Erethizon dorsatum-North American Porcupine

© Stephen DeHart – (INaturalist)

~Add summary paragraph~

## **Size**

Head and Body 26-37 in. (65-93 cm), Tail 6-12 in. (15-30 cm), Weight 7-40 pounds (3-18 kg). They are larger in the West than the East.

## **Description**

The North American Porcupine is our area’s only mammals with quills. It is a large and heavy-bodied rodent covered in yellowish quills on its head, rump, and upper surface of tail. Guard hairs are typically blackish in the eastern regions, while mostly yellowish in the West. It has four claws on its front feet, while its hind feet have five claws.

## **Subspecies**

Three subspecies are found in the southern USA.

* ***Erethizon* *dorsatum* *bruneri* (Swenk, 1916)**

Found in the Great Plains east of the Rockies, into western Oklahoma and northwest Texas.

* ***Erethizon* *dorsatum* *couesi* (Mearns, 1897)**

Found in western Texas, New Mexico, and central Arizona.

* ***Erethizon* *dorsatum* *dorsatum* (Linnaeus, 1758)**

Found in Canada east of the Territories of Yukon and British Columbia (excluding Labrador and Newfoundland) south to north-eastern and north-central USA to Virginia and West Virginia.

## **Range**

This species has a wide distribution from Alaska and Canada south to Northern Mexico. It is absent, however, from much of the Southeast, Midwest, and southern California.

## **Range in South**

In the South, the North American Porcupine is limited to the Appalachians of Maryland, West Virginia, and Virginia in the East, and the western regions of Texas and Oklahoma in the West. It formerly ranged further south in the Appalachian mountains as supported by fossil records from the Holocene period (~1,000+ years ago) in Alabama, Tennessee, and North Carolina.

## **Habitat**

Most often found in deciduous and coniferous forests in mixed softwood and hardwood communities. However, they may also be found in non-forested areas such as grasslands and agricultural habitats.

## **Behavior**

North American Porcupines do not hibernate through the winter, and are active throughout the year. They are typically nocturnal, but may be active any time of the day or night. These rodents are normally solitary, but may share a den in winter months, with up to eight per den. If a den is not available, they may spend the winter in a tree, defending it from intruders. They may forage in groups of up to 20 in winter months.
 While they can swim across small bodies of water, they tend to avoid swimming. However, they are great climbers, climbing trees for food and protection. Both males and females are territorial, with males being more-so. The individuals know their range well and tend to not stray far from it. They are known to vocalize, with some sound they make including moans, whines, grunts, coughs, squeaks, mews, snorts, barks, owl-like hoos, and shrill screeches. The males are known to chatter their teeth when frightened. Their courtship is described as elaborate, filled with much vocalization.

## **Reproduction**

Females of this species reach sexual maturity at around 2 years of age, while males reach sexual maturity closer to 2.5 years of age. North American porcupines mate between autumn and early winter. Gestation is approximately 210 days, though it ranges from 205-217. In April-June, a single young is born, however, there are a few records of more than one young being birthed. The newborns weigh in at 12-22.5 ounces. The young are born with their eyes open and their incisors, premolars, and molars erupted. Upon birth their quills are well-formed, yet soft, but they will harden within an hour of birth. Soon after birth, the young can climb and undertake typical defensive posture. At 1-2 weeks the young can survive on vegetation, but they will remain close to their mother and nurse. The young become independent from their mothers approximately 5 months after birth.

## **Diet**

In summer, North American porcupines have a varied diet including roots, stems, leaves, berries, catkins, seeds, flowers, nuts, aquatic plants, and grasses. While in winter they primarily feed on the inner bark of trees and the needles of evergreen trees. Porcupines that live in non-forested, open habitats may forage on grasses, crops, and shrubs and trees planted in yards or nearby roadways. They may cause damage by gnawing at trees in forests and orchards, crops, ornamental trees, rubber tires, plumbing, and woodpiles.

## **Predation and Lifespan**

Even with their elaborate defense system of quills, they still fall to predators occasionally. Some animals recorded preying on these porcupines include red foxes, bobcats, coyotes, wolves, domestic dogs, cougars, and great horned owls. But one predator has a bigger predatory impact on these porcupines, the fisher. Fishers have been reported to cleverly and cautiously attack the porcupines to avoid the quills, and ultimately flip the porcupine onto its back to attack the unprotected underside of the porcupine. Predators typically hunt and kill porcupines in open environments. North American Porcupines typically live 5-6 years in the wild, but they have been reported to reach ages of up to 18. Their lifespan is likely limited by the life of their gnawing teeth with individuals over 12 years of age showing decreasing eating and being smaller in size. Humans are also responsible for killing this species.

## **Status**

While listed as least concern by IUCN, this species had faced major reductions in populations in the eastern USA. This porcupine has been extirpated from its former range in Tennessee, Alabama, and North Carolina since before 1000 A.D. This population's disappearance was likely caused by the gradual rising of temperatures throughout the Holocene and/or the decline in hemlock trees (crucial for refuge and food in eastern porcupines) in the Appalachians, which weakened the population of porcupines in that area. The remaining individuals were then likely wiped out from human hunting. It is considered by NatureServe to be critically imperiled in Virginia, and Vulnerable in West Virginia, Maryland, and Oklahoma. However, its population appears to be secure in Texas.

## **References**

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 [Reid, F. A. (2006). A field guide to mammals of North America. Houghton Mifflin Company.]
2. ↑ [Whitaker, J. O. (1996). The Audubon Society Field Guide to North American mammals. Knopf.]
3. ↑ [ITIS. (2023). Erethizon dorsatus Linnaeus, 1758. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search\_topic=TSN&search\_value=825295#null]
4. ↑ 4.0 4.1 4.2 4.3 [Wilson, D. E., & Ruff, S. (1999). The smithsonian book of north american mammals. Smithsonian Institution Press in association with the American
Society of Mammalogists.]
5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 [GBIF. (2022). Erethizon dorsatum Linnaeus, 1758. https://www.gbif.org/species/6066824]
6. ↑ 6.0 6.1 6.2 6.3 6.4 [Whyte, T. R. (2010). Erethizon dorsatum (L.) (American Porcupine) Skeletal Remains from the Charles Church Rockshelter, Watauga County, North ‎ ‎ ‎ Carolina. Southeastern Naturalist, 9(4), 821–826. https://doi.org/10.1656/058.009.0416]
7. ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 7.12 7.13 7.14 7.15 7.16 7.17 7.18 7.19 7.20 7.21 7.22 7.23 7.24 7.25 7.26 7.27 [Best, T. L., & Dusi, J. L. (2014). *Mammals of alabama*. University of Alabama Press.]
8. ↑ 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 8.10 [Weber, C. (2004). Erethizon dorsatum (North American porcupine). https://animaldiversity.org/accounts/Erethizon\_dorsatum/]
9. ↑ [IUCN (2016). Erethizon dorsatum. https://www.iucnredlist.org/species/8004/22213161]
10. ↑ 10.0 10.1 [NatureServe Explorer. (2023). Erethizon dorsatum. https://explorer.natureserve.org/Taxon/ELEMENT\_GLOBAL.2.101195/Erethizon\_dorsatum]