Australian.Geographic_2014_01-02

January–February 2014 57

Hydrodamalis gigas

Unlike its surviving relatives, the man-

atees and dugong, this slow-moving

herbivorous mammal was not a tropical

species but a cold- and temperate-water

specialist. Hunted to extinction in the

1700s, it was by far the biggest of the

sirenians, possibly reaching lengths of

more than 8m.

Steller’s sea cow

Trichechus senegalensis

This is the least studied of all the sirenians. It’s

found in marine and freshwater habitats in

equatorial waters along the west coast of Africa.

Similar to other manatees, it’s known to eat a

wide variety of aquatic vegetation and is even

able to eat the tough waxy leaves of mangroves.

African manatee

Dugong dugon

Dugongs are born with smooth pale skin but all

eventually develop scars – the result of the tusks of

adult males. Because they often fight each other,

male dugongs have scarring from the middle

of their back down to their tails. Males also use

their tusks for leverage during mating, so females

become more marked around the head and neck.

Dugong

January–February 2014 57

AMAZONIAN

DUGONG

AFRICAN

WEST INDIAN

STELLER’S SEA COW

Si ze

matters

ILLUSTRATIONS BY DAN SHERIDAN