This image shows the head and body of an Elysia cf. marginata sea snail one day after separation.
Sayaka Mitoh
Most animals cannot lose their bodies and still survive. Two species of sacoglossan sea snails are not most animals. A team of researchers observed sea snails cutting off their own heads and then resuscitating their bodies with hearts and other internal organs. The action of shedding a body part is called autotomy. It is what do lizards do when they lose a tail for self-preservation.
Losing an entire body is far more dramatic than losing a tail. “We thought it would soon die without a heart and other vital organs, but we were again surprised to discover that it regenerates the whole body,” Sayaka Mitoh of Nara Women’s University in Japan said Monday in a statement. Cell Press said. Mitoh is the lead author of a study on marine snails published in the current journal Cell Press Journal.
The severed sea snail heads could feed within hours.
Sayaka Mitoh
The reviving sea snails were younger individuals. It took about a week to regrow the heart, and they completely recovered their bodies within three weeks. According to the researchers, there may be ‘stem-like cells’ where the neck is cut that allows regrowth.
The younger sea snail heads were able to move and feed algae shortly after separation, which apparently was the key to their survival. Older snail heads did not feed.
The unusual animals take an indication of plants. “The sea snails involved were unique in that they incorporated chloroplasts of algae they ate into their own bodies, a habit known as kleptoplasty,” Cell Press said. “It gives the animals the ability to promote their bodies through photosynthesis.”
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The ability to regrow a body is not unheard of. Some types of jellyfish can regenerate after an injury. However, the self-decapitation part of the sea snail process adds to the mystery. According to the researchers, the action may be a way to get rid of internal parasites, but the impulse is unclear.
The surprising process of body regeneration is already giving scientists ideas for further studies. Mitoh said, “Since the body’s body is regularly active for months, we can study the mechanism and functions of kleptoplasty using living organs, tissues or even cells.”