Autotomy is the act of casting off a body part in order to
escape (usually from the grasp of a predator). For
example, a spider can lose an arm and lizard may cast
its tail off if it is trying to escape from something that is
hunting it and has caught it by the tail. The nerves in the
tail temporarily remain active and cause it to continue
moving which distracts the predator from the escaping
Autotomy in a lizard tail.
FEATURED BOOK: Integrated Principles of Zoology

Some non-human animals that engage in autotomy can regenerate the body part later
(e.g. can take weeks). The regenerated body part will not be identical in structure or
appearance. For example, the color will be different and cartilage will replace bone.
Bleeding in the tail area is decreased by a sphincter that closes around the area. A
sphincter is a muscle that forms a circle around a tube, natural opening, or duct in the
body. Some male animals (e.g., honey bees, octopus) cast off the organ they use in

Although autotomy is typically used to describe instances where self-amputation occurs
in non-human animals, humans have also been known to engage in autotomy as well. An
example would be self amputation of a limb when the limb is trapped and there is no
apparent chance of help arriving. Autotomy comes from the Greek word "autos" meaning
"self," and the Greek word "tome" meaning "cutting." Put the words together and you have
"self cutting."                                                                                                                                                                                                                                                              
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