In appearance, the roof rat is somewhat similar to the Norway rat and to the native pack rats and cotton rats. Probably the most easily recognized characteristic that differentiates the roof rat from native rats is its tail. Roof rats' tails are hairless, scaly, and longer than the combined length of their head and body.
Roof rats' head and body are usually 7-8 inches long. Ears are large and nearly naked. The snout is pointed. Roof rat droppings are black, banana-shaped, and are about ¼ - ½ inch long.
Roof rats are omnivores (plant and animal eating). They are very fond of fruit, especially oranges. In addition to fruit, they will feed on fruit producing ornamentals, dates, stored food, and birdseed in feeders, insects, snails and garbage. These rats will also feed on stored feed and livestock feed and will contaminate much more then they actually eat. They obtain much of their water requirement from their food, but unless their diet includes a sufficient amount of succulent plant material, they will require a source of free water such as landscape irrigation.
Roof rats generally begin searching for food shortly after sunset. These rats may cache or hoard considerable amounts of solid food, which they will eat later. These food caches may be located in attics, in dense vegetation such as hedges, or in a variety of other hiding places near their nests.
Effective methods of roof rat control include exclusion, habitat modification, trapping, and poison bait. Two control methods NOT recommended are chemical repellents and electronic devices. No chemical repellents are registered for rat control. There is no sound evidence that products sold as general animal repellents are effective in repelling rats.