Porcupines are separated between two families: Hystricidae, or old world porcupines, and Erethizontidae, or new world porcupines. In the two families, seven genera groups exist and 23 different living species of porcupine are listed. A small subfamily exists in Erethizontidae known as Chaetomyinae, which contains one other species of porcupine. The common factor linking all porcupine species is the presence of some form of spine used for protection from predators.
Brush-tailed porcupines are old world species that look like long ratlike animals. The African and Asiatic brush-tails are the two species in this group. Both grow to around 2 feet in length and have spines all over their backs. The species are known as brush-tails because of the brush of smaller spines at the tip of their tails.
Crested porcupines are old world types, so called because of patches of spines on their necks which they can raise in defense. Across Asia and Africa, eight species of crested porcupine exist, all of which are large and bulky, slow-moving animals. Spine length varies by species with some having short, almost hairlike bristles and others having long sharp spines. Species in this group include the Cape, North African, Sudan and Sumatran porcupines.
The long-tailed porcupine is in its own genus and is the smallest of the old world porcupines. Like the brush-tailed genus, they look like spiny rats. They grow to around 19 inches in length and have long, bare tails except for a spiny-haired tip. The species can break off its tail as a predator defense, but once lost it will not regrow.
The bristle-spined rat is a new world species native to Brazil. It has the body shape of a large rat with thin spines along its back and a hairless tail. Unlike old world porcupines, this species is an adept climber moving more quickly in the trees than on the ground.
In South America, four species of new world porcupines known as prehensile-tailed porcupines are found. They are stout-bodied animals with thick, short spines. The species in this group are adapted for a lifestyle in the trees with strong clawed feet for climbing and agile tails which can wrap around branches for stability. The black dwarf, Brazilian, Rothschild and bicolor-spined porcupines are in this group.
The stump-tailed porcupine is the only species in its genus in the new world family. It is a small species which, as its name suggests, has a short tail. Even so, it is a good climber and spends much of its time in trees.
North American Porcupine
The North American porcupine is the largest and most northern ranging of the new world porcupines. It lives in most of North America and areas of northern Mexico. It is North America's second largest rodent and has a stout body and long, barbed spines.
The final genus in the new world porcupine family are the hairy porcupines, of which there are nine different species. All species are medium to small in size with both thick hair and sharper quills on their backs. Tails are completely bare and used to help the porcupines climb. Species in this group include the frosted hairy dwarf, brown hairy dwarf, and the Mexican hairy porcupines.