The roof rat's scientific name is Rattus rattus. Historically, they were associated with having spread the plague or black death during the Middle Ages. The roof rat is also known as the black rat, even though it is not necessarily black in color, but rather is usually dark brown. The typical roof rat measures between 13 to 18 inches long, including its tail and is sleek, slender, and agile. The roof rat is distinguished from other rats by that tail, which is longer than the rest of its body.
Roof Rats in the Phoenix Area
Roof rats are not unique to the state; they are partial to warmer climates. The roof rat can be found along the southern Atlantic and Gulf coastal states from Virginia to Texas and throughout Florida. They also are located along the Pacific Coast of California, Washington state, and Oregon.
The first rat outbreak occurred in the Phoenix area in 2001 when they appeared in the Arcadia neighborhood in east Phoenix. In 2004, there were confirmed roof rat sightings in Phoenix, Tempe, Glendale, Paradise Valley, and Glendale. The source of the infestations is unknown, but many suspect migration may have occurred in cars, trucks, and by movement of plants and trash.
What to Know About Roof Rats
While roof rats share many characteristics with the rest of the species, they also have some unique attributes:
- Roof rat droppings are long and cylindrical.
- Roof rats are nocturnal.
- Roof rats can transmit diseases like the bubonic plague and typhus.
- Roof rats will enter homes and buildings. They only need a hole the size of a quarter to gain entry.
- Roof rats are excellent climbers. They can climb walls and use utility lines and fences to travel from structure to structure.
- Outside, roof rats will nest in trees, woodpiles, garbage, and plants. In Arizona, oleanders seem to be a popular nesting location.
- Inside, high places, like attics, are their preference.
- Roof rats do not burrow in the ground or swim.
- Roof rats eat fruits, vegetables, nuts, pet food and invertebrates like spiders and worms. They will also eat paper.
- Female roof rats can each have up to four litters a year, each containing five to eight young. In urban areas where they have no natural predators, the survival rate of the babies is high.
- The following items around the home may be more prone to attracting roof rats: palm trees, yucca plants, pampas grass, honeysuckle, Italian cypress trees, any heavy shrubbery, wood piles, and storage boxes.
How to Tell If You Have Roof Rats
If you have citrus trees and notice hollowed-out fruit on the ground or in the trees, this is an indicator that roof rats are present. Hearing gnawing or scratching sounds in the attic or the walls, are another indicator. Pay attention to any droppings in attics and storage areas. If you notice oily rub marks on the house or small holes in the screens, the roof rat may have moved in.
How to Prevent Roof Rats From Moving In
Preventative measures are the best defense against roof rats.
- Repair any broken or torn screens.
- Keep trees trimmed, and bushes and vines thinned. Make sure trees are pruned back from the house at least 4 feet.
- Keep lids on garbage cans.
- Clean up debris in the yard and storage areas.
- Seal around the attic.
- Don't leave pet food outside, especially at night.
- Pick your citrus as soon as it is ripe. Remove any fallen citrus from the ground.
- Store wood at least 18 inches above the ground and 12 inches away from the walls.
- Eliminate standing water and fix leaky faucets.
How to Get Rid of Roof Rats
Trapping roof rats is a preferred method of control, especially if residents have small children or pets that might be affected by poisons. Snap traps are widely available. Several city offices offer traps at very reasonable prices for residents, as part of their education and prevention program. Check the website of the city/town in which you live for more information about traps and their availability.