Hedgehogs are small mammals covered with spines; they inhabit Europe, Asia, Africa and are common visitors in British gardens. Hedgehogs have changed little over the past 15 million years. Like many early mammals they have adopted a nocturnal life based on feeding on insects.
Physically distinguished by their spines, which are hollow hairs filled with keratin for rigidity. The spines are not poisonous but are as sharp. When threatened hedgehogs are able to wrap around themselves into a ball of spikes. The effectiveness of this ability depends on the number of spikes they have.
All species of hedgehog are mainly nocturnal, although some may be more active during the day than others. They sleep during much of the day in the grass or in holes in the ground. Normally hedgehogs burrow for protection. All species undergo periods of dormancy, they hibernate in winter.
They have 5 toes with long nails on the hind limbs, while in the front have 5 fingers with short nails used for digging up insects. Hedgehogs emit a broad range of sounds with which to communicate, from growls to high shrieks.
Although they can be a pain to gardeners because of their digging, they are still an essential part of any garden ecology and should be encouraged, a bowl of milk is a favourite treat that will attract them.