Baby porcupines have soft quills that begin hardening about an hour after birth. Porcupines have strong, short legs and their feet have hairless soles to help it climb trees. Males are larger than females. Adult porcupines weigh around 20 pounds. The average body and head length is 25 to 36 inches and the average tail length is 8 to 10 inches.
The porcupine is a herbivore that eats leaves, twigs, bark and green plants like skunk cabbage and clover. Excellent swimmers, the air-filled quills help keep the porcupine afloat.
Fishers are a primary predator of porcupines, but quills have been found embedded in coyotes, cougars, bobcats, foxes, lynxes, bears, wolves and even Great Horned Owls. These predators kill a porcupine by biting its unprotected face or by flipping it over to expose the vulnerable underside. Primarily nocturnal, North American porcupines are active all year. Their summer diet consists of a variety of shrub and tree leaves. In winter, they feed on the cambium layer and inner bark of trees, and evergreen needles.
Their fondness for salt often leads them to roadways where salt has been sprinkled to melt winter ice. Around campsites, they will gnaw on anything smeared with salty sweat, such as canoe paddles, axe handles and saddles. A porcupine produces one offspring at a time.
Though the porcupines seem to be fully protected in their prickly suit of armor, there is one animal that has adapted to take advantage of a weakness in their shield.
While porcupines have many predators, including red fox, coyotes, wolves, bears, mountain lions, lynx, bobcats, eagles, and great horned owls, the fisher is a uniquely adapted one.
But for the fisher, quills do not seem to be such an obstacle. Unlike longer-legged predators, fishers are the same height as porcupines and are able to attack them face to face. Quills guarding its face from above are useless against attackers coming from below. The fisher is weasel-shaped, long and low to the ground, which gives it a clear advantage over the porcupine. It rapidly strikes the face of the porcupine in order to injure its prey.
Often, the attack can take over a half an hour until the fisher can inflict a lethal bite. A porcupine spends most of its time in trees, where it is safe from terrestrial assailants. All porcupines have long claws. These claws help them climb on both large tree trunks and surprisingly small branches. The palms and soles of porcupines have a pebbly surface and no fur.
Along with their keen sense of touch, this special texture on the hands and feet improves a porcupine's grip. Because they are so good at gripping trees, porcupines can even stay in trees using only their hind feet to hold on. This frees their forelimbs for use in eating. Roze, North American porcupines are special among their close relatives, because they are able to withstand cold.
No other porcupines are able to tolerate such cold temperatures. Male porcupines are larger than females. This is because bigger males are able to have more mates.
Because of this, they have more offspring than smaller males do. Sweitzer and Berger, North American porcupines, Erethizon dorsatum , have the northern most range of all porcupines. They are found throughout most of Alaska and Canada, in the northern part of the Great Lakes region, as well as throughout the west and northeast regions of the United States. Porupines in the forests of New York and Massachusetts, in the Great Basin Desert, and in the woodlands of Texas have been well studied.
Griesemer, et al. Porcupines use a variety of habitats. Because they are found throughout the continent of North America, porcupines can be found in many different climates, and at many elevations.
Porcupine habitat varies geographically. Porcupines live in open tundra, deciduous forest, and desert chaparral. In the Pacific Northwest, they spend most of their time on the ground. In New York, porcupines are found mostly in trees.
The amount of time porcupines spend on the ground depends on how much groundcover there is for foraging and for protection from predators. When ground cover is scarce, porcupines spend more time in trees. Because most predators of porcupines live on the ground, porcupines also spend a lot of time in trees where predator populations are large. Porcupines prefer to spend their winter rest time in in rock dens on the ground. When ground dens are not available, porcupines will choose trees as their resting positions.
Porcupines usually choose different trees for feeding and for resting. In eastern habitats, hemlock trees are often chosen for both resting and feeding. Hemlocks are preferred because they have very thick foliage, which helps the porcupine to stay hidden. Hemlocks are also sturdy trees with high nutritional value.
In southwestern Texas, porcupines both feed and rest in papershell pinyon pines, as well as in oaks and other hardwood species. Porcupines in the Rocky Mountains feed primarily on ponderosa pines, and rest in dens on the ground. Similarly, porcupines in the Great Basin use dens in rock outcroppings and juniper trees for cover in the winter.
They travel between dens and the areas near rivers to forage on tree bark. This travel makes them susceptible to predators. The mating system of porcupines is considered female defense polygyny. Successful males mate with many different females, but unsuccessful males don't mate at all.
Successful males defend a female from 1 to 4 days so that other males can't mate with her. Porcupines breed only once a year. Female porcupines attract many males. These males compete with each other to determine dominance. The dominant males are the ones who succeed in defending females from their rivals. These are the males who father offspring. Females maintain a territory, and defend it against other females. However, male territories usually overlap those of several females.
The territories of dominant males rarely overlap. Females all have similar sized territories. A male's territory usually gets bigger throughout his life. Females attract potential mates through scents and vocalizations.
Several males converge on an advertising female. Successful males have to compete for, and then defend, the female. Mating will only happen after a female has chosen a male and is receptive to him. Breeding occurs in October and November. Gestation in this species is days, after which a female gives birth to a single offspring. Newborns weigh between and g.
Young are nursed for about days. They become independent of their mothers at approximately 5 months of age, but are not sexual mature until the age of 25 months for females, and 29 months for males.
Roze, ; Sweitzer and Berger, Parental care is provided by the mother. Mainy, a mother provides her baby with food. For the first six weeks of a porcupine's life, its mother is always close by. They meet only at night. During the day the baby is hidden on the ground, while the mother sleeps in the trees. After six weeks, the baby porcupine follows the mother to feeding trees and waits for her at the bottom. Over the next couple months, resting positions and foraging distances show increasing separation between the young porcupine and its mother.
The mother continues to travel to the position of the baby every night, following landmarks and not scent trails back to the infant.
By mid-October the baby completely loses contact with the mother and is left to survive its first winter alone. The father spends no energy in the rearing of or caring for the offspring.
Males have little to no contact with their offspring.
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