How Long Do Hedgehogs Hibernate? Hibernation Checker

General information only. Hedgehogs hide illness well. For a pet, see an exotic-animal vet; for a wild hedgehog in trouble, call a local hedgehog rescue. We give no medication or dosing advice.

How long do hedgehogs hibernate?

In the UK, wild hedgehogs usually hibernate for about 3–5 months, from November–December to March–April. The British Hedgehog Preservation Society (BHPS) says hibernation usually starts in November, December or even January, once the temperature drops and stays low, and ends from about mid-March to early April. Hedgehog Street gives October/November through to March/April. A radio-tracking study funded by PTES at two English sites recorded a hibernation period of 151 days — about five months.

So how long do hedgehogs hibernate for in a typical British winter? Roughly from Bonfire Night to Easter, give or take a few weeks, depending on how cold the winter is and how fat the hedgehog is. Whether you search "how long do hedgehogs hibernate" or "how long do hedgehog hibernate", the answer varies from one hedgehog to the next: in mild winters some stay active into November and December (Hedgehog Street).

The hibernation season at a glance

• Length: about 3–5 months (BHPS dates; 151 days in the PTES-funded study).
• UK start: usually November to January (BHPS).
• UK end: mid-March to early April (BHPS).
• New Zealand: mid-April to mid-September in colder southern regions (NZ Department of Conservation).
• Pet African pygmy hedgehogs: should never hibernate — a "hibernation attempt" is an emergency.

When do hedgehogs hibernate and wake up?

The hedgehog hibernation season follows the weather rather than the calendar. Hibernation starts when the temperature around the hedgehog becomes, and stays, low (BHPS). This month-by-month guide uses the BHPS, Hedgehog Street and PTES timings for the UK — the hedgehog hibernation months UK owners and gardeners usually ask about.

When do hedgehogs come out of hibernation? Most emerge between mid-March and early April. They wake hungry and lighter than in autumn, so a dish of water and some meaty cat or dog food or hedgehog biscuits is the best welcome (BHPS). In the southern hemisphere the seasons flip: in New Zealand, where hedgehogs are an introduced pest, those in colder southern regions hibernate from mid-April to mid-September, while North Island hedgehogs can be trapped all year round (Department of Conservation).

What happens to a hedgehog's body during hibernation?

Hibernation isn't sleep. The BHPS describes it as an energy-saving state in which the metabolism almost stops:

• Heart rate: falls from about 190 beats a minute to about 20 (BHPS).
• Body temperature: normally about 35 °C, drops to 10 °C or less (BHPS).
• Breathing: slows to about one breath every few minutes (BHPS).
• Fuel: the fat built up over summer and autumn (Hedgehog Street). In the PTES-funded study, females lost 14–25% of their body mass over the winter.

Temperature matters a lot. The BHPS says the best hibernation temperature is about 4 °C, and that at 10 °C a hedgehog burns its fat twice as fast. That's why a nest in a heated shed or a mild spell can be dangerous: the hedgehog uses up its reserves too quickly. So what temperature do hedgehogs hibernate at? Their bodies cool to near the temperature of the nest, ideally a steady few degrees above freezing.

Do hedgehogs wake up during hibernation?

Yes, regularly. The BHPS says hedgehogs wake up frequently during hibernation but rarely leave their nests; each waking spell lasts a day or two and can be triggered by disturbance or unexpectedly warm weather. Some do move house: Hedgehog Street notes that individuals move nest at least once over the winter, and the PTES-funded study found hedgehogs used about five different nests each, with some staying in one nest for at least 89 days.

Waking up costs a lot of energy. Hedgehog Street warns that any disturbance during hibernation can be extremely dangerous, because the hedgehog spends precious fat reserves becoming active. So can you wake a hibernating hedgehog to check on it? Please don't. If you uncover one by accident, cover the nest back up gently and leave it alone. A hedgehog seen out in daylight in winter, though, is a different matter — it needs help (see below).

How heavy should a hedgehog be to hibernate?

This is the question behind most autumn worries about a small hedgehog in autumn. In 2024, six organisations — the BHPS, the British Veterinary Zoological Society, the British Wildlife Rehabilitation Council, the RSPCA, Secret World Wildlife Rescue and Vale Wildlife Hospital — agreed a joint position on hedgehog hibernation weight for wild hedgehogs:

• No specific weight guarantees survival.
• Otherwise healthy young hedgehogs over 450 g (about 1 lb) can survive hibernation.
• Greater weight may help, but there's no evidence that it does.
• Hedgehogs under 450 g should normally be rescued from late October to February, depending on the weather and how often they visit feeding stations.
• Rescuing hedgehogs over 450 g on weight alone is unnecessary and "strongly discouraged": captivity is stressful and can spread disease.
• Any hedgehog out during the day, or ill or injured, should be taken into care whatever it weighs.

You may still see an older figure of 600 g. The BHPS once said young hedgehogs are more likely to survive at 600 g, and some guides still use it; the 2024 view is that there's no evidence extra weight helps a healthy wild hedgehog. The 600 g figure now applies to rehabilitated hedgehogs released in winter.

