The porcupine is a timid rodent whose unique method of self-defense often causes problems for inquisitive animals. Unable to travel very fast to run from danger, he defends himself against predators with sharp spines that grow as part of his hair coat. He has about 30,000 of these multi-barbed quills that re-grow when lost or broken off. Bobcats and cougars are his main enemies, flipping the rodent over and biting the unprotected underside.
When threatened or frightened, he bristles with needle-sharp quills he can raise or flatten at will. He curls into a ball to protect his face, belly and the underside of his tail, which have no spines. His quills are very sharp and only loosely attached to his skin, easily embedded in the flesh of a predator. If pestered by a dog or a curious horse or cow, he may swat with his tail, driving quills deep into his tormentor’s flesh. He cannot “shoot” his quills; a quick slap of the tail is enough to stick them in any animal that gets too close, or drive them through a heavy glove. A dog or coyote with a face full of quills may starve to death because of difficulty eating.
Quills stuck into flesh tend to keep working deeper because of the victim’s muscle action. The black portion of the quill is covered with a layer of small, sharp barbs that look like fish scales when viewed under a microscope.