Rodentia (Rodents)

Rodents are the most common mammals on Earth, with estimates that out of all mammal species, 40% are rodents.  

They can be found all over North America, living in various habitats and being kept as pets.  

There are many species of rodents.  These can live on the ground, underground, in the trees, or sometimes in water.

Rodents are mammals of the order Rodentia.  Rodent comes from Latin Rodere, “to gnaw.”

Rodents include common animals such as mice, rats, hamsters, gerbils, guinea pigs, and squirrels.

Most rodents have long tails, short legs, and sturdy bodies.  Rodents are primarily herbivorous, feeding on plants, leaves, stems, flowers, and roots.  Some are omnivorous.  

Rodents will defend themselves and use their incisors to gnaw on food.  Rodents have a pair of incisors on the lower and upper jaws.

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Rodents are social animals, who live in groups, and communicate.  Rodents can practice polygyny or monogamy but can also be promiscuous.      

Some rodents are classed as pests, spreading diseases and eating food stored by humans.  

Classification

There are several suborders, infraorders, superfamilies, and families of rodents.  Classification of rodents is difficult as traits similar to different families may not be due to common ancestry but parallel evolution.  

There are disagreements on how many suborders exist, with some scientists saying three and some saying two.

Brandt, a German naturalist in 1855, proposed dividing Rodentia into three suborders.  These are Sciuromorpha, Hysticomorrpha, and Myomorpha.  These suborders were based on the development of specific muscles in the jaw.

However, disagreements about this system have been raised, with suborders of two being proposed by Tullborg in 1899. The latest by Carleton and Musser in 2005 adopted a suborder system of five in their book, Mammal Species of the World.  These five are Anomaluromorpha, Castorimorpha, Hystricomorpha, Myomorpha, and Sciuromorpha.  There are 33 families, 481 genera, and 2277 species in these five suborders.  Not all of these species or families live in North America.

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Suborder – Anomaluromorpha

Family – Anomaluridae: Scaly-tailed squirrels (Not found in North America)

Family – Pedetidae: Springhares (Not found in North America)

Suborder – Castorimorpha

Superfamily – Castoroidea

Family – Castoridae – Beavers

Superfamily – Geomyoidea

Family – Geomyidae – Pocket gophers (true gophers)

Family – Heteromyidae – Kangaroo rats, kangaroo mice

Infraorder – Ctenodactylomorphi

Suborder – Hystricomorpha

Family – Ctenodactylidae – Gundis (Not found in North America)

Infraorder – Hystricognathi

Family – Hystricidae – Old World porcupines (Not found in North America)

Family – Bathyergidae – African mole rats (Not found in North America)

Family – Petromuridae – Dassie rat (Not found in North America)

Family – Thryonomyidae – Cane rats (Not found in North America)

Parvorder – Caviomorpha

Family – Heptaxodontidae – Giant hutias (Extinct)

Family – Abrocomidae – Chinchilla rats (Not found in North America)

Family – Capromyidae – Hutias

Family – Caviidae – Cavies, including Guinea pigs and the capybara (Not found in North America)

Family – Chinchillidae – Chinchillas, viscachas (Not found in North America)

Family – Dasyproctidae – Agoutis (Not found in North America)

Family – Cuniculidae – Pacas (Not found in North America)

Family – Dinomyidae: -Pacaranas (Not found in North America)

Family – Echimyidae – Spiny rats (Not found in North America)

Family – Erethizontidae – New World porcupines

Family – Myocastoridae – Coypu (nutria)

Family – Octodontidae – Octodonts (Not found in North America)

Family – Erethizontidae – New World porcupines

Infraorder – Incertae sedis

Family – Diatomyidae – Laotian rock rat (Not found in North America)

Suborder Myomorpha

Superfamily – Dipodoidea

Family – Dipodidae – Jerboas and jumping mice

Superfamily – Muroidea

Family – Calomyscidae – Mouse-like hamsters (Not found in North America)

Family – Cricetidae: Hamsters, New World rats, and mice, muskrats, voles, lemmings

Family – Muridae – True mice and rats, gerbils, spiny mice, crested rat

Family – Nesomyidae – Climbing mice, rock mice, white-tailed rat, Malagasy rats, and mice (Not found in North America)

Family – Platacanthomyidae – Spiny dormice (Not found in North America)

Family – Spalacidae – Mole rats, bamboo rats, zokors (Not found in North America)

Suborder Sciuromorpha

Family – Aplodontiidae – Mountain beaver

Family – Gliridae (also Myoxidae, Muscardinidae) – Dormice (Not found in North America)

Family – Sciuridae – Squirrels, including chipmunks, prairie dogs, marmots

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