Hedgehog

Lore & Background

Hedgehogs are easily recognized by their spines, which are hollow hairs made stiff with keratin. They roll into a tight spiny ball when threatened, tucking in the furry face, feet, and belly. Hedgehogs are primarily nocturnal and sleep for a large portion of the day under bushes, grasses, rocks, or in dens dug underground. All wild hedgehogs can hibernate, though the duration depends on temperature, species, and abundance of food. Hedgehogs are fairly vocal, with a variety of grunts, snuffles and/or squeals. They occasionally perform a ritual called anointing: when encountering a new scent, they lick and bite the source, form a scented froth in their mouth, and paste it on their spines. Some experts believe this might serve to camouflage the hedgehog with the local scent and might also lead to infection of predators poked by the spines. Hedgehogs have some natural immunity against some snake venom through the protein erinacin in their muscles, though in such small amounts that a viper bite may still be fatal. They are one of four known mammalian groups with natural protection against α-neurotoxin. Hedgehogs are omnivorous, feeding on insects, snails, frogs, snakes, bird eggs, carrion, mushrooms, grass roots, berries, and melons.

Reader's Guide

Hedgehogs hold significance as a widely recognized mammal with a unique defensive adaptation of spines. They are commonly brought to wildlife clinics in Europe, where they are known to be sensitive and easily stressed by humans, sometimes fatally. Hedgehogs have been introduced as invasive species in areas such as New Zealand and the islands of Scotland, where they lack natural predators and have decimated native species including insects, snails, lizards, and ground-nesting birds. Eradication efforts have been controversial, with legal injunctions prohibiting killing in some areas. Hedgehogs are also kept as pets, with the most common pet species being hybrids of the white-bellied hedgehog and the North African hedgehog, though ownership is restricted in some US states and Canadian municipalities. They suffer from various diseases including cancer, fatty liver disease, and a rare condition called balloon syndrome, where gas is trapped under the skin.

Did You Know?

• Hedgehogs have changed little over the last 15 million years.
• Hedgehogs are one of four known mammalian groups with natural protection against snake venom α-neurotoxin.
• Hedgehogs can suffer from balloon syndrome, a rare condition where gas is trapped under the skin, unique to hedgehogs because their skin is baggy enough to curl up.