New World porcupines

(Erethizontidae)

Class Mammalia

Order Rodentia

Suborder Hystricognathi

Family Erethizontidae

Thumbnail description
Stocky animals distinguished by many sharp spines that cover much of their upper bodies and tails

Size
Adults range from about 15.5–51 in (0.4–1.3 m) and about 6.5–22 lb (3–10 kg)

Number of genera, species
5 genera; 19 species

Habitat
Mainly arboreal throughout forests, although one species extends into deserts

Conservation status
Not threatened

Distribution
North, Central, and South America, from Canada and Alaska to Argentina

Evolution and systematics

Although both Old World and New World porcupines exist, the New World family Erethizontidae is actually more closely related to pacas, agoutis, and other cavy-like rodents than to the Old World porcupine family Hystricidae.

This family requires additional research before its placement is clear. Until that work is completed, however, this chapter will use the following classification of genera and species:

• Chaetomys—C. subspinosus (this species was thought to be extinct until it was rediscovered in 1986)
• Coendou—C. bicolor, C. ichillus (described as new species in 2001), C. koopmani (described as new species in 1992), C. melanurus (sometimes identified as Sphiggurus insidiosus), C. pallidus, C. paragayensis (sometimes identified as S. spinosus), C. prehensilis, C. pruinosus (sometimes classified as S. vestitus), C. roosmalenorum (described as new species in 2001), C. rothschildi, and C. sneiderni
• Echinoprocta—E. rufescens

• Erethizon—E. dorsatum
• Sphiggurus—S. insidiosus, S. mexicanus (sometimes classified under the genus Coendou), S. spinosus, S. vestitus, and S. villosus

Scientists are still grappling with this family's phylogeny and taxonomy, particularly since some of the species listed above are known from only one or a few specimens. Some of the questions involve the genus Chaetomys, which has at times been placed in the family Erethizontidae or the family Echimyidae; the genus Sphiggurus, which is often grouped as a subgenus of Coendou; and C. rothschildi, which is considered by some to be a subspecies of C. bicolor. Many other questions also remain. Phylogenists tend to agree that the erethizontids likely spread from South America to North America, but they continue to puzzle over whether the Erethizon genus branched from the Coendou genus or a now-extinct species, known as Steiromys.

Physical characteristics

Porcupines are best known for their sharp quills. Spines cover much of a porcupine's dorsal surface from the back of the head to the tail, although a few, such as C. prehensilis and S. mexicanus, are naked on at least a portion of their tails.

Both of these species have prehensile tails, which they use in climbing. The spines are evident on many species, including E. dorsatum, but mostly hidden beneath long fur on others, such as S. mexicanus and S. spinosus, and in most young porcupines of various species. The claws are long and curved.

Porcupines in general are stocky with a blunt muzzle and small eyes. Their short, strong limbs and clawed, four-toed feet make them well-suited for climbing. The ears are small and round, almost concealed by the hair, which also covers the spines. The shoulders are humped, making the back look arched. The short legs are bowed, and the animal stands bear-like with its entire foot planted firmly on the ground. The porcupine is one of the largest rodents in North America, second only to the beaver. Adult porcupines range from about 15.5 to 51 in (0.4–1.3 m), with tails that can stretch about a quarter to more than a half of the total length. Coendou, Chaetomys, and Sphiggurus species have bulbous noses.

Porcupine longevity averages 15 years in the wild and some 21 years in the zoo.

Distribution

The majority of the species occur in South America, from the northern tip of the continent to northern Argentina and Uruguay. A few species reside further north into Central and North America. E. dorsatum is the northernmost species with populations existing well into Canada.

Habitat

These are primarily forest animals, dwelling in rainforests, as well as deciduous and coniferous woods. A few, such as C. prehensilis, are found in plantations and other cultivated areas. E. dorsatum frequently shares its forests with humans, and is often seen dead along roadsides as a traffic victim.

