For at least two species of sea slug, decapitation is no big deal. After purposefully severing its head, a sacoglossan sea slug can regrow its entire body, heart and all. Scientists observed the phenomenon -- detailed Monday in the journal Current Biology -- while studying the development of the marine invertebrates, from eggs to adult sea slugs. In the lab, researchers noticed the head of a sacoglossan sea slug moving around without its body. "We were surprised to see the head moving just after autotomy," lead author Sayaka Mitoh, a doctoral candidate at Nara Women's University in Japan, said in...