Although they prefer water no deeper than 10 metres / 33 feet which is in some ways safer for them, they can dive to depths of about 40 metres / 131 feet. They spend much of their time searching for their favourite food which is sea-grass.
Dugongs need air to breathe so in between foraging they rise to the surface of the water. Underwater they can hold their breath for more than 5 minutes.
Because they are timid, and do not approach humans, knowledge of their behaviour is limited.
Dugongs "talk" to each other using a range of sounds such as barks and whistles or chirps with different tones and modulations that reverberate underwater. Visual communication is utilised less due to poor eyesight.
Collisions with fishing boats and drowning whilst caught in fishing nets and lines plus the degeneration of their food sources are all contributing factors. Dugongs are totally dependent on sea-grass and will travel extensive distances in search of it. Pollution in the seas and environmental damage to reef resources now adds to their vulnerable status.
Dugongs can live for many years (as much as 70) but their limited birth rate exacerbates their situation. They do not reach puberty until 10 years old and females reproduce only one calf at a time with rest periods of about 5 years between births. The gestation period is more than a year long for each pregnancy and mothers devote a lot of time to rearing their young. A female cannot expect to produce more than 12 calves in her entire life.
Mozambique's beautiful underwater world is a best kept secret. Families of Dugongs are regularly seen in the crystal clear waters of the Bazaruto and Quirimbas Archipelagos. An aerial census takes place annually to ascertain trends in the population numbers in this area, as they may be the last of their kind along the whole East African coast.
Dugongs can be spotted in shallow coastal waters where sea-grass is abundant and they can shelter from heavy storms and waves. Dugongs are easy to identify as their muzzle is large and fleshy, they have paddle-shaped flippers but no dorsal fin and their tale is similar to a Whale.
They have a good sense of smell and very sensitive bristles on their snout to help them feel their way around, which makes up for a lack of sharp vision.