• Question: Why do worms keep moving when you cut them in half (not that I ever have done)?

    Asked by scientist101 to Edd, Jess, Zara on 23 Jun 2011.
    • Photo: Edward Codling

      Edward Codling answered on 23 Jun 2011:

      I’m glad you haven’t been cutting up worms – that would be cruel! 😉

      If you cut a worm in half then part of it will survive – the ‘saddle’ (the band around its middle) is needed, so the half with this bit can survive. The other half will die although it may continue to wriggle for a while once it has been cut off.
      http://www.bbc.co.uk/gardening/gardening_with_children/didyouknow_worms.shtml

      This is a bit similar to some lizards and amphibians who can regrow a leg or tail if it is cut off. They couldn’t regrow a head or a body though!

    • Photo: Zara Gladman

      Zara Gladman answered on 23 Jun 2011:

      Hi scientist101! 🙂

      Edd has beaten me to the answer! I actually tried this when I was a really young kid (nasty I know! I was 3, please forgive me), and it did work. But only the half with the saddle (which the worm needs for reproduction) survives. The other half keeps moving because the nerve endings take a while to stop firing.

      Have you heard the phrase ‘run around like a headless chicken’? I guess it’s a similar idea! Electrical energy in the nerves allows the chicken to keep running around the farmyard after it has been beheaded. Creepy!

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