Here’s the “business end” of the Porcupine. Their rump and tail are covered with up to 30,000 quills. These are modified hairs; solid on both ends, hollow in the middle, and with a sharp barb on the end. They are loosely attached to muscles just under the skin. Porcupines cannot “throw” their quills but any predator that gets too close could get a very painful lesson from the swinging tail of the Porcupine.