• Question: Why does your fingers turn wrinkly in water?

    Asked by brooket__ to Franco, Koi, Mark on 23 Jun 2016.
    • Photo: Franco Falcone

      Franco Falcone answered on 23 Jun 2016:

      Brooket
      there are a few different answers. This happens more rapidly if you are e.g. bathing in warm water, The warm water will remove the oily layer (called sebum) which your skin produces to make it water-proof. So when you remove the water-proof layer, water is able to enter between the cells of your skin, and make it swell and increase in volume – that’s the old explanation. The newer explanation (which does not necessarily contradict the old one) is that prolonged soakin in water causes a response in your nervous system which makes your skin go all foldy and wrinkly, because that give you a better grip in water (which might have been of some advantage in our ancsetors when moving in water, for example seeking food). But to be honest, I don’t really know !

    • Photo: Mark Booth

      Mark Booth answered on 23 Jun 2016:

      Hi Brooket

      The latest theory that I am aware of is that we evolved wrinkly fingers in water to help with gripping things that we need to manipulate in water. This theory has been tested – as many are – through serendipity. Patients with nerve damage to their fingers do not get wrinkles.

      You can test the theory yourself. Put some marbles in water then try and take them out with dry hands. Then keep your hands in some water until they grow wrinkly. Repeat the experiment and time how long it takes each time to retrieve, say, 10 marbles.

    • Photo: Arporn Wangwiwatsin

      Arporn Wangwiwatsin answered on 23 Jun 2016:

      Hi Brooket,

      I’m not an expert for this but so far I’m more convinced by the “better-gripping” explanation. Because…if it’s by the skin losing the oily layer, then why is it just the fingers and not skin in other parts of the body too that go wrinkly? .. I might have missed something here though 🙂

      I like Mark’s idea for testing the “better-gripping” explanation… maybe we can also test the loss-of-oily-layer explanation by putting hands in a liquid isotonic to our skin (that is it has the same osmotic pressure as our skin, hence the skin should not lose or gain water when in that solution)..and see if the skin still go wrinkly.

      Or maybe it is both … maybe the nerves on the skin respond by causing the loss of oily layer (in addition to the loss by being in warm water) to make the skin go wrinkly faster!

      That was a lot of “maybe” so take my speculations with lots of care! 😉

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