Behavior

Folk stories of porcupines throwing their quills are rampant, but they are untrue. This animal can impale an attacker with its easily detachable spines, but it cannot launch them. Normally, their quills—actually modified guard hairs—lie facing backward on the body. Under duress however, the animal erects the quills, which can reach 4 in (10 cm) long in the North American porcupine (E. dorsatum), and becomes a

formidable pincushion with spines jutting out in various directions. The porcupine may then remain stationary in a defensive pose, or may charge the antagonist. North American porcupines are also known to lash out at predators by quickly batting at them with their quill-laden tails. In all cases, once the quill enters the attacker's body, its barb lodges and the quill lets loose from the porcupine. Although the quills are not poisonous, they are painful and can cause serious damage to internal organs and sometimes death.

Little is known of the habits of many erethizontids, particularly the South American species. However, New World porcupines are presumably all nocturnal and arboreal, spending their days sleeping in trees or in ground-level hideaways. Some, like the thin-spined porcupine (C. subspinosus), spend the bulk of their nights resting, too, with most of their activity centered around feeding. Mating behaviors in the wild are best known for E. dorsatum, and are described in the separate species account.

Although porcupines are basically solitary, several sometimes share the same winter den. The winter territorial range is small, averaging some 12 acres (5 ha), but in summer it is larger, increasing to up to 35 acres (14 ha). Population densities fluctuate from year to year, and may range from one to 10 animals per 0.4 mi² (1 km²). Although not territorial, porcupines sometimes defend their winter feeding grounds from other species. Porcupine trails on snow are easily identified by the marks made by spines on the edge of the trail. Porcupines do not make a nest or burrow; they den in rock crevices or tree hollows.

Porcupines may seem aloof and unconcerned about danger, but should an enemy start to approach, a porcupine will back down flicking and lashing its tail. During confrontations, a porcupine will also chatter its teeth. Otherwise porcupines are mainly uncommunicative animals. The female may nose her young with gentle grunts and whines. Only in the mating season do porcupines become vociferous and create a variety of moans, screams, grunts, and barks.

Feeding ecology and diet

New World porcupines typically prefer fruits and seeds, but when these are limited, they are known to dine on leaves and bark. Sphiggurus insidiosus and S. spinosus also eat ant pupae and roots. In all species, feeding occurs at night during the porcupines' nighttime feeding forays.

Reproductive biology

Little is known of the reproductive biology of many erethizontids, particularly the South American species. It appears, however, that female porcupines are generally either pregnant or are lactating for the vast majority of their lives. Gestation commonly lasts about 200 days, after which the female mates almost immediately. She continues lactating for her newborns for approximately eight to 12 weeks.

Each pregnancy commonly results in one precocious offspring, which is born with fur and soft quills that harden quickly. The young generally reach adult size in about a year, and become sexually mature at about 1.5 to 2.5 years old. Coendou young have a soft orange color, significantly different from that of the adult species. All are precocious.

Conservation status

Many of the South American species are rarely seen, but that may be due in part to surveying difficulties presented by geographic distribution combined with their nocturnal and arboreal habits. Some, however, appear to have undergone population declines, although none of the New World porcupines is listed by the IUCN as threatened. The thin-spined porcupine, for example, has experienced a severe habitat reduction due to forest clearing, and was thought to have become extinct in the mid 1900s, until an individual was discovered in 1986.

Significance to humans

Some are hunted for meat. The quills of some species are used in artwork.

