Squirrels, such as the Eastern Gray Squirrel, Sciurus carolinensis, at the right, as well as chipmunks, are rodents, just like mice and rats. They all belong to the order Rodentia. A conspicuous feature uniting squirrels with rats and mice is their teeth. In the front of all rodent mouths, including those of squirrels, there are four chisel-like gnawing-teeth called incisors, two above and two below. Immediately behind the incisors there's a space, and then flattish back teeth appear. These back teeth, or "cheek" teeth, are adapted for grinding. The vast majority of rodents also have four toes on each front foot, and five on each hind foot.