Hibernation

Hibernation is much more than just a lengthy sleep, it is a complex process of energy conservation in which the animal’s metabolic rate, cardiovascular system and respiratory rate all slow right down to the minimum level required to preserve life.  A hedgehog deep in hibernation can easily be mistaken for dead as it will be very cold and still and may not breathe for long periods of time.  It will be curled up very tight, so tight in fact it may be hard to find the head, the hedgehog will bristle when touched, where as a dead hedgehog will be uncurled and unresponsive to touch.

During hibernation the hedgehog will live off the reserves of fat it has spent the early autumn building up, hedgehogs must reach the critical weight of at least 600g before entering hibernation in order to stand any chance of surviving the winter.  In early autumn hedgehogs will devote a lot of time to building their winter nest (hibernaculum).  The hiberniculum is made of dry leaves and grass, it takes several nights to make, it has to be water- and weatherproof, so that the inside temperature remains constant, whatever the weather does outside. The hedgehog carries leaves and grass in its mouth until it has made a big pile, then it goes round and round inside, weaving a sturdy nest with its spines. The nest is built under brambles or some other sort of support to keep it in shape.  Hedgehogs will make several of these nests