• Question: If animals like whales and dolphins, have to come up for air every so often, what causes them to live in the water aside food resources?

    Asked by winchester to Andrew, Emma, Marianne on 22 Jun 2010 in Categories: .
    • Photo: anon

      anon answered on 22 Jun 2010:

      I suppose that’s a strange way to pose the question. They have access to air and water. They coudn’t live in the air because they can’t fly. They couldn’t live on land because they couldn’t get around.

      They can access everything they need from the water and they are sufficiently different from the other creatures there to be successful.

      I guess you could say evolution and specifically adaptation…

    • Photo: Marianne Baker

      Marianne Baker answered on 22 Jun 2010:

      They’re mammals!
      Fish breathe oxygen from water using gills, and some amphibians absorb oxygen through their skin.
      Mammals, however, use lungs and need air to get oxygen.

      Whale evolution is very interesting actually. Here you go! http://en.wikipedia.org/wiki/Evolution_of_cetaceans#The_earliest_cetaceans:_Pakicetids_or_Indohyus.3F

      For a long time the relationships between whale species was incorrectly categorised. Once we had DNA sequences, some surprises came along.

      So, it seems that a niche (niche meaning part of the environment that is available for species with certain characteristics to thrive in) existed in the sea for mammals! It was filled; land mammals became more and more adapted to living in the water over time, until they began to exist in it completely.

      Brilliant!

    • Photo: Andrew Maynard

      Andrew Maynard answered on 22 Jun 2010:

      Hi winchester,

      I’m not a biologist, but I suspect that, even though they need to come up from air, they are still supremely well-adapted to their environment.

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