Species accounts

List of Species

North American porcupine

Erethizon dorsatum

subfamily

Erethizontinae

taxonomy

Erethizon dorsatum (Linnaeus, 1758), Quebec, Canada. Seven subspecies.

other common names

English: Canadian porcupine, quillpig, pricklepig, quiller; French: Porc-épic; German: Urson, Baumstachelschwein; Spanish: Puercoespín.

physical characteristics

Adults can reach nearly 39 in (1 m), with the tail making up a fifth to nearly a third of that total. Body weight is generally less than 26 lb (12 kg), but a particularly large male can top 33 lb (15 kg). Adults have stiff, black or dark-brown dorsal hair, interspersed with mostly white quills at the head, rear of the body, and on the tail. In all, an adult may have more than 30,000 barbed quills covering its dorsal body. The belly is quill-free and woolly. The young are more camouflaged with a nearly all-black head, back, and tail, and short, though still sharp, quills. Females have two pairs of mammae.

distribution

Most of Canada except the far north-central regions, and most of the western half of the United States as well as the north-central and northeastern states. It also extends into the northern edge of central Mexico.

habitat

Mainly arboreal animals that are common to forested areas, but occasionally also exist in open areas and even deserts, provided a water source is nearby.

behavior

The most temperate member of the family, this nocturnal species will occupy winter dens, which are commonly hollow trees and logs, or gaps beneath rocks. More than one porcupine may share a den, particularly when available denning locations are low in number. Studies conflict over whether severe weather may also prompt den-sharing. Some individuals do not den, instead spending their winters resting in trees.

Other than the group denning behavior, porcupines are generally solitary animals for much of the year. Although they are not normally territorial, an individual may defend a feeding site if resources are limited.

During the breeding season, females produce olfactory and auditory clues that indicate their readiness to mate and attract males. Two or more males may fight with one another over the opportunity to mate with a female. These battles can lead to quill impalements and other injuries. In an unusual courtship ritual, males will sometimes soak females with streams of urine while standing on their hind limbs facing the female. The purpose of the behavior is unknown. When the female is ready to mate, she indulges in a kind of dance with the chosen male, where they both rise on their hind feet to embrace, all the while whining and grunting loudly. Sometimes they place their paws on each others' shoulders and rub their noses together; then they may cuff each other affectionately on the head and finally push one another to the ground.

feeding ecology and diet

Porcupines are vegetarians, dining on foliage for much of the year and turning to the inner bark of oaks and pines in the winter months. They are also known to eat seeds, fruits, nuts, berries, and plant stems. Their chisel-like teeth scrape away the tougher, outer bark, then slice off even bits of inner bark for consumption. Cellulose-eating bacteria in the porcupine's gut assist the digestion of plant material. Mothers and young feed together, but they are otherwise solitary feeders. Feeding generally occurs at night, but occasionally they will feed during the day.

Their primary predators include fishers and mountain lions, although lynx, bobcats, coyotes, red foxes, wolves, wolverines, and even great horned owls will occasionally disregard the quills and attack porcupines.

During winter porcupines do not hibernate. However, they do not usually move far and feed within 300 ft (91 m) of their dens. During snow or rain they remain in the den or, if out feeding, sit hunched in a tree, even during subzero weather, until the weather improves. When the weather is dry in winter, they feed at any time of the day or night, but during the rest of the year they are nocturnal despite the weather. In summer, porcupines range farther from the den, often searching for food up to 1 mi (1.6 km) away. As well as these daily movements within the home range, there may be seasonal movements between winter denning areas and the summer feeding areas. In mountainous country, the porcupines will often descend during the winter along well-defined paths marked by debarked trees. In the spring, they return up the mountainside to summer feeding areas.

reproductive biology

Polygynous. Mating typically occurs only once a year in the fall, during a period of eight to 12 hours when the female is receptive. The female has a copulatory plug and if she does not become inseminated, she may mate again a month later. One young per female per pregnancy is the norm, two is rare, and gestation takes about seven months. The young weigh about 1 lb (450–490 g) at birth, and have both spines and fur. They grow quickly, doubling their weight in the first two weeks, but remain with the mother at least until the early fall when lactation ends. Juvenile females then disperse, but juvenile males may move in and out of the mother's range for months and even years. They attain sexual maturity at about 1.5 years and typical longevity is of the order of some 15 years.

conservation status

Not threatened.

significance to humans

The quills were once highly regarded among Native American populations, and used both in artwork and as a medium of exchange. These populations also hunted porcupines for meat during lean times. Currently, porcupines are generally seen as pests that gnaw through plywood and nearly anything salty, and damage homeowners' trees.

