It takes its name from the greenish colour of its fat. It is large and heavy, usually about 0.7-1.0 m in shell length and 90-140 kg in weight. It can attain a maximum length of 1.2 m and weight of 375 kg. Its upper shell is wide and smooth, with an overall brown or slightly greenish colouring. It is found in warm, coastal waters all over the world. Mainly feeding on marine grasses, unlike other sea turtles, it sometimes emerges onto land to bask in the sun.