Question: What are the factors that affect necessity, time and other about hibernation in animals?

Mike Ambler answered on 7 Nov 2018:

Hi, interesting question, thanks!

Well usually animals hibernate when they find themselves in a situation where the energy needed to keep themselves active, warm and looking for food is more than the amount of energy they can find in food…

What this means is that some animals will hibernate for a long period (like the whole winter) because during this time there is hardly any food around – plants aren’t making fruit, their prey has migrated etc. This is what bears do. Smaller animals, because they have a lot more skin surface compared to their body mass, lose heat quickly and so must eat a lot everyday in order to have enough fuel to keep themselves warm. And because they are small, there is less stored fuel in the form of fat. Because of these two factors (needing to spend a lot of energy keeping warm, and having little room for storing fat), smaller animals like mice will often do short hibernations (called daily torpor) if they find that there is not enough food around or if it is cold. These periods last only a few hours, and give the animal a chance to switch off wasting energy staying warm when there is nothing to eat.