There are seven types of sea turtles of which six are endangered. Sea turtles are some of the oldest creatures on Earth, dating back 220 million years. They can be found in all oceans of the world except for the polar regions.
Sea turtles differ from land turtles in that they cannot hide inside their shells. Not being able to hide their head, arms and legs makes them vulnerable targets for predators. The only time sea turtles leave the ocean is during nesting season. For this reason, only the females go onto the beach and do so long enough to lay their eggs. Females return to the beaches where they were born to nest and still remember how to get there after decades. Baby sea turtles hatch at night and use the moonlight to guide them to the water.
Sea turtles can travel great distances in the ocean but still need air to breathe, so they must come to the surface of the water periodically to fill their lungs. Depending on the species, sea turtles can weigh anywhere from 80 pounds like the small Kemp's Ridley to 1,000 pounds like the large leatherback. Sea turtles can live to be 70 or 80 years old.