Rodents are a group of mammals defined by one key feature: one pair of continuously growing front teeth in both the upper and lower jaws. We have a lot of rodent species in Maine, including mice, rats, squirrels, beavers, porcupines, and more. Rodents are a fascinating and diverse family, but they’re not always the most popular animals. Many people view rodents, especially rats and mice, as pests, and sometimes use chemicals called rodenticides to control them.