Reference Article

from Wikipedia, the free encyclopedia


Rodentia is an order of mammals also known as rodents, characterised by two continuously-growing incisors in the upper and lower jaws which must be kept short by gnawing.

Forty-percent of mammal species are rodents, and they are found in vast numbers on all continents other than Antarctica.

Common rodents include mice, rats, squirrels, chipmunks, gophers, porcupines, beavers, hamsters, gerbils, and guinea pigs.

Rodents have sharp incisors that they use to gnaw wood, break into food, and bite predators.

Most eat seeds or plants, though some have more varied diets.

They have historically been pests, eating human seed stores and spreading disease.

Rodents evolved some time around the end of the Cretaceous period c 65 million years ago.

In terms of number of species — although not necessarily in terms of number of organisms (population) or biomass — rodents make up the largest order of mammals, with over 40 percent of mammalian species belonging to the order.[1] Their success is probably due to their small size, short breeding cycle, and ability to gnaw and eat a wide variety of foods.(Lambert, 2000) There are about 2,277 species of rodents, about 42% of all mammal species.

Rodents are found in vast numbers on all continents except Antarctica, most islands, and in all habitats except for oceans.

They are the only placental order other than bats (Chiroptera) and sea lions (Otariidae) to reach Australia without human introduction.

Note: This article excerpts material from the Wikipedia article "Rodent", which is released under the GNU Free Documentation License.

See the following related content on ScienceDaily:

Related Stories

Share This

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:
from the past week

In Other News

... from

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins