Porcupine facts!

Old World Porcupines and New World Porcupines are not closely related. Their similar traits are the byproduct of convergent evolution (two different species figured out a similar strategy).

Old World Porcupines tend to be much larger than the ones in the Americas, and live almost exclusively on the ground. They make their homes in burrows, and eat tubers and worms. New World Porcupines are smaller, and can climb trees. They can make their homes both in burrows on the ground, and in hollows within trees. They are more diverse in their diet - eating plenty of small animals and vegetation alike.

Old World Porcupines have differentiated fur/quills in the front/back respectively. Meaning old world porcupines have fur in the front, and quills in the back. They curl up, or back towards whatever threat they are encountering as a defense. New World Porcupines have undifferentiated fur/quills, meaning the fur and quills are mixed together - the entire backside of the animal has quills mixed with the fur.