Mammals

Porcupine

Hystricidae and Erethizontidae · also called porcupines, quill pig

Least Concern → herbivore Temperate forest Temperate grassland Desert

A porcupine is a rodent that solved the predator problem with about 30,000 spears. Its quills are stiffened hairs that lie flat until it is alarmed, detach at the lightest touch, and — in the American species — carry backward-facing barbs that make them nearly impossible to pull out and drive them steadily deeper once embedded. It cannot throw them, though people have believed that for two thousand years.

Overview

Porcupines are large herbivorous rodents in two only distantly related families — the Old World porcupines of Africa, Europe, and Asia, which are big, ground-dwelling burrowers, and the New World porcupines of the Americas, most of which climb trees. Old World species eat roots, bulbs, and fallen fruit; New World species eat bark, buds, and leaves, and gnaw bones for minerals.

The quills

Each quill is a keratin-stiffened hair, raised by skin muscles when the animal is threatened. They cannot be shot — they simply detach on contact, so a lunging predator impales itself. New World quills have microscopic barbs that make them easy to enter, very hard to remove, and prone to migrating inward about a millimetre an hour, so an embedded quill can reach an organ days later. The coating is mildly antibiotic, probably because tree-climbing porcupines often fall and stab themselves.

Warning first

A threatened porcupine turns its back, fans its quills, stamps, chatters its teeth, and releases a strong odour before it ever backs into an attacker or lashes its tail — a used quill takes months to regrow.

Status

Most of the ~30 species are Least Concern and stable, being adaptable and well defended. Some are hunted for meat and quills or killed as crop pests, and a few small-range species, like Brazil’s thin-spined porcupine, are threatened by habitat loss.

Porcupine: common questions

Can a porcupine shoot its quills?

No. This is one of the oldest and most persistent animal myths, going back to Roman times, but a porcupine has no mechanism to launch a quill through the air. What creates the illusion is that the quills are only lightly anchored in the skin and detach at the faintest touch. When a porcupine feels threatened it raises its quills and may rush backward or flick its tail toward the attacker, and any contact leaves quills stuck in the aggressor while the porcupine moves off. A dog that gets a face full of quills ran into them, or into a tail swipe. Loose quills can also fall out and fly a short distance when the animal shakes vigorously, which may add to the confusion.

What should you do if a dog or pet gets quilled?

Treat it as a veterinary matter, especially for more than a few quills or any near the eyes, mouth, or throat. The barbed tips make quills painful and difficult to remove cleanly, they can break off under the skin, and because they migrate inward with muscle movement they can travel to joints, the chest, or the abdomen over days and cause serious infection or injury. A vet will usually sedate the animal to remove every quill completely and check for fragments. If you must remove a quill in an emergency, grip it close to the skin with pliers and pull straight out without twisting, but do not cut quills, which does not deflate them and makes them harder to grasp.

What is the difference between a porcupine and a hedgehog?

They are not related and only look alike because both evolved spines. A porcupine is a large rodent, from about 1.5 kilograms up to 18 kilograms in the African crested porcupine, with long quills up to 30 centimetres and rodent incisors for gnawing wood and roots. A hedgehog is a small insect-eating mammal of the order Eulipotyphla, weighing under a kilogram, with short spines about 2 centimetres long that are never barbed, and its main defence is to roll into a tight ball, which a porcupine cannot do. Hedgehogs are an Old World group, while porcupines occur on most continents in two separate families.

Why do porcupines climb trees if they are so slow and heavy?

The New World porcupines are adapted for it, with strong curved claws, bare non-slip soles, and in some species a muscular prehensile tail that grips branches, and they climb to reach their main foods, bark, buds, and leaves, and to rest safely out of reach of ground predators. They are cautious, deliberate climbers rather than agile ones, and falls are common, which is thought to be why their quills evolved a mild antibiotic coating. The Old World porcupines took the opposite route, staying on the ground, growing larger, and digging extensive burrow systems, and they do not climb.

Sources & further reading

Written by HideShark Editorial Team · reviewed by HideShark Science Desk. Published September 10, 2026. Last updated September 10, 2026.

Quick facts

Scientific name: Hystricidae and Erethizontidae
Diet: Entirely plant matter, with the tree-dwelling New World porcupines eating bark, cambium, buds, leaves, and conifer needles, often stripping and killing branches in winter, and the ground-dwelling Old World porcupines eating roots, bulbs, tubers, fallen fruit, and crops, and gnawing shed bones and antlers for minerals
Thousands of modified hairs: A porcupine's quills are hairs stiffened with keratin, and a large individual carries around 30,000 of them over the back, sides, and tail, interspersed with softer guard hair and underfur, lying flat until the animal is alarmed and then raised by muscles in the skin
They cannot shoot their quills: The belief that a porcupine can launch its quills at an attacker is ancient and wrong, and what actually happens is that the loosely rooted quills detach on the slightest contact, so a lunging predator or a careless dog drives the quills into itself and the porcupine pulls away, leaving them behind
Barbed tips that migrate inward: New World porcupine quills have microscopic backward-pointing barbs near the tip that make them easy to enter and very hard to pull out, and body movement works an embedded quill deeper at up to about a millimetre an hour, so a quill can travel through tissue and reach an organ days later
A warning display before the quills: A threatened porcupine turns its back, raises and fans its quills, stamps its feet, chatters its teeth, and releases a pungent odour, and only if that fails does it back up rapidly or lash its spiny tail, since a used quill takes months to regrow
The quills are mildly antibiotic: The fatty coating on a North American porcupine's quills has antibacterial properties, which researchers think reduces the chance of infection when a porcupine inevitably falls from a tree and stabs itself with its own quills
Two families, not close relatives: The Old World porcupines of Africa, Asia, and southern Europe and the New World porcupines of the Americas both evolved quills but are only distantly related within the rodents, another case of the same defence appearing twice, and they differ in that Old World species are larger, terrestrial, and burrowing while most New World species climb trees
Range: Africa, southern Europe, the Middle East, and southern and Southeast Asia for the Old World porcupines, and from northern Canada and Alaska through the United States, Mexico, and Central America to northern Argentina for the New World porcupines, in habitats from tropical rainforest and temperate woodland to savanna, scrub, rocky hills, and desert, with tree-dwelling species tied to forest and ground species digging burrows or using caves and rock crevices.
Conservation status: Least Concern → ≈ Most of the roughly 30 porcupine species are common and assessed as Least Concern with stable populations, being adaptable, well defended, and able to live near people, though some are hunted heavily for meat and for quills and killed as crop and orchard pests, and a few species with small ranges, such as the thin-spined porcupine of Brazil's Atlantic forest and some Indonesian species, are threatened by habitat loss and hunting in the wild