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 1467
2 Bank Vole 1637
3 Beaver 1279
4 Blesmol 1113
5 Cane Rat 1325
6 Gambian Pouched Rat 1292
7 Gerbil 1184
8 Gray Squirrel 1480
9 Hamster Burrow 1280
10 Harvest Mouse Nest 1375
11 Hazel Dormouse 1291
12 Marmots 1114
13 Muskrat 1288
14 Pocket Gopher 1520
15 Prairie Dogs 1173
16 Tuco-tuco 1624
17 Wood Mouse 1354