Hedgehogs search for food after dark, and locate their food by smell and hearing rather than sight. The hedgehog can eat up to one third of its weight every day. Its diet consists of worms and insects, small rodents, frogs, slugs, the eggs and young of ground nesting birds, and vegetable matter which includes roots and fruit. Hedgehogs can sometimes be seen after rain foraging for earthworms. Their resting time is mostly in daylight, when they curl up under cover of bush or grass or in a hole in the ground. They change shelter daily, except when the colder months come, as they hibernate during that time, only emerging to eat during warm spells. Hedgehogs are fairly vocal, and communicate in a series of grunts and snuffles. When alarmed, they emit a high-pitched cry. Although they generally move slowly, they are capable of moving quickly by rising high on their long legs. Usually litter size is two to four (although it has been known to reach 11), and the young are born during the summer months.