Owls Aren't Wise and Bats Aren't Blind by Warner Shedd

guard hairs. A porcupine has an astonishing 30,000 quills to protect its back, flanks, and tail—an average of about 140 quills per square inch on much of its body! The face and underside lack quills, however, thereby giving porkies the animal equivalent of an Achilles’ heel, albeit one that few predators are able to take advantage of.

    Porcupine
    The quills vary in length; those on the back are the longest, while the shorter ones are located on the head and tail. The longest quills can span as much as five inches, but most measure about three inches. The majority of quills are white for much of their length—possibly to make the porcupine’s weapons highly visible and hence more threatening to a prospective predator—but a few are completely black. Each quill has an extremely sharp tip and is very loosely attached at its base; it hardly takes more than a touch to embed the sharp point in the flesh of an attacker, whereupon the quill easily departs from its very tenuous attachment to its owner.
    It’s widely believed that porcupine quills are equipped with tiny barbs, like those on a fishhook: they aren’t, although for all practical purposes they might as well be. Instead, the tip of a quill has diminutive scales, much like tiny fish scales. These overlap so that the raised edges point toward the rear and function in much the same manner as the barbs on a fishhook; once embedded in flesh, these scales make it very difficult and painful to remove a quill. In any event, to the animal or human painfully stabbed by a number of these miniature lances, the technical difference between barbs and scales is probably of no consequence!
    Because of the scales, lodged quills tend to work their way forward. There are numerous instances, in both humans and animals, of quills that have disappeared, worked forward, and, after a period of time, emerged at a considerable distance from the entry point. Occasionally, quills have been known to work their way into a vital organ and cause death. This is probably relatively rare, however; a greater danger is that an animal whose face and mouth are riddled with quills may be unable to hunt or eat properly, and thus may die of malnutrition.
    One myth about porcupine quills stems from the fact that their hard, tough exterior conceals a more or less hollow interior. The operative term here is “more or less.” Folk wisdom to the contrary, quills aren’t filled with air like a balloon, and hence don’t deflate when their posterior end is cut off. Instead, quills are filled with light, spongy material, and cutting the end of the quill off is no aid to removing it from a dog or other creature. Indeed, this tactic may even make matters worse, since it leaves less quill to grip with pliers or forceps, and may splinter the quill as well.
    Undoubtedly, the oldest, most enduring, and most widely believed myth about porcupines is that they can throw their quills. Just when and how this fiction began is buried in the mists of time. However, it most certainly was given great credence by that famous Roman, Pliny the Elder, who died in the cataclysmic eruption of Vesuvius that buried Pompeii and Herculaneum in A.D. 79.
    Pliny’s massive, thirty-seven-volume
Historiae Naturalis XXXVII,
published in A.D. 77, is riddled with scientific inaccuracies—men whose feet were turned the wrong way, winged horses, unicorns, and many other nonexistent marvels. Evidently, Pliny was an uncritical believer in the wide variety of fanciful tales that reached his ears, and one of these concerned the porcupine. In 1601, Englishman Philemon Holland, also a true believer, gave us this translation: “The porkpen hath the longer sharp pointed quilles, and those, when he stretcheth his skin, he sendeth and shooteth from him.”
    Perhaps the porcupine’s formidable tail has something to do with this myth. When an intruder approaches a porcupine too closely, the animal reacts by lashing its tail ferociously from side to side.