PORCUPINES: A PRICKLY SUBJECT

The name “porcupine” means “quill pig” in Latin, but the porcupine is a rodent, not a pig. Porcupines are mammals that are most closely related to beavers, caviomorphs, capybaras, and other rodents. Porcupines have soft hair mixed with very sharp, stiff quills [= modified hairs] embedded in their skin musculature. There are no quills on their belly, face, or feet.

A group of porcupines is called a “prickle” (I am not kidding!).

In the “Old World” today, there are seven genera and 30 species of porcupines (all in family Hystricidae). They live in Africa, Europe, and Asia (including Sumatra and Malaysia). “Old World” porcupines have no microscopic bards on the ends of their quills.

An example of an “Old World” porcupine, i.e., a Hystricidae porcupine. It lives in forests, is an omnivore (eats plants and carrion), and does not climb trees.

In the “New World” today, there are four genera and 12 species of porcupines (all in family Erethizontidae). They live in northern Argentina to Ecuador, Brazil, southern Mexico, and North America (as far north as Alaska and northern Canada). “New World” porcupines have quills possessing microscopic bards, which are pointed shafts that overlap one another. The bards help prevent the quills from being pulled out of the predatory animal they are in.

An example of a “New World” porcupine: Erethizone dorsatum, a herbivore that inhabits forests, shrublands, and grasslands in the region from Mexico to Canada and Alaska. This species is 8 to 40 pounds in size, has black to brown fur and long claws, and is nocturnal. It does not hibernate. It can climb trees.

A porcupine quill, length 3.7 inches (83.5 mm). Locality unknown. 

Porcupines are characterized by their very sharp-tipped quills (as shown above).  Contrary to popular opinion, porcupine quills cannot be “shot” into the animal that is bothering them, but the quills do easily detach from the porcupine when a predator attempts to bite it. The quills have various shapes depending on their location on the animal. A single porcupine can have up to 30,000 quills. Porcupine quills are solid at the tip and the base but hollow for most of the shaft, thereby allowing the animal to float in water, if necessary. The quill material is keratin, a substance also found in human hair and fingernails. 

The quills protect the rather shy porcupines from their many predators, which include dogs, foxes, wolves, coyotes, bobcats, lynxes, mountain lions, lions, weasels, bears, eagles, owls, dogs, and humans, etc. 

If a porcupine loses a quill, it grows a new one. Their quills have natural antibodies that prevent infection if a porcupine get stucks by its own quills. 

Porcupine quills have long been used by indigenous people in making artwork and decorative clothing. Today, one can buy small bags of porcupine quills online for use in hobbies, etc.

The early evolutionary history of porcupines is not well established. The reasons are because of the pacucity of remains of their immediate ancestors, as well as the paucity of early porcupine fossils. Additionally, porcupines are morphologically closely transitional with other early Cenozoic rodents (e.g., rats and caviomorph rodents); thereby causing considerable uncertainty for paleontologists.

According to Sheng et al. (2020), who used DNA studies, the earliest porcupine fossils are late Miocene in age in both China and Europe.  

There are very sketchy reports that New World porcupines “appeared” as early as Oligocene age in age South America. It remains a perplexing mystery as to how porcupines “came to be” in South America. Some researchers believe that they floated on vegetation rafts from Africa, but there is no scientific proof of this hypothesis, which has been used to is explain how primates from Africa arrived in South America (see my previous post on primates). For those of you who are interested in reading more about this "floatation hypothesis," I highly recommend reading an online article (Bechly, 2018), which has an excellent review of this topic, as well as an extensive literature list with links.   

Procupines were present in South America at least somewhat prior to Pliocene time in South America. They are known to have migrated during late Pliocene time from South America into North America (i.e., during the Great American Biotic Exchange = GABI; [see my November 1, 2022, blog post entitled "A Compilation by R. Squires

of Cenozoic Land Bridges" concerning this migration event]).

Prehensile-tailed porcupines are native today in South America: Venzuela, Guiana, Brazil, Bolivia, Paraguay, northernmost Argentina and also on the island of Trinidad. These porcupines, which are notcurnal, use their tail to "hang out in trees." (national zoo.si.edu)

REFERENCES CONSULTED:

The Animal Diversity Web (online) at https://animaldiversity.org

Animals.sandiegozoo.org/animals/porcupine

Bechly, G. 2018. Hypothesis that some animals were carried over the            Atlantic Ocean on rafts of vegetation. evolution news.org/2018/06rafting-stormy-waters-when-biogeography-contradicts-common-ancestry/

Prehensile porcupines: https:/nationalzoo.si.edu

Sheng, G. and 7 others. 2020. Ancient DNA of northern China Hystricidae sub-fossils reveals the evolutionary history of old world porcupines in the late Pleistocene. BMC Evolutionary Biology 20, no. 88. (a free pdf)