Roof Rats: Identification, Ecology, and Signs

Abstract

The roof rat (Rattus rattus), also known as the black rat, ship rat, or house rat, is an Old World rodent species originating in southeast Asia. Although it is not native to North America, it is established in most coastal and southern states in the continental United States (U.S.), Hawaii, and small populations exist in Alaska. In fact, roof rats are now well-established pests in many parts of the world. In 2001, roof rats were documented in Phoenix, and likely introduced into the area through freight, or shipment of food, livestock feed, or equipment. They have now settled into ideal habitat among old growth citrus trees, palm trees, and other mature landscaping, and take advantage of abundant irrigation canals and food resources around homes. Reports of roof rats and the areas they occupy in Arizona are ever increasing, most recently in Yuma, indicating that the roof rat is now well established, even in our harsh desert environment. Here in southern Arizona, it is not uncommon to experience consistent summer temperatures above 110 degrees F.