult dugong will eat up to 30 kilograms of seagrass a day, and if seagrass is scarce, they’ll eat algae.
Mature males and older females have tusks. It’s possible to tell by the rings on a dugong’s tusks how old it is. Dugongs can live up to 70 years.
They are sociable animals and live in groups of up to 200. They communicate with each other using chirps, whistles, barks and other sounds that echo underwater.
They can mate at any time of year. A group of males will pursue a female: the “following phase”. This is followed by the “fighting phase”, which is what it says on the tin: the males fight each other for the female and the female may fight off unwanted males as well. Finally there is the “mounting stage” which is also what it says on the tin, where several of the males will get lucky. Female dugongs only produce one calf every 2.5 – 7 years and are pregnant for 13 – 14 months.
There is a myth in some parts of the world that dugongs were once human women, and that they cry when they are butchered or beached. It is therefore bad luck to kill one, so they don’t get hunted for food in these areas. In other places, however, dugong meat is said to have aphrodisiac properties and is considered a luxury food. In some places, the tusks were used as sword handles.
They have been hunted, or trapped in fishing nets enough to make them endangered. Australia has created a number of dugong protection parks where it is illegal to hunt them, even for Aboriginal Peoples.
It is tricky and expensive to keep dugongs in captivity, because the seagrass that they eat is hard to grow in an aquarium.
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