The Crested porcupine (Hystrix cristata) is the largest rodent in Italy. Its aspect is unmistakable: it has white and black quills on the back, up to 30-40 cm long. There are people who believe that porcupines can throw their quills, but this is a popular belief. When porcupines sense danger they erect and shake quills, which makes them look larger than they are. If threatened, the porcupine turns its back to the attacker by approaching "in reverse gear" and can leave its opponent stuck with spines which sometimes cause serious wounds. Italy is the only European country where the porcupine lives. Outside of Italy, it can only be found in North Africa and Sub-Saharan Africa. The reason is not yet clear, but the most widespread opinion among scholars is that the porcupine was imported into Italy by the ancient Romans, as food.