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The common House mouse (Mus musculus L.) is what is called a commensal rodent.  Commensal is from Latin and means "to eat at the same table."  And this is exactly what mice do.  They live in close connection with humans, because humans provide them everything they need to survive, including food, shelter and warmth.  (Mice do not require water like most other pests and make their own water metabolically as they feed on grains, seeds and other foods.)  But mice do require food to live, shelter to hide, nest and harbor, and warmth, as they are small mammals and lose heat from their bodies in cold weather.

Mice may enter a facility through gaps and holes in masonry, under compromised (or lacking) door sweeps on doors, or they can enter with deliveries into the building, walk in at open loading docks, or be brought from an employee's home where there is a mouse issue.  Mice need only a ¼" opening to gain entry.

Once inside, your office can be very inviting to mice if there is a source of food and a warm place to hide nearby.  Once they are established in your office area, lab or workspace, they can be difficult to eliminate. They pee, poop, gnaw on and nest in items in and on your work space.  Yet, doing the following can help to eliminate the rodent population in your work area:

• Remove all food from your desk.  (Mice are attracted to candies, chocolates, chips, and other snacks you may have in your desk.)  If that is not possible, store all food items in sealed, air-tight containers constructed of heavy plastic, metal or glass.  Don't leave crumbs or dishes with food on them on your desk or in a sink out and overnight. Mice are nocturnal, meaning they forage for food mostly at night. However, if disturbed, or if there is a large population, you may also see them during the day.
• Make sure trash cans and recycle bins, especially the ones in your offices and kitchen break areas with any food trash items, are emptied at night and before weekends, especially before holiday long weekends.  Mice are naturally curious and have a good sense of smell and will be attracted to any food trash left for a long period of time.
•  If food trash cannot be removed by the end of the day or weekend, please tie it off in a plastic bag and place it in the hall or other designated place for pick-up in the morning.
• Regularly clean and sanitize your own desktop, underneath, around and behind your work area and any appliances (such as kitchen toasters, coffee makers, and microwaves) for dropped crumbs and other food items that mice could find attractive.
• Mice thrive in cluttered environments. Remove or store neatly away anything that you are not currently using.  Mice will shred papers, candy wrappers and tissues to make nests in desk drawers.  If you remove these items, this will help reduce the living and nesting space available to mice, and aid in the inspection and management/removal process of them.

 If you have done the above, and still notice new mouse droppings or other evidence on your desk or in your desk cabinets or shelves, please call our number below. Mouse droppings are small (about 1/8" to ¼" long, black and tapered at the ends and resemble a grain of rice.

Need Help?  Call 301-496-4294

Division of Occupational Health and Safety, ORS