Many lizards have developed a defense mechanism called "autotomy," or, more simply, they are able to drop their tail when they are threatened by a predator. These lizards' tails often have aspects that draw a predator's attention, such as being brightly colored, having sharply contrasting colors or patterns, or moving when the lizard is otherwise still. Though this is a natural reaction to what the lizard perceives as a threatening situation, it is still stressful for the lizard, and there are things that you should do to facilitate proper healing and, for some species, regrowth.