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Rodentia
Order: Rodentia
Family: 30
Species: 1'702
The Rodentia represents over 40% of all placental mammal species, and over 38% of all placental mammal species. There are 3 Suborders within the Rodentia which are defined by jaw musculature:
Suborder: Sciuromorpha (Squirrel-like
rodents)
Families: 7
Species: 377
Suborder: Myomorpha (Mouse-like
rodents)
Families: 5
Species: 1'137
Suborder: Caviomorpha (Cavy-like
rodents)
Families: 18
Species: 188
The Sciuromorpha include rodents such as squirrels, beavers, chipmunks, prairie dogs and woodchucks. They inhabit a variety of environments from streams and forests to mountains and deserts. They live in a variety of homes that varies between species. Most squirrels for example live in a dry nest and twig nest in trees called a drey. Prairie dogs and chipmunks dig burrows and beavers build lodges out of mud and sticks in a pool or lake. Unlike other sciuromorphs, beavers have webbed feet that enable them to swim with extreme proficiency. The Sciuromorpha also include the flying squirrel which morphologically looks very similar to the flying lemur in that it has large folds of skin that stretch out between the limbs to allow gliding between branches.
Example species:
Eastern chipmunk
Tamias striatus
Length: 15.5-16.5 cm
Weight: 80-125 g
Social unit: Individual
Region: South-East Canada to Central and South-East USA
Status: Common
Black tailed prairie dog
Cynomys ludovicianus
Length: 28-30 cm
Weight: 0.7-1.5 kg
Social unit: Group
Region: South-West Canada to North Mexico
Status: Lower risk
Eastern grey squirrel
Sciurus carolinensis
Length: 23-28 cm
Weight: 300-700 kg
Social unit: Variable
Region: South and South-East Canada to South USA and Europe
Status: Common
The Myomorpha include the popular pets; rats, mice, gerbils and hamsters, plus voles, lemmings jerboa. The Myomorpha comprises over a quarter of all mammal species. They have elongated snouts giving them a pointed face, long whiskers and comparatively large ears. They are mostly nocturnal and are found world wide in almost all habitats. The only continent on which they are not found is Antarctica. Their diet consists of seeds, berried and nuts, habitat dependant. Most species live in nests, but the naked mole-rat for example lives in an underground burrow and voles occupy aquatic habitats. Species such as the jerboa have developed extremely long legs and very large ears in order to detect and escape from predators. This is because they tend to inhabit environments that comprise wide open spaces and are thus vulnerable to predation.
Example species:
Malagasy giant rat
Hypogeomys antimena
Length: 30-35 cm
Weight: 1-1.5 kg
Social unit: Group
Region: West Madagascar
Status: Endangered
The Caviomorpha are the most diverse order of Rodentia. They include the largest of all rodents; the capybara. Capybaras are semi-aquatic and as such have partially webbed feet. Their sensory organs are placed high on their head so that they can still see, hear and breathe whilst swimming. Caviomorpha also inhabit mountainous, forested, desert and stream habitats with arboreal, aquatic, and ground dwelling species such as the naked mole rat. Species also included in the Order are porcupines, chinchillas, guinea pigs and coypu for example. The Order generally encompasses all rodents that do not fit into the other two Orders, but the members are generally related by a relatively large head, a sturdy body, a short tail and slender legs.
Example species:
Capybara
Hydrochaerus hydrochaeris
Length: 1.1-1.3 m
Weight: 35-66 kg
Social unit: Variable
Region: North and East South America
Status: Common
Mara
Dolichotis patagonum
Length: 43-78 cm
Weight: 2 kg
Social unit: Pair
Region: South South America
Status: Lower risk
Author: Emma-Louise Nicholls
Last updated: 20th November 2005
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