au·tot·o·my /ɔˈtɑtəmi/
  自割
  au·tot·o·my /ɔˈtɑtəmɪ/ 名詞
  自切(動),自殘
  autotomy
       n : 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