• Question: Why has a spider got eight legs?

    Asked by anon-22966 to Amy, Sarah, Will on 21 Jun 2012. This question was also asked by 08764654765375437543737dominic.
    • Photo: Sarah Martin

      Sarah Martin answered on 21 Jun 2012:

      Hi Cassie!

      Great question! Robotics research has been used to try to answer your question! Experiments show that six legs easily provide stability. So why two extra?
      It might be that a spider’s “extra” pair of legs is for spinning a web or capturing prey while the other six legs provide stable locomotion.
      It might also be that a spider’s eight legs provide more stable locomotion while walking on a web, which constrains where a leg may be placed. In other words, stable locomotion on a web requires more legs than walking on the ground, which is a plane.

      🙂 Sarah

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