Which Animals Can Regenerate Body Parts?

The science world was abuzz this week with news of sea slugs regenerating their entire bodies. Scientists discovered if they decapitated (cut the head off) a certain species of sea slug, the head kept going about as if everything were normal. Then, the slug head slowly grew its entire body back!

After further investigation, the scientists found that these slugs, Elysia marginata, would self-decapitate if they were infested with parasites and then grow back a parasite-free body.

That sounds like something out of a science fiction novel (maybe one by Octavia Butler). It seems like the human equivalent of cutting off your own head if you catch COVID-19 and then growing back a healthy body. Hopefully, that healthy body will remember all the time I spent on my treadmill this winter.

When I investigated a little further, I found other examples of animals regrowing parts of their bodies too.

There are some worms that, when you cut them down the middle, will regenerate into two fully grown worms! Scientists have actually figured out which sequence of DNA actually let worms do that.

Some worms can actually detect light after they’ve been decapitated, but before they’ve grown back eyes!

Lastly, starfish can regrow arms, which they can shed on purpose to escape predators.

Not only is this stuff really cool, it could potentially lead to future developments in medicine.

Sources:

https://www.nytimes.com/2021/03/08/science/decapitated-sea-slugs.html

https://www.nytimes.com/2019/03/20/science/worm-regeneration.html?action=click&module=RelatedLinks&pgtype=Article

https://www.nytimes.com/2017/07/31/science/planarian-flatworm-decapitation-light-detection.html?action=click&module=RelatedLinks&pgtype=Article

https://en.wikipedia.org/wiki/Starfish