Green sea turtles are gentle giants of the ocean, named not for their shells but for the greenish color of their fat. They have smooth, heart-shaped shells and paddle-like flippers perfect for long-distance swimming. These turtles are herbivores, feeding mostly on seagrass and algae, and they play an important role in maintaining healthy marine ecosystems. Although graceful in water, they are slow and clumsy on land, where they nest on sandy beaches.