Question: Why can't we grow limbs or fingers back, like starfish or lizards can (some lizards do it with their tails)? Wouldn't it have been a useful evolutionary trait?

  1. Do you know that we CAN regenerate limbs….but only before we’re born. Human embryos have some regeneration capability. But this disappears long before we’re born, unfortunately. There are scientists that are working on ways to tell the body to send regeneration cells instead of scar forming cells to the site of an injury. We’re not quite there yet….

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  2. GREAT question.
    Salamanders, starfish and lizards are able to regenerate and grow an entire limb. But their physiology is different from ours. When we get a cut or lose a finger/limb, our body makes what we call scar tissue. But this doesn’t happen in these other animals. Our cells (stem cells) also have less potential to make all of the cell types that are in a finger/ limb (bone, cartilage, blood vessels, nerves etc. a lot of different cell types)

    You mention “useful evolutionary traits”. That’s really great that you think of things from that angle. Any animal that can regenerate would have a huge advantage for sure. But “evolution” has brought humans to the top of the food tree, where we don’t need to worry about a great number of animals hunting and eating us.
    On this note, some lizards have developed a survival mechanism where they detach their tail if they’re caught, so they can run away and survive.

    Hope that explain some things 😉

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  3. You are right, pommypomtom.
    It would have been a great evolutionary trait.

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