SquirrelRodents are placental mammals that have four teeth, known as incisors, which grow constantly.

Every rodent has two incisors in its upper jaw and two its lower jaw. Rodents must continuously gnaw at things to keep their teeth from growing too large.

There are over 2000 species of rodent. There are more rodent species than species of any other type of mammal. Rodents make up 40% of all mammal species.

Rodents can be found on every continent except Antarctica.

CapybarasWhile many rodents are small, the capybara, the largest living rodent on Earth, can weigh more than 100 pounds.

African pygmy mouseThe African pygmy mouse and the pygmy jerboa, two of the world's smallest rodents, weigh less than half an ounce.

You can find out more about different kinds of rodents by clicking on the links below.

1 African Ground Squirrel 1456
2 Bank Vole 1633
3 Beaver 1275
4 Blesmol 1108
5 Cane Rat 1323
6 Gambian Pouched Rat 1288
7 Gerbil 1181
8 Gray Squirrel 1478
9 Hamster Burrow 1278
10 Harvest Mouse Nest 1372
11 Hazel Dormouse 1288
12 Marmots 1111
13 Muskrat 1285
14 Pocket Gopher 1517
15 Prairie Dogs 1170
16 Tuco-tuco 1621
17 Wood Mouse 1349