Hedgehogs hibernate to bypass the cold months of the year when food becomes scarce. If the weather is warm and food is put out for them every night, some hedgehogs do not feel the need to hibernate and will stay active all through the winter.
Hibernation, however, is more than just sleeping for a long time. The hedgehog, to some extent, puts itself into a type of suspended animation. Hibernation begins for most hedgehogs in October or November. They can be seen wandering about, however right up until Christmas or even after, especially if the hog has not managed to collect enough food to see itself through the winter. They can also be upset by a warmer spell of weather and will wake up and perhaps go for a forage for food.
With the climate changes and our warmer winters, many hedgehogs are not going into hibernation until well into January when the frosts & cold weather is at its worst.
- Hedgehogs do not hibernate continuously.
- They get up for a few days at a time all throughout the winter.
- They are desperately looking for food to top themselves up before going back into hibernation as the weather gets colder again.
- Put down cat or kitten biscuits, peanuts, cheese etc. See Feeding Hedgehogs page for more advice.
- Tinned food will freeze, so is no good for them.
- Put food and water down all the time. This food will be a life saver.
When you are having YOUR Christmas Dinner, please remember the hedgehog in YOUR garden who needs his as well
A hedgehog needs to weigh at least 600 grams in order for it to survive hibernation
If you find a hedgehog weighing less than this in the period between late September and early March, then it needs help. Bring it in and contact for advice and help.
Whilst the hedgehog is in hibernation, a number of odd things happen to it.
- The hedgehog stops being a warm blooded animal since this uses up too much energy. Its body temperature falls to match that of the surrounding environment. However, the surrounding temperature must not be below freezing (the ideal temperature in the nest for successful hibernation is about 5º c) and if it rises too much, the animal’s blood flow will increase and start to use up too much stored fats.
- The hedgehog becomes cold to the touch.
- The hedgehog stops moving.
- The breathing stops for long periods of time
- The heart rate drops to around 20 beats per minute.
- Internally, the chemistry of the blood and the major organs all alter to avoid using too much of the stored fats.
So in the hibernation state, the hedgehog’s body tries its best to conserve as much of the stored body fats as it can.
To wake up, the hedgehog needs to metabolise fat which warms the body and begins to get the blood flowing again. The hedgehog may help itself along by shivering. This can all take from 1/2 to 1 hour to complete. Only then does the hedgehog have a normal body temperature and can again venture out into the world.
Obviously, successful hibernation depends a lot on the surroundings being of an acceptable temperature to allow the body to evenly use up the body fats. To achieve this, the hedgehog will have built a nest somewhere in the weeks leading up to it’s hibernation. Hedgehogs do wake up every now and again though, usually due to a warm spell of weather or if, perhaps the nest has become water logged.
Only at the start of spring will the hedgehog start to become fully active again.
IS HIBERNATION NECESSARY?
No, hedgehogs don’t have to hibernate, Indeed the hedgehogs taken into care due to injuries or being under weight, do extremely well and are all the more fit and healthy for missing it. As mentioned before, hibernation is one of the most dangerous times for a hedgehog in the urban environment. In warm weather they have no problem finding sufficient food but as the weather gets colder the insects on which they feed, become scarcer and more difficult to find. The hedgehog can use up more energy looking for food than it gets from eating what it does find.
We can help the hedgehog by providing a suitable place to hibernate or survive the winter in your garden.
Provide a box similar to this one, that the hedgehog can either hibernate in, or if you continue to provide plenty of food and water for him, he might stay awake over the winter period.
Place the box in a suitable quiet, sheltered position, under a bush or small tree or against a sheltered wall, fence, shed etc. So that the Hedgehog feels protected and cover the box with a waterproof material, such as tarpaulin or plastic sheet or roofing felt.
Make sure you continue to put down food and water all through the winter because they do wake up frequently and need it
If you are a handy person you could make your own box as shown on the houses page or buy a ready made one from the links on that page