These mammals are called rodents. Rodents are a diverse order comprising about 2,277 species, including rats, mice, squirrels, and beavers. They are characterized by sharp chisel-shaped incisors and strong hind legs, which enable them to gnaw nuts, seeds, leaves, and stems. Rodents are found in all habitats except polar ice caps and are the most successful and diverse mammalian order due to adaptability.