What are the key differences between a porcupine and a hedgehog?

Here are three differences between a porcupine and a hedgehog: Size: Porcupines are significantly larger than hedgehogs. Quills/Spines: Porcupine quills are long, sharp, and can detach easily, while hedgehog spines are shorter, less sharp, and are firmly attached. Defense Mechanism: Hedgehogs typically roll into a tight ball for defense, whereas porcupines primarily use their quills by shaking them or backing into predators. That's 2 down. 3 left today — send the next one.