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If you hear someone mention a porcupine, you probably instantly think of the many prickly spines that famously coat the sizable rodents' bodies. The porcupine realm is made up of about 23 species -- all spiky. Although these spikes -- or quills -- are totally different than standard hairs in many ways, they too grow back.
Porcupine quills serve important protective functions to the animals. When porcupines encounter trouble, they protect themselves via shoving their painful and pointy quills into the direction of their opponents. Scared porcupines' quills immediately protrude, although they're normally flattened against them. It isn't hard for the quills to loosen themselves from the porcupines and plant themselves directly and firmly into the skin of their enemies -- ouch. Although porcupines can push their quills onto their rivals, they don't have the ability to toss them their way.
Quills Grow Back
Luckily for porcupines, their quills do indeed grow back after falling off. Shedding is a normal process of porcupine quills, just as it is with standard hair. "Successor" quills often start emerging in the span of a mere few days after the earlier ones come out. New quills grow pretty rapidly. Until the quills are back to their full length, they usually grow approximately 1 millimeter for each couple of days. New and old quills constantly mingle on porcupines' bodies, which is why their lengths are rarely exactly the same. When developed quills come out of porcupines, bleeding typically doesn't take place. Their roots are already shut at that point. The whole growth process generally takes several weeks.
What Quills Are
Although quills might seem unusual in their spiky appearance, they're actually simply specialized hairs that are composed of keratin, the same protein your hair is made of. Quills, size-wise, are different across the various species of porcupines. Some porcupines have extremely long ones. Crested porcupines' (Hystrix cristata) quills are often close to 1 foot in length.
Numbers of Quills
Porcupines' quills appear almost all over their bodies, from their tails to their backs. The quills do not cover their lower portions. Porcupines are equipped with an abundance of the tough hairs -- often at least 30,000 of them. Quills often differ based on where specifically they're situated on porcupines' physiques. Thin and somewhat frail quills are usually seen by their heads. Their tails, on the other hand, are usually home to lengthier, broader quills.
- San Diego Zoo Animals: Porcupine
- National Geographic: Porcupine
- Messinger Woods Wildlife Care & Education Center: Species Profile - The Porcupine
- Texas Parks & Wildlife: Porcupines
- Yucky Animals in the Yard; Alix Wood
- Natural Materials; Jean DeMouthe
- Conservation of Cultural Heritage; Hanna M. Szczepanowska
- Animal Planet: Porcupines
- Minnesota Department of Natural Resources: Porcupine
- Oklahoma Department of Wildlife Conservation: Porcupine
- Tom Brakefield/Stockbyte/Getty Images