Rodents

Rodents and their fleas are capable of transmitting a variety of human diseases including plague, hantavirus, leptospirosis and salmonella.

Homeowners, business owners, or any group in Placer County can request a site visit to assess rodent issues. District services include rodent identification (rodent need not be present) and advice for prevention and control. Rodent inspections are scheduled based on technician availability. District employees do not bait or set traps, but provide valuable, detailed information, guidance and recommendations.

For more information on managing rodents, read Rodent Control for Homeowners.

These are most common rodents in Placer County:

Norway rat (Rattus norvegicus), sometimes called brown or sewer rats, are stocky burrowing rodents that are larger than roof rats. Their burrows are found along building foundations, beneath rubbish or woodpiles, and in moist areas in and around gardens and fields. Nests can be lined with shredded paper, cloth, or other fibrous material. When Norway rats invade buildings, they usually remain in the basement or ground floor. Norway rats live throughout the 48 contiguous United States. While generally found at lower elevations, this species can occur wherever people live.

Roof rat (Rattus rattus), sometimes called black rats, are slightly smaller than Norway rats. Unlike Norway rats, their tails are longer than their heads and bodies combined. Roof rats are agile climbers and usually live and nest above ground in shrubs, trees, and dense vegetation such as ivy. In buildings, they are most often found in enclosed or elevated spaces such as attics, walls, false ceilings, and cabinets. The roof rat has a more limited geographical range than the Norway rat, preferring ocean-influenced, warmer climates. In areas where the roof rat occurs, the Norway rat might also be present. If you are unsure of the species, look for rats at night with a bright flashlight, or trap a few.

For more information on rat control and prevention, please visit the UC Integrated Pest Management website.

House mouse (Mus musculus) House mice thrive under a variety of conditions; they are found in and around homes and commercial structures as well as in open fields and on agricultural land. House mice consume and contaminate food meant for humans, pets, livestock, or other animals. In addition, they cause considerable damage to structures and property, and they can transmit pathogens that cause diseases such as salmonellosis, a form of food poisoning. House mice are small rodents with relatively large ears and small, black eyes. They weigh about 1/2 ounce and usually are light brownish to gray. An adult is about 5 to 7 inches long, including the 3- to 4-inch tail.

For more information on the house mouse and other mouse pests, please visit the UC Integrated Pest Management website.