 When frightened by a predator, green iguanas will attempt to flee and, if near a body of water, dive into it and swim away.If cornered by a threat, the green iguana will extend and display the dewlap under its neck, stiffen and puff up its body, hiss, and bob its head at the aggressor.If the threat persists, the iguana can lash with its tail, bite and use its claws in defense.