1. Hedgehogs are not related to porcupines. They are actually most closely related to the mole.
2. Hedgehogs are nocturnal.
3. Hedgehogs do not "throw" their quills, meaning that if you are pricked by a quill it does not detach itself from the little hedgies body. Instead that have two muscles, one on either side of their body, that they use to "stand up" their quills when they are frightened.