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autotomy au·tot·o·my (ô-tŏt'ə-mē)
The spontaneous casting off of a body part, especially of an invertebrate, when injured or under attack.
the ability of certain animals to release part of the body that has been grasped by an external agent. A notable example is found among lizards that break off the tail when it is seized by a predator. The phenomenon is found also among certain worms, salamanders, and spiders. The cast-off part is sometimes regenerated