Porcupine


Porcupines are large rodents with coats of sharp spines, or quills, that protect them against predators. The term covers two families of animals: the Old World porcupines in the family Hystricidae, and the New World porcupines in the family Erethizontidae. Both families display superficially similar coats of rigid or semi-rigid quills, which are modified hairs composed of keratin, and belong to the infraorder Hystricognathi within the diverse order Rodentia. The two groups are distinct and are not closely related to each other within Hystricognathi. The largest species of porcupine is the third-largest living rodent in the world, after the capybara and beaver.
The Old World porcupines live in Italy, West and South Asia, and most of Africa. They are large, terrestrial, and strictly nocturnal. New World porcupines are indigenous to North America and northern South America. They live in wooded areas and can climb trees, where some species spend their entire lives. They are generally smaller than their Old World counterparts and are less strictly nocturnal.
Most porcupines are about long, with a long tail. Weighing, they are rounded, large, and slow. Their colouration consists of various shades of brown, grey and white. Porcupines have various methods to defend themselves from predators, the most prominent being the use of their quills, which advertises their unsuitability for being preyed upon. This strategy is known as aposematism. To some degree, the spiny protection resembles that of the hedgehogs, echidnas, and tenrecs, none of which share any spiny ancestors; all of them, and also the old-world and new world porcupines, are products of convergent evolution. The spines of the various groups also vary markedly.
Humans have a varied history with porcupines, with some cultures considering a symbols of self-defense or cautiousness. Porcupines appear in mythology in regions where the animal has economic significance, such as for food or in the production of quillwork textiles.

Terminology and etymology

The word porcupine comes from the Latin porcus + spina, from Old Italian porcospino,. A regional American name for the animal is quill-pig.
A baby porcupine is known as a porcupette. When born, a porcupette's quills are soft hair; they harden within a few days, forming the sharp quills of adults.

Taxonomy and evolution

Classification

A porcupine is any of 29 species of rodents belonging to the families Erethizontidae or Hystricidae. The two families of porcupines are quite different, and although both belong to the Hystricognathi branch of the vast order Rodentia, they are not closely related.
Porcupines are distributed into two evolutionarily independent groups within the infraorder Hystricognathi, part of the suborder Hystricomorpha of the Rodentia:
Studies on the physical characteristics of New World porcupines initially described them as being the most basal group among the hystricognaths, and fossil records point to a common ancestor of Erethizontidae and all other hystricognaths occurring in the early Oligocene. Dorothée Huchon and Emmanuel Douzery wrote in 2001 on the diversification of the hystricognaths, reporting that molecular phylogenetic studies using nuclear genes suggested that the Hystricidae, Phiomorpha, and Caviomorpha lineages split some time 63 to 43 million years ago. This supported a single colonization event of South America by hystricognaths. A 2013 study of nuclear and mitochondrial genomes supports a mid-Eocene diversification of New World hystricognaths, with family-level splits occurring in the early Miocene.
Fossils belonging to the genus Hystrix date back to the late Miocene of Africa and Asia. One of the oldest known porcupine fossils is Hystrix primigenia, an Old World porcupine that lived in the late Miocene to the Pliocene; the oldest known porcupine fossil in Asia, Hystrix lufengensis, dates back, also in the late Miocene.

Biology

Old World compared with New World species

The 11 Old World porcupines tend to be fairly large and have spines grouped in clusters.
The two subfamilies of New World porcupines are mostly smaller, have their quills attached singly rather than grouped in clusters, and are excellent climbers, spending much of their time in trees. The New World porcupines evolved their spines independently and are more closely related to several other families of rodents than they are to the Old World porcupines.
The quills of New World porcupines are unique among spined rodents, being stiff with a circular cross section that is small in proportion to their length, which allows them to penetrate further into a potential predator before breaking off near the base. In contrast, the spines of Old World porcupines are similar to those of other rodents with spiny hair, such as the bristly mouse and short-tailed spiny rat, in that they have a concave cross-section and are shorter and softer, making them break off closer to the tip.

Description

Porcupines are rodents of varying fur color that are characterized by their abundance of protruding spines, or quills, found all along the head and body of the animal. Some species have quills that extend from the tail as well. They vary in size considerably: an adult Andean porcupine weighs roughly, while the crested porcupine can grow to weigh up to.

Longevity

Porcupines have a relatively high longevity and hold the record for being the longest-living rodent, with one individual named Cooper living over 32 years.

Diet

The North American porcupine is an herbivore and often climbs trees for food; it eats leaves, herbs, twigs, and green plants such as clover. In the winter, it may eat bark. The African porcupine is not a climber; instead, it forages on the ground. It is mostly nocturnal but will sometimes forage for food during the day, eating bark, roots, fruits, berries, and farm crops. Porcupines have become a pest in Kenya and are eaten as a delicacy.

Defense

Defensive behaviour displays in a porcupine depend on sight, scent, and sound. Often, these displays are shown when a porcupine becomes agitated or annoyed. There are four main displays seen in a porcupine: quill erection, teeth clattering, odour emission, and attack. A porcupine's colouring aids in part of its defence as most of the predators are nocturnal and colour-blind. A porcupine's markings are black and white. The dark body and coarse hair of the porcupine are dark brown/black and when quills are raised, present a white strip down its back mimicking the look of a skunk. This, along with the raising of the sharp quills, deters predators. Along with the raising of the quills, porcupines clatter their teeth to warn predators not to approach. The incisors vibrate against each other, the strike zone shifts back, and the cheek teeth clatter. This behaviour is often paired with body shivering, which is used to further display the dangerous quills. The rattling of quills is aided by the hollow quills at the back end of the porcupine. The use of odour is when the sight and sound have failed. An unpleasant scent is produced from the skin above the tail in times of stress and is often seen with a quill erection. If these processes fail, the porcupine will attack by running sideways or backwards into predators. A porcupine's tail can also be swung in the direction of the predator; if contact is made, the quills could be impaled into the predator causing injury or death.

Quills

Porcupines' quills, or spines, take on various forms depending on the species, but all are modified hairs coated with thick plates of keratin and are embedded in the skin musculature. Old World porcupines have quills embedded in clusters, whereas in New World porcupines, single quills are interspersed with bristles, underfur, and hair.
Quills are released by contact or may drop out when the porcupine shakes its body. New quills grow to replace lost ones. Despite what is commonly assumed and depicted in media, porcupines cannot launch their quills at range.
There are some possible antibiotic properties within the quills, specifically associated with the free fatty acids coating the quills. The antibiotic properties are believed to aid a porcupine that has suffered from self-injury.