Prehensile-tailed porcupines

Coendou prehensilis

subfamily

Erethizontinae

taxonomy

Coendou prehensilis (Linnaeus, 1758), Pernambuco, Brazil.

other common names

French: Cuandu; German: Greifstachler, Cuandu; Spanish: Coendú grande, puerco-espín.

physical characteristics

An adult can range from about 3 to 4 ft (0.9–1.2 m) in length with half of that total in the tail, and about 9–12 lb (4–5.5 kg) in weight. Grayish to yellowish brown, mainly short-spined porcupine with a typically whitish face and small, black, and long, prehensile tail. The last third of the tail is unspined on its upper surface, providing a smooth contact point for wrapping around even thin branches. The long-clawed toes also aid its arboreal lifestyle. The young are uniquely orangish brown to brown with longer fur that somewhat hides the spines.

distribution

Eastern South America from eastern Venezuela and Trinidad to northeastern Argentina and Uruguay.

habitat

Typically found in vine-covered rainforests, but also occurs in farmed areas, gardens drier forests near a water source.

behavior

Prehensile-tailed porcupines spend the bulk of their time high in the trees, but since they do not leap from tree to tree, they travel from trunk to trunk on the ground. They normally move rather slowly, but can speed up if necessary. The long, prehensile tail combines with padded, clawed feet to make them excellent climbers. During the day, they sleep in a supportive clump of vegetation in the canopy.

Adults are typically solitary animals, but they do coexist peacefully with conspecifics on occasion. When threatened by a predator, they take on a defensive pose, sometimes rolling into a ball and raising their quills, and will occasionally lunge at an attacker with spines erect. Other displays include foot-stomping, spine-shaking, and threatening snarls and grunts. They also call back and forth with one another via long, moans. During breeding periods, the male commonly sprays urine on the female. He also will occasionally spray newborns.

feeding ecology and diet

These nocturnal, sometimes late-day, feeders are vegetarians, commonly dining on fruits and seeds, but also stems, leaves, roots, and bark.

reproductive biology

Little is known about mating interactions. Reproduce about every seven months. Although no species-wide seasonal schedule exists, births in some areas spike during the rainy season. Following a gestation period of 195 to 210 days, a female will have one offspring per year, after which she almost immediately mates again. The young are precocial, weaning in about three months, and reaching adult size at about 11 months old and sexual maturity at approximately 19 months.

One female of the species is reported to have produced 10 litters in 8.5 years and still was reproductively active at an estimated age of 11.5 years. A captive C. prehensilis lived for 17 years and four months.

conservation status

Not threatened.

significance to humans

Minor use as food. Sometimes regarded as a pest in agricultural areas.

Bahía hairy dwarf porcupine

Sphiggurus insidiosus

subfamily

Erethizontinae

taxonomy

Sphiggurus insidiosus (Lichtenstein, 1818), Bahía, Brazil.

other common names

French: Porc-épic arboricole nain, porc-épic laineux; German: Wollige Greifstachler; Spanish: Coendú, ouriço cacheiro.

physical characteristics

Although few specimens exist, they are believed to range from about 24 to 31 in (60–80 cm) in total length with a tail about a third to two-fifths of that length, and to have a body weight of about 2.6–3.3 lb (1.2–1.5 kg). Nearly completely dark-brown porcupine with spines that are concealed beneath thick, soft fur. The spines are whitish at the base, becoming brown distally, sometimes with orangish tips. The prehensile tail is slightly darker than the body, and is without spines or fur for its last third. Reports exist of white forms of this species. Young look similar to adults.

distribution

East-central to northeastern Brazil.

habitat

Primarily evergreen forests.

behavior

Sightings are limited, but probably nocturnal and arboreal.

feeding ecology and diet

A mainly herbivorous animal that eats fruits and roots, but will also eat any pupae.

reproductive biology

Little known, but a typical litter likely numbers one. Young are precocial, born with hair and soft quills, which quickly stiffen to provide a level of defense.

conservation status

Not threatened.

significance to humans

None known.

