The porcupine, sometimes called a quill pig, is a shy, gray-and-brown herbivore covered in barbed quills. Though most comfortable on the forest floor, a porcupine can climb trees adeptly to seek out leaves, bark, and insects for food. The giant porcupine is no less shy than its smaller kin, but these 5-foot-long specimens climb only the ancient old growth of deep forests. Both species are found only in temperate woodlands, though a giant porcupine prefers forests with less undergrowth where it can maneuver more easily.