Why do hedgehogs hibernate?
Hibernation is more about conserving energy than sleeping. Hedgehogs hibernate to avoid the cold months of the year when food becomes scarce. During winter months they often use up more energy searching for food than the energy they get from the food itself.
It is important that they have enough fat reserves to survive hibernation. Generally a hedgehog may lose one third of its body weight during hibernation and therefore a minimum weight of 600g is needed to survive the winter. If a hedgehog has not reached a good weight before it hibernates, it will still go into hibernation but without the required fat reserves it is likely to die as it sleeps.
“A hedgehog needs to weigh at least 600 grams in order for it to survive hibernation”
When do hedgehogs hibernate?
They usually hibernate between November and mid March but if the weather is mild many hedgehogs are not hibernating until January when the frosts and cold weather is at its worst.
During hibernation some hedgehogs will often wake if the weather is milder to search for food and they will use up their fat reserves.
What happens to the hedgehog during hibernation?
Prior to hibernating the hedgehog will be very busy building a nest. While hibernating, the hedgehog’s body tries its best to conserve as much of the stored body fat as it can.
- It stops being warm blooded, since this uses up too much energy.
- The hedgehog becomes cold to the touch.
- The hedgehog stops moving.
- It can stop breathing for long periods of time
- The heart rate drops to around 20 beats per minute.
To wake up, the hedgehog needs to use its fat reserves, which warms the body and begins to get the blood flowing again. Only then does the hedgehog have a normal body temperature and can again venture out into the world.
Only at the start of spring will the hedgehog start to become fully active again.
“Hibernating hedgehogs can appear dead so if in doubt seek advice”
Do hedgehogs have to hibernate?
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.
Hedgehogs taken into care due to injuries or being under weight, do extremely well and are all the more fit and healthy for not hibernating.
How you can help?
You can provide a suitable hedgehog home (see where I like to sleep) Place the box in a suitable quiet, sheltered position, under a bush or small tree or against a sheltered wall, fence or shed so that the hedgehog feels protected. Make sure the house is waterproof by covering it with tarpaulin, plastic sheet or roofing felt.
Make sure there is a plate of meat based cat biscuits and a shallow dish of water available throughout the winter. Don’t put wet food down for the hedgehog as it could freeze
If you accidentally disturb a hibernating hedgehog nest, simply cover it back up and leave it there.
If you find a hedgehog weighing less than 600gms between late September and early March, then it needs help. Contact your local hedgehog rescue or the British Society for the Preservation of Hedgehogs for further advice.