Head Over Hearts

Lizards shedding and re-growing their tails are probably the best-known examples of impressive regeneration in animals, but other species take autotomy, the voluntary loss of body parts, to an extraordinary extreme. Sea slugs Elysia cf. marginata (shown here) and E. atroviridis can separate their heads from the rest of their body, including their heart, and not only survive, but regenerate a complete body from the head section: feeding within hours, regrowing a heart within a week, and fully regenerating around three weeks after the break. Their diet may hold the key to surviving without major internal organs, as the sea slugs perform kleptoplasty, taking up chloroplasts from the algae they eat into their own tissues, to provide them with energy through photosynthesis. Why they undergo this traumatic process is still unclear, but it could be a means of shedding internal parasites – a radical response that reveals new champions of regeneration.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

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• Video by Sayaka Mitoh
• Nara Women’s University, Kitauoya-nishi, Nara, Japan
• Video copyright held by the original authors
• Research by Sayaka Mitoh and Yoichi Yusa published in Current Biology, March 2021