Mice and Rats
Mouse on museum stagecoach (C. Sullivan, NPS)
Although there are other types of rodents that can wreak havoc on buildings and grounds, mice and rats are the primary rodents that consistently seek harborage inside buildings and storage spaces.
Where can I find general guidance on IPM for rodent control?
- Corrigan, Robert M. Rodent control: a practical guide for pest management professionals. 2001.
What do I need to know to protect my health and safety when handling mouse- or rat-infested materials?
- NPS Conserve O gram 2/8, Hantavirus Disease Health And Safety Update, National Park Service
- Cleaning Up After Rodents, Centers for Disease Control and Prevention
The three most common species of pest rodents are the Norway rat (Rattus norvegicus), the roof rat (Rattus rattus), and the house mouse (Mus musculus), all of which were introduced to North America. There are also native rodent species, though they are less often associated with damage and typically avoid humans. Deer mice and white-footed mice (Peromyscus sp.), as well as meadow mice (Microtus sp.) are exceptions, and may live around or in buildings. Visit the NPS manual on Commensal Rodents for more details.
- Norway rats are also known as wharf rats, sewer rats, or brown rats. Adults range in size from 12-18 inches (30-46 cm) from nose to tip of tail, and weigh 12-16 ounces (200-500 grams). It has a blunt nose, small hairy ears, and its body is longer than its tail. They are found throughout the United States.
- Roof rats are also called black rats or ship rats. They are not as stocky as Norway rats, weighing 5-9 ounces (150-250 grams), and measuring 13-18 inches (33-46 cm) from nose to tip of tail. It has a pointed nose, larger hairless ears, and its tail is longer than its body. They are found mostly in coastal areas.
- House mice weigh from ½ to 1 ounce, and vary in color from light brown to dark gray. They have moderately large ears and nearly hairless tails that are roughly the same length as their body. They are found nearly everywhere that there are humans.
- Deer mice and white footed mice sometimes become pests when they enter buildings adjacent to woodland or fields. They are similar in size to house mice, with white feet and undersides, and brownish upper surfaces.
- Meadow mice or voles (Microtus sp.) sometimes become a pest in structures. Unlike house mice, they are less agile, with larger, bulky bodies, shorter tails and small ears and eyes.
Signs of Infestation
How do I know if I have a mouse or rat infestation?
- NPS Conserve O gram 3/12, Identifying Mouse and Rat Damage in Museum Collections, National Park Service
Control and Treatment
How do I pest-proof my facility to prevent a mouse or rat infestation?
- Illustrated Guide to House Mouse Exclusion and Monitoring, Museum Pests Working Group
- NPS Rodent Exclusion Manual, National Park Service, Mechanical Rodent-Proofing Techniques, National Park Service
- Pest Proofing Tips for Building Owners, Managers and Staff, NYC Health – NYC.gov
Where can I find guidance about rodent exclusion for new construction?
- NebGuide G1530, Rodent-Proof Construction – Structural, University of Nebraska, Lincoln Extension – Institute of Agriculture and Natural Resources
- NebGuide G2017, Rodent-Proof Construction – Drains and Feeding Equipment, University of Nebraska, Lincoln Extension – Institute of Agriculture and Natural Resources
How do I set up a trapping program to monitor for mice and rats?
- Rodent Trapping Tip Sheet, Museum Pests Working Group
- Trap Placement Diagram for mouse snap traps, Museum Pests Working Group
- NPS Museum Handbook, Part I, Museum Collections. Chapter 5: Biological Infestations, National Park Service
- Visit the Monitoring — Trapping for Rodents section of this site for more information.
Mice and rats feed on a wide variety of foods.
- Norway rats prefer protein-based foods such as meat, fish, insects, pet food, nuts, and grain. They will readily feed on human garbage.
- Roof rats prefer plant foods such as fruits, nuts, seeds, berries, vegetables, and tree bark. They will occasionally feed on human garbage.
- Mice feed on cereals, as well as foods high in fat and protein (butter, nuts, meats, etc.), as well as sweets, including chocolate.
Created 2017, Updated 2022