Mammals
European Hedgehog
Erinaceus europaeus · also called common hedgehog, West European hedgehog
The European hedgehog is one of the best-loved wild animals in Britain and continental Europe — a small, snuffling, spine-covered insect-eater that patrols gardens at night, rolls into a prickly ball when alarmed, and sleeps away the winter. It is also, increasingly, a species in trouble.
Overview
European hedgehogs live across western and central Europe, in woodland edges, hedgerows, rough grassland, farmland margins, parks, and gardens — anywhere with cover for nesting and a supply of ground invertebrates. They are nocturnal, solitary, and mobile, covering one to two kilometres a night in search of food, and they need a connected landscape of gardens and green space to do it. They shelter by day in nests of leaves under hedges, log piles, and sheds.
Spines and the ball
A hedgehog carries around 5,000 spines — stiff, hollow, modified hairs — over its back and sides, with soft fur on the face, legs, and belly. A muscular drawstring around the edge of the spiny skin lets it pull that skin down over its whole body and curl into a ball, presenting nothing but points. This works against almost every predator; the main exception is the badger, strong and long-clawed enough to unroll one.
Hibernation
In autumn hedgehogs eat heavily to lay down fat, then build a tight winter nest and enter true hibernation for three to five months, their body barely ticking over. They rouse periodically to shift nests. A hedgehog that goes into winter underweight — often because it was born too late in the year — frequently does not wake up, which is why autumn “hedgehog rescue” and supplementary feeding are widespread.
Odd behaviour
Hedgehogs self-anoint: on meeting a strong new smell they chew the source, work up a lather of frothy saliva, and spread it over their spines. The purpose is genuinely unknown — theories range from camouflage to arming the spines with toxins.
Status and helping hedgehogs
The European hedgehog is now Near Threatened, and in Britain its numbers have fallen dramatically since 2000, especially in the countryside. The drivers are habitat loss and fragmentation, intensive farming and pesticides, road deaths, garden fences that block foraging routes, and hazards such as slug pellets, strimmers, and steep-sided ponds. Simple measures help a lot: leaving a “hedgehog highway” gap in fences, keeping a wild corner, avoiding pesticides and slug pellets, and checking long grass before mowing.
European Hedgehog: common questions
How do hedgehogs curl into a ball?
A hedgehog has a sheet of muscle, the orbicularis, running around the edge of the spiny part of its back like a drawstring. When it contracts, the loose, spine-covered skin is pulled down over the head, legs, and belly, and the animal tucks its vulnerable underside inside. The spines then point outward in every direction. A tightly curled hedgehog is almost impossible for a fox, badger, or dog to open, though badgers — with their long claws and strength — are one of the few predators that can.
Do hedgehogs really hibernate?
Yes, true hibernation — not just sleeping through cold spells. As autumn temperatures fall and food runs short, a well-fed hedgehog builds a compact nest of leaves and grass and enters a state in which its heart rate drops from around 190 beats a minute to about 20, its breathing nearly stops, and its body temperature falls to within a few degrees of the surroundings. It wakes and re-nests several times over the winter, burning through fat reserves, and emerges in spring. Underweight hedgehogs (usually under about 450 g) often do not survive the winter.
What is "self-anointing"?
When a hedgehog encounters a strong or novel smell — a particular plant, a piece of leather, tobacco, a toad's skin — it may lick and chew the source, produce large amounts of frothy saliva, and then contort itself to spread the foam over its own spines with its tongue. No one is sure why. Suggested explanations include camouflaging its own scent, applying toxins from toads or plants to the spines as a chemical deterrent, or a form of scent-marking. It looks alarming but is normal behaviour.
Why are hedgehogs declining?
The European hedgehog was reclassified as Near Threatened as evidence of widespread decline accumulated. In Britain the population has roughly halved in rural areas since 2000. The causes are the loss and fragmentation of hedgerows and rough grassland, intensive farming and pesticide use that removes their invertebrate food, road mortality, the tidying and fencing of gardens (which cuts off the connected foraging routes hedgehogs need), badger predation where hedgehog numbers are already low, and hazards like slug pellets, strimmers, drain covers, and garden ponds with steep sides.