Underweight hedgehog: winter checklist

• Under 250 g in autumn: probably an orphan — contact a rescue now (BHPS).
• Under 450 g from late October to February: contact a rescue (2024 guidance).
• Curled up and cold out in the open, away from a proper nest: it isn't hibernating safely — it needs help (BHPS).
• Over 450 g, active at night and eating: leave it in the wild and keep food and water out.

Using the checker above in the UK: a 300 g hedgehog in January gets "Contact a hedgehog rescue", the same hedgehog in July gets "not hibernation season — weight alone isn't a worry", and a 600 g hedgehog is above the guidance in any month. Why does weight matter so much? About half of all first-year deaths happen in the first winter (Wildlife Online) — see our wild hedgehog survival explorer for the full picture.

Where do hedgehogs hibernate? Nests and hedgehog houses

A hedgehog's winter nest is called a hibernaculum. Towards the end of autumn hedgehogs choose sheltered spots: under hedges and the roots of trees, in piles of brushwood, inside compost heaps, in old rabbit burrows and under sheds and timber buildings (BHPS). The nest looks scruffy but is well built from dry leaves, grass and other plants, forming a dome 30–60 cm across with walls up to 10 cm thick (BHPS). That insulation keeps the hedgehog at a steady, cool temperature.

So where do hedgehogs hibernate in a garden? Anywhere dry, quiet and undisturbed. You can help by:

• leaving a corner of the garden untidy, with a leaf pile, log pile or brushwood heap;
• not forking compost heaps or clearing under hedges between November and April;
• checking bonfire piles before lighting them;
• putting out a hedgehog hibernation box (hedgehog house) in a quiet, sheltered spot.

A hedgehog house is simply one more dry nest site. Because hedgehogs move between several nests over the winter (PTES), having more than one option nearby helps. Once a box is in use, leave it shut until spring.

Do pet hedgehogs hibernate? Why pet hedgehog hibernation is dangerous

No — and they shouldn't. Pet hedgehogs are African pygmy (four-toed) hedgehogs from tropical Africa, not European hedgehogs. When they get too cold they can slide into hedgehog torpor, often called a "hedgehog hibernation attempt". Merck says torpor happens at temperatures below 20 °C (68 °F), and occasionally when it's very hot, and that it "suppresses their immune systems and can lead to impaired organ system function or starvation".

That's why African pygmy hedgehog hibernation is an emergency, not a normal behaviour. Unlike European hedgehogs, African pygmy hedgehogs haven't evolved to survive true hibernation. Signs described by hedgehog keepers (Furry Critter Network) include:

• a belly that feels cool rather than warm;
• lethargy, slowness and being hard to rouse;
• very slow breathing;
• staying curled in a tight ball and not uncurling when touched.

What to do: warm your hedgehog gradually, for example wrapped in a towel against your body, rather than with direct high heat, and call an exotic-animal vet straight away, even if it seems to recover. The checker's pet mode shows this message when you tick any of the warning signs. We give no medication or treatment advice — that's for your vet. Wobbling can be a sign of being chilled, but it's also the first sign of Wobbly Hedgehog Syndrome (Merck), so it always deserves a vet check.

How to keep a pet hedgehog warm

Vet sources agree on a warm, steady room, though their exact figures differ slightly:

• Merck: optimal 24–29 °C (75–85 °F); acceptable 22–32 °C (72–90 °F); torpor below 20 °C (68 °F).
• VCA: 21–29 °C (70–85 °F); below 15.5 °C (60 °F) hedgehogs become less active; they're also susceptible to heatstroke.
• Royal Veterinary College: 24–30 °C, out of direct sunlight to avoid extremes.
• University of Florida: 70–80 °F (about 21–27 °C), with a warm spot the hedgehog can leave if it gets too hot.

In practice: put a thermometer at hedgehog level, keep the enclosure out of direct sunlight (RVC) and away from cold draughts, and plan for cold nights, when most homes are coolest. Any heat source should warm part of the enclosure, not all of it, so your hedgehog can move away if it's too warm (UF). Ask your exotic vet which heating suits your setup. For how temperature fits into overall care and lifespan, see our pet hedgehog lifespan calculator.

How this hibernation checker works

Wild mode looks up the month in the UK or New Zealand season table, then compares the weight with the 2024 guidance. It gives one of these messages: out in the day, ill or injured → contact a rescue now; under 250 g from September to February → probably an orphan, contact a rescue now (BHPS); under 450 g from November to February → contact a rescue; under 450 g in October → watch closely and rescue from late October or if bad weather is coming; under 450 g in March or April → offer food and water after hibernation; under 450 g from May to September → weight alone isn't a worry; 450 g or more → above the guidance. Weights in ounces are converted at 28.35 g per ounce. For New Zealand the checker shows the season and notes that the UK guidance is for reference only, because hedgehogs there are an introduced pest.

Pet mode converts °F to °C and places the temperature in Merck's bands. If you tick a cold belly, lethargy or a curled, unresponsive hedgehog, it shows an urgent "warm gradually and call an exotic vet" message; wobbling on its own brings a "see a vet soon" note. Its limits: the checker can't examine a hedgehog. It gives general guidance from published veterinary sources, not a diagnosis, and a rescue or exotic vet always has the final say.

Frequently asked questions

This calculator gives an estimate for education and fun. Every pet ages differently — for health decisions, talk to your veterinarian.