Animals that can bite hard may use this as a defense mechanism. Both of these turtles are noted for being very defensive on land, and will readily bite perceived predators. Turtle species that are unable to fully withdraw their head into their shell, such as both snapping turtle species, will readily bite in defense. Both species are benign when encountered in the water, where they needn't fear any predators; it is only on land where they are out of their element and feel vulnerable.