Dugong

Dugong photo

Photo by Suzanne Challoner.
Dugong, Dugong dugon
Taken at Abu Dabab, Egyptian Red Sea.

Also known as a sea cow, Dugongs feed in the seagrass beds of the Indo-Pacific. They are the only herbivorous, truly marine mammal. (The related manatee spends some of its life in fresh water.)

Being a slow swimmer, you'll find dugongs in sheltered lagoons and bays in warm water such as are found in the Red Sea (eg Marsa Alam), East Africa, the Philippines, and Australia.

Adult dugongs can grow to over 3.5 m (11 ft), and may weigh over 900 kg (2000 lb). Male dugongs begin to grow tusks between the ages of 12 and 15 years. If food is plentiful, the habitat protected, and predation low, dugongs may live more than 70 years.

Dugong dugon

Dugong with golden trevally
Photo by Suzanne Challoner.

They can eat as much as 40 kg (88 lb) of seagrass a day, leaving distinctive troughs in seagrass meadows. Dugongs are natural prey for sharks, killer whales, and crocodiles, but they are most vulnerable to human activities. Hunting has drastically reduced dugong populations in some areas. Dugong habitat is under pressure from coastal development, pollution and other degradation.

You'll find dugongs in sheltered lagoons and bays in warm water such as are found in the Red Sea (eg Marsa Alam), East Africa, the Philippines, and Australia. They have dense, massive bones, which help to keep them submerged. Their lungs lie along their back and act like floats, keeping them horizontal in the water. They can eat as much as 40 kg (88 lb) of seagrass a day, leaving distinctive troughs in seagrass meadows.

Dugongs are thought to use the "lek system" whereby males establish and defend courtship territories in traditional areas where females come only to mate.

Further Reading
The Blue Planet, by Alastair Fothergill, Martha Holmes, Sir David Attenborough, BBC Consumer Publishing, 2001, ISBN 056-33-8498-0