It also helps keep unwanted wood, nut shells and soil from being eaten along with the food. Gnawing is not chewing. Gnawing means that the rodent nips off, or shaves off, layers of food or hard wood. When the food is inside its mouth, it chews the food into shreds, a paste, or pulp. It does this with flatter teeth called molars, before swallowing the food.
Some rodents have molars that grow all of the time much like the front teeth.
Still others have powerful jaw muscles that let them chew in a special circular way that shreds hard fibrous foods better. Most rodents, but not all, have four toes on the front feet and five toes on the back feet. Rodents, as a group, are very active and must eat much food. Some, such as the chipmunk, store foods and wake from a deep sleep to eat from time to time. Small members of the rodent family have more young in a season than any other mammals.