Depending on the species, the gestation period is 35–58 days. The average litter is 3–4 newborns for larger species and 5–6 for smaller ones. As with many animals, it is not unusual for an adult male hedgehog to kill newborn males.
The hedgehog’s dilemma is based upon the apparent danger of a male hedgehog being injured from a spine while mating with a female hedgehog. It is believed that the closer two animals are to each other, the greater chance they may hurt one another. However, this is not an issue for hedgehogs as the male’s penis is very near the center of its abdomen (often mistaken for a belly button) and the female has the ability to curl her tail upward to the point that her vulva protrudes behind the rest of her body. As such, the male doesn’t have to get completely on top of the female when mating.
Hedgehogs have a relatively long lifespan for their size. Larger species of hedgehogs live 4–7 years in the wild (some have been recorded up to 16 years), and smaller species live 2–4 years (4–7 in captivity), compared to a mouse at 2 years and a large rat at 3–5 years. Lack of predators and controlled diet contribute to a longer lifespan in captivity.
Hedgehogs are born blind. Many believe that they are born without quills, which develop in the following days. However the quills are easily visible within hours of birth. The infants are born with quills beneath the skin, like pimples, and pass the skin after they have been cleaned.