• Question: What would be the main pros and cons of being able to hibernate?

    Asked by anon-189157 to Michael on 8 Nov 2018. This question was also asked by anon-189197.
    • Photo: Mike Ambler

      Mike Ambler answered on 8 Nov 2018:


      Hi, great question, thanks!

      Well for animals that hibernate, the advantage is that they are able to live in an environment in which there isn’t always enough food available. So some bears hibernate during the winter because they live in the north, and in winter there is hardly anything available to eat. Staying ‘awake’ during the winter would mean they needed to spend a lot of energy keeping themselves warm and moving around looking for food. Because there isn’t much around in the winter, this would be a waste of time and energy and they might not survive. Instead they simply switch themselves off for a the winter: they hardly move and they cool down. When they cool down, they are saving energy in two ways: firstly, they are not using energy to heat themselves up, and secondly, when we are cool all the processes in the body that use up energy slow down and so this also reduces how much energy they are spending staying alive. Then, when the winter is over they wake up, warm themselves up and start to find food again.

      Smaller animals like mice will also switch themselves off, but they do it for shorter periods of time. This is because generally these mice don’t live in places where the winter is very cold and long but they might find that some days it is a bit colder than usual and there isn’t much food around. In this case, the mouse will switch itself off – cool down and stop moving, and then wait a while before waking up in the hope that there is now more food or the weather is better! Small animals like mice have to spend a lot of energy keeping themselves warm and so sometimes it just isn’t worth the effort.

      The main disadvantages for bears are (I guess) that if the winter is long or they don’t have enough fat reserves to keep the basic functions working during hibernation then they might run out of energy before winter is over and they could die. For mice, they are at risk of being eaten while they are in torpor, and because they have stopped moving around, there is a chance that when they wake up there will still be no food around and so it might have been better for the mouse to have spent the time moving somewhere else where there might be food.

      When animals are hibernating they hardly need to breath and their heart pumps much less because they don’t need much blood flow. This is what makes it interesting to me as a doctor, because I would like to be able to make humans able to survive hardly breathing and having little blood flow for short times like when they are very sick or when they are having complicated operations.

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