There are several species of chipmunks that all look exceedingly similar to each other. They are also often confused with ground squirrels, with the big differences being that they are much smaller and have stripes across their eyes.
Chipmunks only weigh 2 to 3 ounces. They have expandible cheek pouches for carrying food and often live in underground burrows (although they are excellent climbers as well). Where they are used to people, they are often very bold and are constantly getting into trouble... and backpacks.
The word 'chipmunk' comes from 'chitmunk', the Algonquin (a Native American tribe from the East coast and Canada) word for the animal.






The typical stuffed cheeks.

Here one can clearly see the difference between a ground squirrel (left) and a chipmunk (right).