Mexican hairy porcupine

Sphiggurus mexicanus

subfamily

Erethizontinae

taxonomy

Sphiggurus mexicanus (Kerr, 1792), Mexico.

other common names

French: Porc-épic arboricole du Mexique, porc-épic préhensile; German: Mexicanische Baumstachler; Spanish: Puerco espín.

physical characteristics

Adults range from 21.5 to 31.5 in (55–80 cm) with a tail about a third to two-fifths of that total length, and weigh about 3–5.5 lb (1.5–2.5 kg). Dark brown to black porcupine with fur that covers most of the long spines on the body. The head is marked by yellowish spines that are visible through the fur, and by light-colored fur tufts near each ear. Like S. insidiosus, S. mexicanus has a prehensile tail that is naked distally. Young look similar to adults.

distribution

Southern Mexico to western Panama.

habitat

Favors high-elevation forests, but occasionally found in lowland habitats.

behavior

Nocturnal and arboreal animals that spend their days sleeping in vegetation among branches, in tree hollows, or in bamboo undergrowth, although some evidence suggests they might also utilize dens and caves. A usually solitary animal, males will fight with other males, but will tolerate females.

feeding ecology and diet

Prefers fruits and seeds, but also eats leaves and buds.

reproductive biology

Little known, but a typical litter likely numbers one. Young are precocial, born with hair and soft quills, which quickly stiffen to provide a level of defense.

conservation status

Not threatened.

significance to humans

Meat is used for food.

Resources

Books

Eisenberg, J. Mammals of the Neotropics: The Northern Neotropics. Vol. 1. Chicago and London: University of Chicago Press, 1989.

Emmons, L. Neotropical Rainforest Mammals: A Field Guide. Chicago and London: University of Chicago Press, 1990.

Redford, K., and J. Eisenberg. Mammals of the Neotropics: The Southern Cone. Vol. 2. Chicago and London: University of Chicago Press, 1992.

Reid, F. A Field Guide to the Mammals of Central America and Southeastern Mexico. New York: Oxford University Press, 1997.

Roze, U. The North American Porcupine. Washington, DC: Smithsonian Institution Press, 1989.

Wilson, D., and D. Reeder. Mammal Species of the World, A Taxonomic and Geographic Reference. 2nd ed. Washington, DC: Smithsonian Institution Press, 1993.

Wilson, D., and S. Ruff, eds. The Smithsonian Book of North American Mammals. Washington, DC: Smithsonian Institution Press, 1999.

Periodicals

Chiarello, A., M. Passamani, and M. Zortea. "Field Observations on the Thin-spined Porcupine, Chaetomys subspinosus (Rodentia; Echimyidae)." Mammalia 61 (1997): 29–36.

Griesemer, S., R. Degraaf, T. Fuller, and R. Degraff. "Denning Patterns of Porcupines (Erethizon dorsatum)." Canadian Field-Naturalist 110 (1996): 634–637.

Handley, C., and R. Pine. "A new Species of Prehensile-tailed Porcupine, Coendou Lacépède, from Brazil." Mammalia 56(1992): 237–244.

Roberts M., S. Brand, and E. Maliniak. "The Biology of Captive Prehensile-Tailed Porcupines, Coendou prehensilis." Journal of Mammalogy 66 (1985): 476–482.

Voss, R., and M. Da Silva. "Revisionary Notes on Neotropical Porcupines (Rodentia: Erethizontidae). 2. A Review of the Coendou vestitus Group with Descriptions of Two New Species from Amazonia." American Museum Novitates 3351(2001).

Leslie Ann Mertz, PhD