Physical Features and Behavioural Traits of Dugongs
Dugongs are large aquatic mammals which are found in shallow coastal
water. They are mainly herbivorous and belong to Family Dugongidae.
Physical features
The sea cows or dugongs look like sturdy, strong small whales. Dugongs
have broad and powerful horizontal tail, two short and thick ‘pectoral’
fins. The adult dugongs grow about 3 meters and weigh up to 400
kilograms, the females generally outsize the males. The dugongs are born
with light brown colours, which become dark as they grow older. The male
dugongs that are 12 years or older and few very old females have
tusk-like incisors.
Locomotion
The slow swimmers dugongs swim with slow movements of its tail. They
swim by moving their huge spread-like tail in up and down motion. The
average speed of dugongs is generally 10 kilometres per hour and while
moving across short distances or in case of danger, they can cover a
speed of 25 kilometres hour. The reasons for longest movements of the
dugongs are climatic ones like need of warmer water during the winter
months.
Though dugongs live in small groups, herds of hundreds of dugongs are
also found throughout the coastal areas. However, in many countries,
only few specimens of dugongs survive.
 At Moreton Bay in Queensland in Australia, dugongs are known for making
daily trips of 14 to 40 km from the shallow water to the open ocean. The
daily movements of dugongs also depend on tidal amplitude and generally
a large tidal range would mean longer trips. Dugong has the ability to
cross deep ocean trenches sometimes more than 4000 meters deep, thereby,
making very long migrations.
Communication
Dugongs have been heard to make chirps, squeaks and barks especially
during the mating season.
Feeding habits of dugongs
Feeding is an important activity of the dugongs that occur mainly in
shallow waters. The diet of the dugongs is mainly based on Phanerogams
seagrass of the families Potamogetonaceae, Hydrocharitaceae and
Cymodoceaceae. The daily need of the dugong has been estimated about 30
kilograms, generally, these animals feed on whole plants including the
roots.
In fact, the primary feeding mechanism of dugong is uprooting sea-grass
by digging furrows in the seafloor with the help of their snouts. Since
they mainly feed on seagrass, they are also known as ‘cultivation
grazers’.
Dugongs are particular about their diets and they prefer eating high
nutrients and highly digestible seagrasses that includes easily
digestible Halophila, Halodule rhizomesw, which is rich in nitrogen but
lacks in fibres. When they do not get seagrass to eat, dugongs feed on
algae; however, this is not a part of their normal diet. Dugongs live on
fresh water sources for drinking.
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