The name porcupine refers to both the hedgehog and the porcupine (Hystrix cristata). The latter is a rodent whose spines have a structure that varies according to the areas of the body in which they are found: hairs with a rigid tip, real spines up to 40 cm long and hard bristles over 20 cm long. The bristles have such stiff and sharp ends that in some African tribes they are used for arrowheads. Illustrious figures such as Aristotle and Shakespeare argued that porcupines are able to launch their spines to defend themselves. But it's not true. It happens, rather, that when they are excited, the porcupines raise their backs. The spines, agitated and beaten against each other, produce a tinkling and threatening sound. In this circumstance, due to muscle contractions, those not well implanted in the skin can break off with such violence as to stick, at times, deeply into the wood or trousers of the victim. It is common to find detached or fallen spines on the ground. From this it seems to derive the legend of the porcupines who throw their "arrows".