Insectivores evolved during the late Cretaceous period about 100 million years ago. Insectivores were the first placental mammals to nourish their offspring inside the body of the female. Human beings are direct descendents of these primitive beady-eyed bug-eating animals. Other famous insectivores include both shrews and moles, and the hedgehog's kissing cousin the spiny tenrec of Madagascar.

Hedgehogs are members of the family Eurincidae, which also includes the garlic- scented Moon Rat of Southeast Asia. At one- and-a-half feet long, Moon Rats are the largest living insectivores.

Hedgehogs are nocturnal, coming out at night to feed on insects, worms, snails, birds' eggs, and small vertebrates like frogs and snakes. They are often found in garbage dumps, or in close-proximity to human homes. Hedgehogs are solitary animals, who rarely come together except to mate (although they occasionally gather in places where there is an abundant source of food).

There are 14 species of hedgehog, of which there are four major classifications: Eurasian and European Hedgehogs, African Hedgehogs, Desert Hedgehogs, and Long-eared Desert Hedgehogs. It is thought that the long-eared varieties use their ears to help dissipate heat. Hedgehogs are found throughout the Old World, including parts of the Ukraine, India, China, the Gobi desert, Morrocco, Iran and Pakistan, South Africa, Western Europe and the British Isles. In England, they are protected by law. Hedgehogs living in northern climates hibernate during the winter, but in warmer places they are active year- round.

In the English-speaking world, hedgehogs were originally known as "urchins". According to the BBC
"This explains the meaning of 'sea-urchin', as these marine creatures have an appearance resembling the hedgehog. The phrase 'street urchin' also comes from hedgehogs, as both have a rather pugnacious look when they fix their beady eyes on you." ("Hedgehogs", BBC-h2g2, 1/25/01)

Most hedgehogs kept as pets are actually African White-bellied Hedgehogs. They are frequently sold as "Dwarf Hedgehogs" or "African Pygmi Hedgehogs." Because of their compact faces and white underbellies, these hedgehogs are particularly appealing to human beings. The European hedgehog has a slightly longer snout, and a mottled brown coloring which gives it an appearance somewhat similar to that of a miniature wild boar -hence the name.