The hedgehog family, Erinaceidae, includes 19 individual species of small insectivorous mammals. The animal most people think of when they hear this name is actually Erinaceus europaeus, the European hedgehog, which is readily identifiable by the distinctive spines along its back. Spined hedgehogs can be found in Europe, Africa, and Western Asia. Nonspined relatives, known as gymnuras, can be found in Eastern Asia.
The classic European species has a series of stiff spines mixed in with the coarse hair on its body. The spines can be found along the back and sides, and they are not barbed like those of the porcupine. The underside of the animal is soft and tender, and when threatened, it will form a protective ball with its spines facing out. Hedgehogs have short tails and expressive faces, which have made them popular characters in children's fiction.
When mature, spined species can range in length from 4 to 17 inches (10 to 44 centimeters) long. Smaller species, such as the African Pygmy, are sometimes kept as pets in places such as Europe and North America. The gentle yet expressive animals are popular pets because they are relatively clean, sweet smelling, and easy to train. Pets tend to be playful and loving, assuming that they were born in captivity, and many hobby associations around the world promote their ownership and offer education as well.
The gymnuras resemble large rats, with long tails and stiff body hair, but no spines. They tend to be much larger at maturity, with the largest specimen being the Moon Rat, which can grow up to 18 inches (46 centimeters) long. Gymnuras do not make good pets, largely because they have a rather offensive odor.
Hedgehogs eat a diet composed mainly of insects and small reptiles, although they will also eat plant material to balance their nutrition. In captivity, they can be fed specially formulated food, while some pets are maintained for pest control purposes in the garden. Because these animals are not destructive to gardens, they are an excellent natural pest control option.
The hedgehog is sometimes confused with the porcupine, a new world rodent that is actually in an entirely different family. Porcupines tend to be much larger, and they are also equipped with painful barbed quills. Because of this, porcupines are usually not kept as pets, although some zoological parks have families on exhibit.