All cotton rats have a strong connection with grass, which they feed upon, and in which they construct their runways. Within their range in southeast and central Arizona and western Mexico, Arizona cotton rats inhabit only grassy areas where there is enough water to support grasses, weeds, or brush. Learn more about the Sigmodon arizonae, more commonly known as an Arizona Cotton Rat, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.