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• Deer Mouse

Peromyscus maniculatus

The deer mouse can be found in many areas of the United States, Mexico and Canada. In recent years the deer mouse has gained notoriety due to its association of Hantavirus. Hantavirus is a virus that deer mice excrete in their urine, saliva and droppings. Human exposure most commonly occurs by breathing contaminated dust after disturbing or cleaning rodent dropping or nests, or by living in an infested setting.

Coloring is often what makes the deer mouse distinguishable from the house mouse; pale gray to a deep reddish brown back and a white abdomen. Adult deer mice are always bi-colored including the tail. Another distinguishing sign is the deer mouse tail is covered with short hairs/fur. Hind feet have 6 pads each. Also, the eyes, ears, and body are slightly larger than the house mouse. Young are similar in appearance but are usually more grayer in color on the back. Adult deer mice are usually about 2.5 to 4 inches in length (measurement includes head and body) with a tail about 2.5 inches. Adults can weigh anywhere from 3/8 to 1.25 ounces. They are most often found in farming/rural areas and are rarely a problem in urban or residential areas unless the home borders a wooded area such as a park. Their runways are poorly defined and will often use runways of other small animals. Deer mice are considered nocturnal.

Like most rodents, deer mice are not picky eaters. Seeds, nuts, berries, insects, pet foods, and small animals such as centipedes are among favored foods.

Deer mice are reproductively mature by 5-6 weeks of age. Females usually have 3-5 young per liter with 2-4 litters per year. Gestation is 21-24 days. In the wild, the average life span is 2-24 months due to predators, however in captivity that can survive 5-8 years.

Outside, nesting areas can include tree hollows/cavities, log piles, abandoned bird/squirrel nests, animal burrows, and under decks. These are usually found at or below ground level. As temperatures drop, deer mice can enter a structure in search of shelter or food. They will also enter unused automobiles, RV's, or structures not often used by humans such as summer homes. Once inside a home they tend to nest in areas such as storage boxes, wall voids, in stuffed furniture, attics, basements, crawlspaces and tight places that offer protected shelter.

Important preventative measures include:

1. Removal of food sources.
2. Removal of waste piles, packing boxes, wood piles or anything that could be considered a "harborage site".
3. Securely seal cracks, gaps, and openings around doors, window frames, foundations, and siding - keeping in mind that any such areas 1/4 inch or larger is considered a point of access.

While there are many "self-treat" methods available such as traps and rodent bait or poisons, we strongly recommend no baits or poisons are used unless any interior infestation has been eliminated and access points repaired. Because baits and poisons are very fast acting, rodents may not be able to find an exit point before expiring which can lead to sever odor problems. We recommend these products be used only on the exterior of a home.

Because of the possible transfer of Hantavirus there are few very important things to remember when performing cleanup of an infested area. Always were gloves made of rubber, latex or vinyl and never stir up dust by vacuuming or sweeping. Any areas that could contain droppings or dust from droppings should be treated with a bleach water mixture prior to disturbing the area and allowed to soak for approximately 10 minutes. Any nesting material or expired rodents should be removed, double bagged and immediately disposed of appropriately. After removing gloves, always thoroughly wash your hands, preferably with a disinfecting soap.

If populations remain in excess then a call to Long Pest Control can develop an Integrated Pest Control program to eliminate the sightings and provide control of unwanted rodents year round.