A porcupine is a large rodent covered in sharp, pointed quills that protect it from predators. These quills are modified hairs, each one stiff and needle-like, with tiny barbs at the tip that make them painful to remove once they lodge in an attacker's skin. When threatened, a porcupine turns its back, raises its quills, and may even rattle them as a warning. If an animal gets too close, the porcupine can swing its tail, driving the quills into its attacker.

Despite old stories, porcupines cannot actually shoot their quills through the air. The quills detach easily when touched, which can create the illusion of shooting. A curious dog or coyote that sniffs too close may end up with a face full of quills, learning a painful lesson about respecting porcupines.

North American porcupines live in forests and spend much of their time in trees, eating bark, leaves, and twigs. They're slow-moving creatures that rely on their quills for defense rather than speed or aggression. A single porcupine can have over 30,000 quills covering its body, making it one of nature's most effectively armored animals.