Seven species of sea turtles inhabit the world's oceans. These air-breathing reptiles have survived virtually unchanged for 200 million years. Sea turtles are unique among marine animals because they must return to land to reproduce; they lay their eggs on tropical, sandy shores. These amazing animals have outlived the dinosaurs, yet now they are threatened with extinction due to the actions of humans. Nowhere are the threats to their survival more evident than on Florida's beaches.