Gymnures and Hedgehogs: Erinaceidae

Most members of this family are nocturnal, active only at night. Some species, like the lesser gymnure, may venture out in the daytime if they become hungry enough, but they usually spend their days resting in a sheltered spot. In the winter, many cold-climate species have the ability to slow their body processes, and essentially enter a deep sleep known as hibernation until the weather warms. The European hedgehog sometimes hibernates for six or seven months, surviving on body fat it stored when it was active earlier in the year. Warm-climate species do not have to contend with bitter winters, but they do sometimes face extended dry periods, or droughts, when food can become scarce. During droughts, many will enter a deep sleep, called estivation (est-ih-VAY-shun), which is similar to hibernation.

Adult gymnures and hedgehogs typically live alone. They protect a territory by marking its edges with often-powerful scents and by threatening other adults to stay away with raspy hisses. If a predator approaches, hedgehogs take on a defensive posture by rolling into a ball and standing their spines on end—turning themselves into living pin cushions. Gymnures have no spines for protection and instead try to stay out of sight of predators as often as possible, hiding beneath piles of branches or leaves, among tree roots, or sometimes in burrows dug by other animals.

Adult gymnures and hedgehogs give up their solitary existence during mating periods, and the females welcome males with the same types of hisses they used earlier in the year to scare them away from their territories. Because of their spines, hedgehog mating can be tricky. To accomplish it, the female smoothes down her spines, so the male can approach without being hurt. After mating, the male leaves and returns to his solitary life. Females, on the other hand, must care for the two to five, blind and helpless babies now living in the nest. The young stay with the mother for five to seven weeks until they are ready to survive on their own.