Why do many lizards shed their tails when threatened?

Tail shedding, or autotomy, is a survival strategy in which the tail breaks at specialized fracture planes in the vertebrae or connective tissues. The detached tail may wriggle for several minutes, drawing a predator's attention away from the lizard itself. Losing the tail can be costly because it stores fat and helps with balance, but escaping alive is often more important. Many species can regenerate a replacement tail, although the new one is usually not identical to the original. This trait is common in several lizard groups around the world.