The attributes of the turtle's shell can vary greatly, from hard and bony to flexible and leathery. Some turtles have shells with bright markings or unusual shapes. Turtles have solid skulls without temporal openings. Instead of teeth, they have horny beaks. The beak of a turtle is adapted for it's primary diet.
Carnivorous species have sharp hooked beaks to grasp and slice animal prey.
Vegetarian turtles and those that eat mollusks have beaks with flat, broad crushing surfaces. Turtles can be found on every continent except Antarctica. They have adapted to a wide range of habitats, including deserts, rainforests, mountains, and rivers. Marine turtles occur in tropical and temperate seas throughout the world. Many of the terrestrial turtles are referred to as tortoises .