Twelve hedgehog facts, fact-checked
Hedgehogs are ancient insectivores and one of Britain's most-loved garden animals, in serious decline. Full profile in our hedgehog guide.
1. About 5,000 spines
Modified hairs of keratin, hollow and each on a flexible base. They are not barbed and are not shed defensively.
2. Curling up is muscular
A powerful ring of muscle draws the spiny skin into a ball, protecting the soft underside.
3. They self-anoint
On meeting a strong smell or taste, a hedgehog chews it into frothy saliva and flicks it across its spines. No explanation is settled — camouflage, deterrence and parasite control have all been proposed.
4. They tolerate some venoms
Partial resistance to certain snake venoms, from a blood protein — the same trick seen in mongooses and honey badgers.
5. They are lactose intolerant
Bread and milk, long left out for them, causes serious digestive harm. Meat-based pet food and water are appropriate.
6. They travel over a mile a night
Roaming widely to forage, which is why fenced gardens fragment their range so badly.
7. Hibernation is not sleep
Body temperature and heart rate drop dramatically. Waking is costly, so disturbance in winter can be fatal.
8. Hoglets are born with soft spines
Beneath fluid-filled skin, so the mother is not injured. Spines harden within hours.
9. They can swim and climb
Which is why steep-sided ponds are a hazard — a hedgehog that cannot find a sloped exit drowns.
10. British numbers have fallen sharply
Habitat fragmentation, road deaths, tidy gardens, slug pellets and loss of hedgerow and rough ground have driven a steep decline.
11. Hedgehog highways work
A 13 cm gap at the base of a garden fence reconnects fragmented territory — one of the most effective simple interventions available.
12. Check before you strim or light a bonfire
Long grass and unlit bonfire piles are classic nesting sites. Checking first prevents a large share of avoidable deaths.
Read the full hedgehog wildlife guide for IUCN status, population context and sources — or donate to WARN to help fund the partner teams protecting wildlife on the ground.
