This fall it is time for me to resume my reluctant pastime trapping North America's most abundant fur bearer: the mouse.
Daily, I become the heartless trapper patrolling trap lines from my basement, under the kitchen sink, and to the laundry disposing of my quarry. When observed up close, mice are cute; they have big black eyes, white feet and under parts, a gray rusty back, and a long bicolored tail, dark on top and white below. No wonder Mickey and Minnie Mouse caricatures captured people's affection in the early days of movies.
In a natural setting outdoors, mice can be an enjoyable sight. I still smile relating the story about disappearing trail mix while my wife and I slept on the ground in an Adirondack lean-to 30 years ago. In the morning after inspecting our knapsacks, we discovered only M&M's and mouse feces in the bag previously containing raisins and peanuts.
In midwestern and northeastern United States, two nearly identical mice species, the white-footed mouse and the deer mouse predominate. Distinguishing the two apart often requires an expert. The white-footed mouse has a tail slightly shorter than the body, while the deer mouse measurements are just the opposite. The tail on one of my dead mice measures 9.5 cm and the body 8.2 cm, suggesting it is a white-footed mouse.
While I realize mice in my house eat very little, their presence can be startling as they scurry across the floor. The most important reason to keep mice out of the house is to avoid spreading serious disease to humans. Mice can transmit the Lyme disease bacteria, the infamous plague, and the Hantavirus responsible for pulmonary infection more common in the American southwest but also reported in Florida and New York. The most effective way to eliminate mice is to kill them with various snap traps.
Homing is a remarkable talent of mice. Jeff Tome, a senior naturalist at the Jamestown Audubon Society, related an experiment he conducted 15 years ago. Live captured local mice were transported a half-mile down the road where they were released after painting their tails with nail polish. Several days later the same mice were recaptured alive at the Audubon building having avoided numerous natural predators such as owls, hawks and foxes on their return. If one prefers to live-catch mice they should be released far away so they become lost returning home.
The white-footed mouse and the deer mouse are abundant because they are prolific breeders. An average of four to five babies are born after gestation of only 23 days. The babies, born naked, with eyes and ears closed, mature quickly. By six weeks of age, the babies are ready to breed. A female may have two to four litters each year depending on the weather and availability of food. At times when a mother leaves her nest to feed another mother may enter the nest, killing the babies, which is infanticide. Mice abundance is also kept in check since mice are a most important prey species.
Both mice live in fields and woods, but the deer mouse even tolerates the desert. The deer mouse hibernates, therefore storing little food, unlike the white-footed mouse which caches food to eat during the winter. Most mice are omnivores feeding on plants such as seeds, nuts, and grasses and meat like insects, caterpillars, and small birds.
Biological researchers use mice for genetic experiments due to their gentle nature, ease of care, frequent breeding, numerous offspring, and rapid maturation. Just this week, the Wall Street Journal and The Post-Journal featured a report of Japanese scientists who added growth factors to mouse skin reprogramming the cells so they could be coaxed to become eggs or sperm. The eggs were fertilized in a test tube then implanted in a mouse uterus developing healthy, fertile mice. Whether this could be applied to humans is just speculation now.
The delightful white-footed mouse is industrious, a prolific breeder, and a useful medical research tool, but is a carrier of human disease and therefore an unwelcome guest in my home.