Scientists in Japan have discovered that this species of sea slug can decapitate itself and then regrow an entirely new body, complete with a beating heart and other vital organs.

The process, from shedding all of itself below the neck to regrowing a new body, took less than a month, in an extreme example of a process known as autotomy.

Sayaka Mitoh, of Nara Women’s University, said: “We were surprised to see the head moving just after autotomy.”

As reported in the journal Current Biology, Mitoh and colleague Yoichi Yusa wrote how in their studies of the life history of the sea slugs, they spotted something odd.

Three of the younger lab-raised sea slugs, and one wild specimen being reared, “autotomized at their neck position” leaving behind a body with its heart, kidney, intestine and most of the reproductive organs.

While the bodies didn’t survive very long (from days to months before decomposing), the decapitated heads started feeding on algae within hours and healed the “wound” within a day.

Mitoh and Yusa noticed a groove on the neck of the sea slugs. They tied some nylon around it to stimulate the mollusk’s trick, and some of those specimens dutifully performed.

The scientists think the sea slugs may have developed the technique as a way of getting rid of a parasite in their bodies.

Another key part of the trick is finding a way to get energy when you don’t have a digestive system.

The scientists think the sea slugs are using the energy from the photosynthesis occurring in cells that they’ve gained from algae they’ve eaten.

According to