Hedgehog

5,000 spines and a curling defense

A typical hedgehog has about 5,000-7,000 spines covering its back and sides — modified hairs made of keratin. The spines are not poisonous (unlike porcupine quills, hedgehog spines don’t detach) but provide formidable defense.

The signature defense: when threatened, hedgehogs curl into a tight spiky ball, presenting only spines outward. Special muscles run along the body that draw the spines around the curled hedgehog. The defensive ball is essentially impenetrable to most predators — only badgers and large birds of prey have learned to attack hedgehogs successfully.

A garden helper, declining fast

In the UK, hedgehogs have traditionally been welcome garden visitors — eating slugs, snails, beetles, and other garden pests. A single hedgehog can consume hundreds of slugs over a season, providing significant natural pest control.

But UK hedgehog populations have declined dramatically since 2000:

• Estimated UK population fell from 30+ million to under 1 million by 2020
• 97% loss in some agricultural areas since 1950
• Major causes: habitat fragmentation, road traffic, pesticides, garden tidiness (less brush for nesting)

The British Hedgehog Preservation Society has lobbied successfully for various habitat protections, and “hedgehog highways” (small holes between gardens) are now actively promoted to fragment-resistant populations.

Different from porcupines

Hedgehogs and porcupines are sometimes confused but belong to entirely different orders:

• Hedgehog — order Eulipotyphla (insectivores), small size, defensive ball
• Porcupine — order Rodentia (rodents), much larger, detachable barbed quills

The two species independently evolved spines as defense — a classic example of convergent evolution. Despite the similar appearance, they’re as unrelated as mice and dogs.

Hibernation specialists

European hedgehogs hibernate through winter — typically October to April depending on latitude. Hibernation requires:

• Sufficient pre-winter weight (typically 600+ grams)
• A safe nest site (leaf piles, brush piles, log piles)
• Stable cool temperatures (5-10°C optimal)
• Multiple awakenings during winter (don’t sleep continuously)

Underweight hedgehogs entering winter often don’t survive hibernation. Wildlife rescue organizations in the UK rescue and overwinter underweight hedgehogs in autumn, releasing them when warmer weather returns.

Pet hedgehogs

The African pygmy hedgehog (Atelerix albiventris) — a smaller, more docile species — has become popular as a pet, particularly in the US since the 1990s.

Pet hedgehog considerations:

• Nocturnal (active at night, sleep during day)
• Solitary (don’t keep multiple together)
• Specialized diet (commercial hedgehog food, insects, occasional vegetables)
• Salmonella risk (regular handwashing required)
• Legal restrictions in some places (banned in California, Hawaii, several other states)

European hedgehogs cannot be kept as pets in most countries — they’re protected wildlife in the UK and most of continental Europe.

A cultural icon

Hedgehogs appear extensively in European children’s literature and folklore:

• Beatrix Potter’s Mrs. Tiggy-Winkle — classic children’s hedgehog character
• The Brothers Grimm’s “Hans my Hedgehog” — German fairy tale
• Sonic the Hedgehog — Japanese-American video game character
• Hedgehogs in folk medicine — traditional remedies in various European cultures

The animal’s appealing appearance (small, round, spiky but not threatening) makes hedgehogs popular subjects for children’s books, illustrations, and merchandise across the world.