arm and a leg

5 animals that can regrow limbs

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The human body is a marvel of evolution, but there’s one thing salamanders, starfish, worms, octopuses, and a few others have that’s out-with our powers.

They can regenerate lost limbs.

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Tiny tube-shaped invertebrates called hydra, for example, can be cut in half, and each tiny half will become a new hydra.

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They do this by reorganizing cells near the wound to create whatever body part they need.

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More complex animals like axolotls, for example, regenerate limbs by growing a structure called a blastema.

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The cells inside the blastema can then form tissues, cartilage, and bone for the new limb.

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When threatened (or when mating), an octopus might detach its own arm and swim away. It then regrows the arm using undifferentiated stem cells that then specialize into the various cell types needed to build a new arm.

Anna Valujskaâ / EyeEm/EyeEm/Getty Images

Starfish take limb regeneration a step further — they not only grow a new arm when they need to, but they can grow a whole new body from a severed arm alone.

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Lizards can regrow their tails using special, undifferentiated cells, but the new tails might be stumpier than the original.

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And it’s not just small reptiles that can regrow their tails — scientists just discovered baby alligators can do it, too.

Read more science and nature stories here.

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