(Portland, OR) -- The Oregon Zoo is celebrating a milestone birthday for Nolina, an African cape porcupine. She's 20 years old, which is notable, since African cape porcupines seldom live past the age of 15 in the wild. Zookeepers credit her daily walks around the zoo, which they started five years ago, with keeping her healthy. African cape porcupines are the world's largest, growing up to two-and-a-half feet in length and weighing over 40 pounds, with foot-long quills. Contrary to legend, porcupines do not "shoot" those quills, but they will raise and fan them out, if they are frightened or excited.