• Question: why do some animals have shorter/longer life spans than others?

    Asked by EM26 to Siana, Sara, Richard, Peter, Carolyn on 17 Nov 2015. This question was also asked by Megan <3, EquiCH.
    • Photo: Richard Unwin

      Richard Unwin answered on 17 Nov 2015:

      EM26,

      That’s a great question with several answers.

      It seems to be controlled by how much damage our DNA can take – a comparison of pigeons (live for 35 years) and rats (live for 7 years) showed that the pigeons make fewer DNA damaging chemical when their cells make energy – that protection probably helps them live longer. There is also a relationship with size – bigger animals tend to live longer. This may be because they need to have stronger hearts to pump blood and nutrients round the body and they need to use those nutrients more efficiently to keep at a steady large size.

      My pet theory is that smaller animals have to grow quickly and reach reproductive age (to pass on their genes) quickly i.e. before they get eaten, so they have fast metabolisms and grow quickly to reach that point, with the knock-on effect that they ‘age’ faster in doing so.

    • Photo: Sara Falcone

      Sara Falcone answered on 18 Nov 2015:

      Hello 🙂

      There is this theory, called rate-of-living theory, that says that the smaller an animal is the faster it metabolism is the shorter is the life span and since small animals have a fast metabolism they live less.
      I guess that some years ago somestudies demostrated that it is actually not like that. I personally don’t believe it works that way but hey, for the sake of science, I give you all my knoledge!

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