When you look at a green turtle swimming about, one of the first things you may notice is that they are not green, but rather brownish in color. Their name comes from the green color of the layer of fat lying under their shells. Green turtles can get quite large, the biggest one ever found had a shell five feet long and weighed 871 pounds. Unlike many other species of turtles, green turtles cannot pull their heads back into their shells. Adult sea turtles are vegetarians eating mostly sea grass and algae, but the babies will eat small crabs, sponges and jellyfish. They mate in shallow water near the beach every two to four years and using their flippers, they dig a hole in the sand, where they lay their eggs. They then cover up the eggs with sand and return to the sea. When the eggs hatch the babies make the short but dangerous trip back to the sea. Those that survive the onslaught of predators like seagulls and crabs may live to be 100 years old.