A tiny animal with an extraordinary ability could teach us how to regenerate lost or damaged body parts. A beheading is lethal for most animals, but not for the flatworm . Chop its head off, and it will simply grow back . The disembodied head, too, can grow itself a whole new body in a matter of days – in fact, almost any fragment of this worm can regenerate an entire body. This remarkable power comes down to stem cells , and new research into flatworm biology shows that we've much more to