Autotomy

Autotomy (from the Greek autos-self and tome- cutting, separation), the ability of certain animals to reflexively and spontaneously discard part of their body upon external touch. This ability developed in the process of the struggle for existence and has a very diverse character. Autotomy is closely connected with a special reflex; thus, in lizards, the tail breaks off even with a light touch, at which certain groups of muscles are torn; however, after destruction of the spinal cord in the lumbar region, the tail does not break off. Autotomy is developed in very diverse groups of animals: the oligochaete worm (Lumbriculus) breaks into a series of small pieces; the octopus (Octopus) discards its tentacles; holothurians eject all their internal organs, which then grow back, etc. As a defensive reaction, Autotomy is especially strongly developed in crabs. In the latter, special so-called breaking joints exist on their legs, along which the break occurs; at this place, the cuticle is not impregnated with lime. In crabs, there is also a special muscle that produces the break, and at the break site there is a special partition that prevents severe bleeding. In decapitated crabs, the ability for Autotomy is preserved, but upon destruction of the abdominal nerve nodes, it disappears. Organs lost during Autotomy subsequently regenerate.