If you're walking through the forest and you hear a rattling sound nearby, step lightly. You may be in the presence of a threatened porcupine. In the same way that rattlesnakes in the desert shake their tails before striking, porcupines may display and rustle their quills to warn a potential predator to back off. If the threat continues to advance, it may end up with a face full of these barbed hairs. And these small animals don't need to aim perfectly in order to poke predators as they're protected with 30,000 quills on average, covering their entire bodies except their faces, inner limbs and bellies.
Ranging across North America, except for the Southeastern and Great Plains states, porcupines generally live in forests full of cone-bearing trees. They're the only mammals in North America with quills [source: Feldhamer et al]. These rodents don't use their spiky tresses for hunting since they're herbivores, eating mostly inner tree bark and foliage. Instead, these quills serve mostly defensive purposes, protecting porcupines from predators and allowing them to put up a decent fight if challenged.
In addition to being used as actual weaponry, porcupine quills serve as part of the animal's elaborate warning system. They're marked with white pigmentation that contrasts with the porcupine's darker fur, making them more visible to any potentially threatening animals at night, when porcupines are most active [source: Feldhamer et al]. Also, these barbed hairs deliver an olfactory message when the rodent becomes perturbed. The porcupine's sebaceous glands produce an odor which is secreted into a patch of skin called the rosette, located on its lower back [source: Roze]. When angry, the quills atop the rosette emit a pungent hormonal odor. Other animals like deer have special hairs, referred to as osmetrichia, that perform similar scent-spreading tasks [source: Roze].
In addition to short, thick underfur, longer guard hairs and motion-sensitive vibrissae, or whiskers, porcupines have thousands of quills that lay flat when the animal is relaxed and stand on end when it feels threatened. Quills vary in size from half an inch to 4 inches (1.2 to 10 centimeters) long. Despite their appearance, quills are really specialized hairs. A quill consists of a follicle that attaches to the skin, a shaft with a spongy interior and the notorious barbed tip. If you look closely at the tip, you'll see multiple layers of barbs that cause the quill to embed deeper into a victim's skin after penetration.
But sometimes, porcupines can fall prey to their own defensive tricks.
How to Remove Porcupine Quills
Porcupines can be clumsy creatures. Since they eat tree bark, it isn't uncommon for them to fall occasionally from their arboreal buffets. So what happens when porcupines prick themselves? Porcupine quills are coated with antibiotic fatty acids that help speed up the healing process in case they pierce themselves [source: Roze et al]. The quills also have a specialized release mechanism that controls when a porcupine can actually discharge a quill because unlike a popular myth, they cannot shoot these barbed hairs at will.
This release mechanism is based on a loop of thick connective tissue that surrounds the quill follicle and binds it to the dermis under the surface of the skin. When the porcupine is relaxed, that tissue loosely holds the quill in place to keep it from lodging deep into the flesh, in case the animal falls on it. However, when porcupines grow tense (like when warding off a predator), the muscles surrounding that connective tissue pull it taut. If the quills are erect and experience an impact, the force from that contact drives the quill inward, slicing the tightened tissue and freeing the quill. Once the root of the quill is loose from the porcupine's skin, it can lodge into the predator's skin. A study on this release mechanism found that this process makes it nearly 40 percent easier for the quill to leave the porcupine's skin than if you tried to pull it out without any prior impact [source: Roze].
As mentioned earlier, once you get stuck with a porcupine quill, the barbs on the tip naturally drive it deeper into your skin. It requires significant force to remove this little gift. If you happen to be the unlucky recipient of a porcupine quill in the arm or leg, grab a pair of needle-nose pliers and prepare yourself for a pinch. The best way to remove porcupine quills is simply to pull them out. Because of those nasty barbs, you'll need to work firmly but delicately to prevent the quill from snapping off. In case that does happen (and you prefer not to have a doctor dig the barb out of your skin), you're not in much danger. The quills don't contain poison, and the barbed tip should work its way out of your skin eventually. The antibiotic coating on the quills also reduces the chance of primary infection [source: Gibbons]. But as you would with a large splinter, disinfect the area and apply antibiotic ointment to any open wound to ward off secondary infection.
Unless you make a habit of trolling about coniferous forests, your pet is more likely to get slapped by a porcupine tail than you are. Curious dogs in particular may get muzzles full of quills. If there are only a few stuck in your pet's body, you can remove them yourself, depending on the dog's temperament. If quills are inside Fido's mouth or throat, it's safer to call your veterinarian.
Even though a porcupine loses some of its quills, it can still strike again. The quills grow back after several months. To avoid getting poked, keep an ear out for their telltale rattle and your nose on standby for a suspicious stink the next time you're near their habitat.
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More Great Links
- Feldhamer, George A.; Thompson, Bruce Carlyle; and Chapman, Joseph A. "Wild Mammals of North America." JHU Press. 2003. (Oct. 1, 2008)http://books.google.com/books?id=-xQalfqP7BcC
- Gibbons, Whitt. "Porcupines Have a Point to Make." University of Georgia Savannah River Ecology Laboratory. Aug. 5, 2003. (Oct. 1, 2008)http://www.uga.edu/srel/ecoviews/ecoview030805.htm
- "Prehensile-tailed Porcupine." Smithsonian National Zoological Park. (Oct. 1, 2008)http://nationalzoo.si.edu/Animals/SmallMammals/fact-porcupine.cfm
- Roze, Uldis. "A facilitated release mechanism for quills of the North American porcupine." Journal of Mammology. Vol. 83, No. 2. 2002. (Oct. 1, 2008)http://cat.inist.fr/?aModele=afficheN&cpsidt=13678865
- Roze, Uldis; Locke, David C.; and Vatakis, Nick. "Antibiotic Properties of Porcupine Quills." Journal of Chemical Ecology. Vol. 16, No. 31. 1990. (Oct. 1, 2008)http://www.springerlink.com/content/x6vh04203r676774/
- Roze, Uldis. "Smart Weapons." Natural History Magazine. March 2006. (Oct. 1, 2008)