Porcupines are unique mammals known for their sharp quills, which are modified hairs that help protect them from predators. These quills can easily detach when a predator tries to attack, making it difficult for the attacker to get close. Porcupines are primarily nocturnal and are often found in forests, where they climb trees and feed on leaves, bark, and fruits. There are two main types of porcupines: North American porcupines and Old World porcupines. North American porcupines are larger and have a more robust body, while Old World porcupines are generally smaller and have spiny fur. Both types are fascinating creatures that play important roles in their ecosystems.