A porcupine when threatened turns its rear to the predator, erects its quills and begins swinging its tail like a club.

Something occurred to me recently that I’d never thought of before: porcupine birth. Yeah. Ouch, right? Covered head to tail in sharp quills—that’s gotta pose a serious problem in the delivery room.

Porcupettes are born with soft, flexible quills that harden within hours, protecting both mother and baby. Baby porcupines are precocial, able to walk almost immediately and begin climbing within days ...