• Question: Hi. Is it true that our blood is blue? If so, why do we see it red?

    Asked by eden4 to Alexis, Dr D, Helen, Jasmine, Mario on 18 Jun 2013. This question was also asked by amaan.
    • Photo: Alexis Barr

      Alexis Barr answered on 18 Jun 2013:

      No – this is not true. Blood is red because red blood cells contain lots of a molecule called haemoglobin. Haemoglobin is red and is very important for carrying oxygen around our bodies.
      Blue blood does exist though – but in animals like spiders and molluscs. That’s because their blood doesn’t contain haemoglobin.

    • Photo: Jasmine Penny

      Jasmine Penny answered on 18 Jun 2013:

      Some animals do have blue blood but not us! Our blood is red because of a molecule called haemoglobin!

    • Photo: Mario Ruiz

      Mario Ruiz answered on 20 Jun 2013:

      Nah, our blood is red, not blue! But why if you look at the back of your arm some veins apear to be blue or even green? Well, that’s because the blood circulating through the veins is lacking oxygen, which makes it have a purple-ish colour, in comparison to the arterial blood, that is very red (full of oxygen). When you cut yourself and blood comes out, no matter from a vein or an artery, it is always red because it reacts with the oxygen of the air.

    • Photo: Andrew Devitt

      Andrew Devitt answered on 21 Jun 2013:

      @eden4
      @amaan
      Nope! It’s red but different shades of red and all because of haemoglobin. BUt there are other organisms that use different things to haemoglobin and their blood can be very different colours (including blue I believe)

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