PORCUPINES ARE WALKING PINCUSHIONS. Their permanently unkempt hairdo is actually a protective fortress of some 30,000 quills. But their body armor can be a liability, too - porcupines are known to accidentally quill themselves. "They're big and dopey and slow," said Tim Bean, an ecologist at California Polytechnic State University who has collared porcupines as part of his research. They waddle from tree to tree, usually at night, to snack on foliage or the nutrient-rich inner layer of bark.