The Hedgehog, Erinaceus europeaus, is a mammal of the order Insectivora, about 20cm in length. Its back is covered in spines, and when threatened it rolls itself up in a ball. It thus has no natural predators, but its defense strategy is ill-adapted to road vehicles.
It is common in Europe, and often can be found in gardens -- where they are considered a useful form of biological pest control. Its diet consists of snails, worms, and insects, but many people put food out for hedgehogs.
Its gestation period is 58 days; and they live 4-7 years, though longer is known: up to 16.
An anti-submarine weapon developed during World War II, the hedgehog was deployed on most destroyers to supplement the depth charge. Many small bombs were launched from spiked fittings, hence the name. The bombs exploded on contact and achieved a higher sinking rate against submarines than depth charges did.