Some turtles eat only plants, while others eat only animal matter and some eat both plants and meat. Turtles eat abundantly at each meal, but can fast for several weeks without apparent ill effects. The jaws of turtles are a key factor that helps them to chew the variety of foods they love to eat. Green sea turtles, for example, have finely serrated jaws that help them in eating plants, and grass. The snapping turtle will lie on the river bed with its mouth wide open. It has a worm like structure on the floor of its mouth that moves, luring fish straight into its mouth, which the turtle will promptly snap shut. Another important fact about turtle eating habits is that they change their eating habits as they age.
Crocodiles use a very effective technique to catch the prey. As soon as it sights its prey, the crocodile will move silently under water, keeping only its eyes above the surface. When it is close enough, the crocodile rears up and lunges with wide open jaws. Sometimes, the crocodile will wait motionless in one place till the prey comes near enough. It also uses its powerful tail to subdue its prey and drown it -especially if the prey is a large animal.