DUGONGS - The Ladies of the Sea
Dugongs name comes from the Tagalog name “dugong”, which originates from the Malay term “duyung”, which means “lady of the sea”. Maybe it’s because of their gentle look and the graceful way these animals swim. Maybe it’s because some believe that dugongs served as inspiration for ancient seafaring tales of sirens and mermaids. Dugongs, also known as "sea cows", belong to order Sirenia (from those sirens as you see). They’re a tropical to subtropical species that can be found in warm coastal waters of Red Sea, East Africa, Australia, Japan and Philippines.
Dugongs are large marine animals that can reach length of 3,35 m and weight of up 1000 kg. They’re actually the only completely marine mammals. They have a flat tail and flippers like a whale, but their closest land relative is - you will be surprised - the elephant. Dugongs have evolved 50 to 60 million years ago, when an elephant-like creature entered the water. Just imagine that:)
These slow-moving animals are true vegetarians eating only seagrass. They have a large mouth with upper lip designed for bristling of seagrass and can eat up to 44 kg of seaweed daily. Before swallowing of the seagrass, dugongs will shake their head to eliminate sand from the food.
AMAZING FACTS ABOUT DUGONGS
Dugongs hear the seagrass grow
Dugongs don't have the best eyesight, but they have excellent hearing. Much like dolphins, when they are in the group they communicate using barks, chirps, whistles, squeaks, trills and other sounds that echo underwater.
Dugongs can hold their breath for 6 minutes
Dugongs breathe using the lungs. They need to reach the surface of the water every six minutes to breathe atmospheric oxygen through their nostrils. When these mammals are located in the shallow water, they breathe by “standing” on their tail with their heads above the water's surface. Another interesting fact is that they can dive up to 33 meters to feed.
Female dugongs are great mothers
Female dugongs give birth only a few times during their life (every 3 to 7 years) and have one calf after a yearlong pregnancy. They are great mothers which invest considerable parental care in their young. They help their little ones reach the surface and take its first breath. Young dugongs usually stay close to their mothers, suckling from her until the age of 18 months. These cute calves really enjoy the stay with their mothers and sometimes catch a ride on mother’s broad back. They only leave their mother once they have matured.
Dugongs can live up to 70 years
Dugong can survive up to 70 years or more in protected habitats with enough food sources. And what is interesting, you can estimate a dugong's age by how many rings it has on its tusks, just like a tree! Male dugongs grow tusks when they reach maturity and female get tusks when they get older.
Dugongs move like a lady
Dugongs have very dense and heavy bones which hold them submerged under water. Their lungs are positioned along the back and they keep dugongs in horizontal position during swimming. People, who were lucky to observe dugongs, say that they gain forward motion with their tail fin. Each powerful downward beat provides a forward thrust. This course of motion appears wave-like, flowing and graceful, very powerful, and while swimming the animal appears astonishingly streamlined. For a change of direction he turns his head and shoulders into the desired direction and gains additional steering with his forearms.
Dugongs have one partner for life
Unlike manatees, which are devout polygamists (have up to several female partners), dugongs are believed to stick to just the one partner, which they live with for life. But, while steller's sea cows are thought to have been completely monogamous, dugongs may exhibit reproductive behavior like lekking. Some believe that dugongs are so called serial monogamists, that stick with one partner every breeding season.
Dugongs have very few natural predators thanks to their massive size, tough skin, dense bone structure, and rapidly clotting blood. Sharks, crocodiles, and killer whales, however, feed on juvenile dugongs. But much bigger threat to their survival is connected with negative human activity. Coastal development, industrial activities that cause water pollution, shark nets or natural disasters as cyclones wipe out the seagrass beds, that are dugongs sole source of food. If there is not enough seagrass to eat then the dugongs don't breed normally. That’s why the conservation of their shallow water marine habitat is extremely important.
Dugongs are also easy target for coastal hunters, and they were hunted for thousands of years for their meat, oil, skin, bones, and teeth. They are protected by law today, but their population is still at low number because of the slow reproduction.
The dugongs current distribution is fragmented and they listed as vulnerable and close to extinction. Their number is still decreasing. In the last 30 years it is estimated that dugong populations has declined 90%.
You can help Dugongs by living the way that doesn’t hurt nature and animals. By learning, studying, spreading the message, by being curious and informed or by supporting organizations, that help these amazing animals, that are dying because of us, humans.
Sources and more info: