Porcupine

Agile and armed, although they may seem slow, a porcupine is quick to make its point with its defensive quills. Porcupines do not throw or cast their quills into a potential predator; instead, quills penetrate a predator's body on contact with the porcupine's prickly body. The more than thirty thousand quills on a porcupine's back and sides are actually modified hairs (one of the characteristics of mammals). Other common names of porcupines are quillpig and pricklepig. North American porcupines are arboreal or semiarboreal, spending much of their day climbing trees and consuming tree bark. These herbivores ingest a variety of plant materials, from buds to roots. On occasion, porcupines may eat shed antlers of deer or elk for the various minerals, such as calcium, that they contain. Second in size only to the beavers in the class Rodentia, adults porcupines weigh between four and six kilograms, although much larger ones have been reported. The length attained by adults ranges from about sixty to one hundred centimeters. While color variations occur, most individuals have dark colored pelage. Porcupines are mostly nocturnal, butmaybe observed during the day either on the ground or in trees.

Porcupine Life Cycle
Adult porcupines are solitary mammals for most of the year, except during the breeding season, between September and November. Female porcupines begin reproductive activities at about 1.5 years of age. It is common to find several males around a female during her brief (eight- to twelvehour) time of receptivity. Mating is brief and occurs on the ground, with the female raising her tail over her back. After the male has inseminated her, each porcupine goes its separate way. Usually only one porcupette, as the young are sometimes called, is born after the lengthy gestation period.Weighing between four hundred and five hundred grams at birth, newborn porcupines are quite precocial. Their eyes are open and their quills are present, as are their incisors and premolar teeth. Although capable of consuming vegetation within a week of birth, the young are nursed by their mother through the summer months. Porcupines consume the inner bark of trees and shrubs, especially in the fall and winter when the plants on the ground are becoming dormant or dying. It is easy to observe porcupine feeding sites in the forests by observing the limbs and trunks of trees. If the outer bark has been stripped away, the whitish colored areas beneath are quite apparent. During the spring and early summer, porcupines spend more time on the ground feeding on tender shoots and buds of emerging plants. While their vision is not acute, their olfactory (smell) and auditory (hearing) senses are well developed. Some researchers have reported observing porcupines standing up on their hind legs and sniffing their surroundings. If a porcupine detects a potential predator, it will form a defensive posture of lowered head and back, at the same time raising the tail for swinging. The heavy muscular tail can drive quills deep into a predator's face and head.