How Do Lizards Survive Danger?

There are only two species of lizard widely acknowledged as being venomous: the gila monster and the beaded lizard. Although some other lizards, such as monitor lizards and iguanas, could also be considered venomous -- scientists at the University of Melbourne in Australia now suggest that venom, rather than bacteria as was originally believed, causes swelling after a bite. The gila monster and beaded lizard use their bite for self-defense. If in danger from a predator, they will deliver a painful chomp that may eventually kill the other animal.

Lizards use color in a variety of ways. Small lizards use it to blend into their surroundings to make themselves invisible to predators. The gila monster and beaded lizard use it as a warning to predators that they're venomous. In nature, bright colors are a warning sign to predators that the animal they’re thinking of eating could be dangerous to them. For this reason, a variety of nonvenomous lizards have evolved to have brightly colored tails. When threatened, they show their tail to fool the predator.

If a lizard can’t escape, hide or trick his predator into thinking he’s poisonous, he can at least make himself look like an unappealing meal. This is how short-horned lizard survives. He has a spiny crest around his throat and a row of spikes on his back. This makes him a very painful meal to swallow -- and is typically enough to put off a would-be predator.

One of the most unusual ways a lizard can defend himself from danger is to shed his tail. When stressed or if captured, the tail simply falls off. This is often enough to confound the predator, who may simply focus on eating the tail, leaving the lizard to escape. No great loss to the lizard, as the tail eventually grows back.

Some lizard species go a step further. For example, when the gecko sheds his tail, the tail continues to move around. This tricks the predator into thinking the tail is a living creature that he has to kill. While the predator deals with the tail, the lizard makes his getaway.

The southern desert horned lizard, when sufficiently threatened, is capable of squirting blood from his eyes. But it’s more than a macabre party trick, the blood is very distasteful to predators, who may drop the lizard and let him escape if any of the blood gets in their mouth.