Porcupines are large rodents known for their unique quills, which are sharp spines that cover their bodies. These quills serve as a defense mechanism against predators. When threatened, a porcupine can raise its quills and may even release them if touched, although they do not shoot them as commonly believed. There are two main types of porcupines: North American porcupines and Old World porcupines. They are primarily nocturnal and herbivorous, feeding on leaves, bark, and fruits. Porcupines are found in various habitats, including forests, grasslands, and deserts, across different continents.