With needle-sharp quills, some longer than the average human forearm, porcupines sport one of nature’s most frightening defenses against predators. But a new study shows they can be fearsome killers as well . Researchers in Italy have found that the rodents can slay dogs, foxes, and even badgers. Scientists monitored porcupines in Tuscany for about 18 months. They identified four defenses that the animals employed, in order of increasing aggression: quill erection, tail rattling, stamping and growling, and backwards or sideways attacks. The porcupines never used the latter two in one-on-one encounters, but rather as last resorts when an individual was outnumbered, or if multiple porcupines were present and more likely to inflict serious damage. In one such case, two porcupines ran backwards, forcing a dog into their den, where they fatally impaled it with their quills. Other porcupines killed four other predators, two badgers and two foxes, over the study period; such deaths have never been previously recorded in scientific literature, the team reports in Mammalia.