The green sea turtle is known to be the largest hard-shell sea turtle, but has a small head.

 

The species gets its name from the green in its body fat. The turtle's shell actually varies in color.

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The sea turtles are unable to retract their head into their body.

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The green sea turtle has spectacular vision which benefits him as an aquatic organism. The turtles can see many colors. The lense in the sea turtle's eye is spherical and adjusts to underwater reflection, therefore, the turtle is nearsighted when on land.

 

The turtle can only hear very low frequencies of noise because it has no external ears. To make up for this disadvantage, the turtle can detect noise through vibrations of its head, backbone, and shell.

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The nose of the turtle has two external openings. The species pumps water in and out of its nose in order to smell things. The turtle can not breathe underwater and needs to swim up to the suface for oxygen.

 

Green sea turtles find their way in the ocean using wave direction, sunlight, and temperature. In addition, they have an internal magnetic compass. To identify the Earth's magnetic field they use magnetic forces detected by the magnetic crystals in their brains. This special feature helps them find their way around during long distance travel in the ocean.

 

They have paddle-like flippers that help them navigate through the ocean easily.  

 

Compared to the female tutles the males have larger tails and longer claws on the front flippers.