How can you tell if a hedgehog is hibernating? This is a question I am frequently asked by my foster carers, a network of special people who support me with looking after rehabilitated hedgehogs over the Winter period. These hedgehogs missed the deadline for release before the weather turned cold and, if they are well enough and heavy enough (absolute minimum of 650g), they will be allowed to hibernate in captivity.
Hibernation is not like sleeping. The hedgehog won’t be roused by touch or by noise. Hibernation is a state of torpor, where the core body temperature has dropped, the heart rate and breathing have slowed right down and normal activity has stopped. A hibernating hedgehog will be completely rolled up into a tight ball with no face visible.
Lucky, a hibernating hedgehog, just before his weight check
You can tell that the hedgehog is hibernating and not dead by the fact that it will ‘ripple’ when touched very gently. It may also emit a little ‘snore’!
Video of a hibernating hedgehog
Please don’t read this post and think you should go around disturbing the hibernating wild hedgehogs in your garden to check on them. I only check on these hedgehogs during hibernation because they have been poorly. Weight checks every few weeks will alert me to any potential problems and they can be woken up again if they have lost too much weight. I use a special calculator from a wildlife rescue to assess whether their weight loss in hibernation is acceptable or not. Waking up a hibernating hedgehog is also a specialist task, so please do not try this yourself.
The best advice is not to disturb a hedgehog in hibernation. Take care when gardening in Winter. Don’t be tempted to tidy up piles of leaves or logs – they may be home to a hibernating hedgehog. If you do disturb one, cover it back up straight away – unless there is a chance that you have caused injury e.g. with a fork. In that case, you must take it straight to a hedgehog rescue.
Hibernation is also not a continuous state. Hedgehogs will wake up during periods of milder weather for a quick snack or sometimes even to move their hibernaculum if the warmer spell lasts for a few days. I always leave out a bowl of water in the garden and a little food year round to help hedgehogs that have briefly woken from hibernation.
With a little luck, hedgehogs that were healthy when they hibernated will wake in the Spring. The exact timing depends upon the temperature and can be as early as March or as late as May. They will emerge hungry so Spring is a great time to put out hedgehog feeders and make sure that you can give them a hearty breakfast when they emerge….
I run a hedgehog rescue in York, England, you can support my work at www.littlesilverhedgehog.etsy.com