Species: House mouse
Scientific name: Mus musculus
Claim to fame: Although there are no surveys to prove it, it’s a safe assumption that the house mouse is one of the most abundant mammals on the continent. There are mice native to North America, but the house mouse isn’t one of them. It likewise had numerous introductions as the country was being colonized (see below). This non-native rodent’s main claim to fame, however, is the variety of problems it causes for humans. In addition to destroying and contaminating food, their gnawing can damage woodwork, furniture, upholstery and clothing. They can also spread disease.
Species status: As far too many homeowners know, house mice are abundant in this area.
First discovered: The first scientific description of the house mouse was written by the famed naturalist Carl Linnaeus in 1758, but they were known to humans long before that. It’s thought house mice originated in Eurasia and were transported to other parts of the world as stowaways on ships and wagons. It’s presumed house mice had multiple introductions to North America throughout the 16th, 17th, 18th and 19th centuries; coming over on ships of explorers, colonists and merchants. From their initial establishment on the East Coast, the continent’s house mouse population went hand-in-hand with the advancement of settlement.
Family matters: House mice belong to the rodent family Muridae, a group of species commonly called Old World mice and rats.
Length: approximately five to eight inches
Diet: House mice are omnivores, which means they eat both meat and vegetative matter. The bulk of their diet consists of food remnants cast aside by humans, grains, seeds, fruits, insects and some types of plant matter.
Weight: up to one ounce
Distinguishing characteristics: House mice are grayish and have long, elongated snouts; small, black eyes that slightly protrudeing, large scantily haired ears and long, nearly hairless tails. House mice have excellent senses of smell, taste, touch and hearing. They have excellent running, climbing, jumping and swimming skills.
Life span: Twelve to 18 months in the wild and slightly longer in captivity
Habitat: In terms of habitat, this creature’s name says it all: For centuries house mice have flocked to people’s homes for shelter and food. In wild settings, house mice would probably reside in overgrown fields and forested areas, but it’s a moot point because that’s not where humans find them. We see them in barns, granaries, attics, garages, basements, outbuildings, woodpiles and other human-created areas where they can be snug, concealed and close to food.
Life cycle: Although house mice have many adaptive skills, the main reason for their success as a species is their reproductive abilities. House mice can breed year-round and can have up to 10 litters per year. Litters generally consist of from five to six offspring, but can be more. Mice reach sexual maturity at 5-7 weeks, which means females born early in the year can have several litters of their own before the year is finished. In nature, this type of reproductive ability is a compensation for being heavily preyed upon. Put this reproductive capacity in a setting where few of the animal’s natural predators (owls, hawks, snakes, etc.) exist and it creates problems. To get an idea of how bad things can get, in 1927 California health officials estimated the infestation level of one problem area of the state had reached 82,000 mice per square acre.