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All creatures have tricks to heal themselves. If you get a cut, your skin will form a scar. Starfish and salamanders can regrow lost limbs. And it turns out that some jellyfish have a really unusual way of repairing an injury. NPR's Nell Greenfieldboyce tells us scientists were recently shocked to discover this.
NELL GREENFIELDBOYCE, BYLINE: Moon jellyfish are strange, little creatures. A couple of years ago, Michael Abrams, at the California Institute of Technology, began growing them in the lab.
MICHAEL ABRAMS: We started doing kind of old-school experiments where you just sort of cut off pieces and see what happens.
GREENFIELDBOYCE: He says each young jellyfish is tiny and looks like a snowflake, with eight arms and a mouth in the center. Abrams tried chopping them in half with a razor blade.
ABRAMS: If you imagine cutting them in half, that means you've now got four arms on one side and no arms on the other side.
GREENFIELDBOYCE: He thought the lost limbs might regenerate, but no. Instead, over a couple of days, the remaining limbs moved around the body until the little jellyfish was once again symmetrical.
ABRAMS: Rather than four arms on one side, you had sort of an X shape - like a cross.
GREENFIELDBOYCE: In fact, no matter how many arms he cut off, these little jellies would rearrange what was left to re-create a symmetrical pattern.
ABRAMS: We were not expecting to see that.
GREENFIELDBOYCE: His adviser, Lea Goentoro, was intrigued.
LEA GOENTORO: It could be a really different strategy of surviving from injuries, so I just thought, well, we need to look at this a bit more.
GREENFIELDBOYCE: The team did a bunch of studies. They're described in the Proceedings of the National Academy of Sciences. What they learned is that the jellyfish get healed by swimming. As a wounded jellyfish struggles to move through the water with its remaining limbs, its muscles contract and relax. This creates forces that push on the body's elastic, jelly-like material, reshaping it until the limbs are once again evenly spaced.
GOENTORO: It's that propulsion machinery itself that drives its own repair.
GREENFIELDBOYCE: The researchers say this idea could prove useful for designing future materials or technologies that would fix themselves, not by replacing a part, but by simply rearranging what's left. Nell Greenfieldboyce, NPR News.
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