Definitions for "autotomy"
spontaneous removal or casting off of a body part (as the tail of a lizard or claw or a lobster) especially when the organism is injured or under attack.
The ability of most lizards to lose their tail. This is beneficial in lizards as it aids in escaping a predator. However, it can also be detrimental because the tail is where they store fat and it takes a lot of energy to re-grow (not all lizards can lose their tail, and those that do can only grow them back when the conditions are right).
The ability of certain lower animals, such as lizards and starfish, to cast off injured body parts, such as the tail and, usually, to regenerate new ones (Morris 1992).