House mouse

Mice eat seeds, roots, leaves and stems.

They eat bugs too. Indoors, they nibble almost any food they can find, so people keep food in closed boxes.

In the wild, house mice eat many kinds of plants: seeds, juicy roots, leaves and stems. When they can, they also eat insects such as beetle larvae, caterpillars and cockroaches.

In buildings, mice will eat almost any food people leave out, and even nibble glue and soap. Many mice store food, and some live right inside places where people keep food. That is why people keep food in sealed containers.

ADW describes a broad omnivorous diet: in the wild, seeds, fleshy roots, leaves and stems, plus insects such as beetle larvae, caterpillars and cockroaches, and carrion when available. In human habitation, house mice eat any accessible food and household materials such as glue and soap. Many store food or live inside food stores.

The diet has consequences for people and wildlife. Mice eat and contaminate stored food with their droppings and are agricultural pests in some areas. Where they are abundant they can consume large quantities of grain, making it unavailable to other, perhaps native, animals. In turn, they are important prey for many small predators.

Mice are mostly awake at night.

They live in family groups. They squeak to each other in the nest and leave smells as messages.

House mice are mostly active at night, though some living in buildings come out by day. In the wild they nest in cracks in walls and rocks or dig burrows with several rooms and three or four exits. Indoors they build nests of shredded paper or cloth in hidden spots near food.

A strong male usually guards a territory with several females and their young. Mice squeak to each other in the nest and use smells to share messages.

Mostly nocturnal, house mice may be active by day in buildings. Wild mice nest in rock or wall crevices or dig burrows with complex tunnels, nesting and storage chambers and three or four exits; commensal mice nest behind rafters, in woodpiles or in storage areas, lining nests with shredded material (ADW).

Living with people, they are both territorial and colonial: a dominant male holds a territory with a family group of several females and their young, and the group defends it against outsiders, while aggression within the group is rare. Females form a loose hierarchy. Mice squeak in the nest and use pheromones to signal dominance, family membership and readiness to breed. Predators include cats, foxes, weasels, mongooses, snakes, large lizards, hawks, falcons and owls.

There are lots and lots of house mice.

Wild mice can carry germs that make people sick. So we watch them, but we do not touch them. People take care with pet mice too.

House mice are not in danger. The IUCN lists them as Least Concern because they are widespread, common and good at living in buildings.

Mice and people have a mixed relationship. Mice can spoil stored food, and wild mice can carry germs that make people sick, such as a virus called LCMV, so health experts advise not handling wild mice or their nests and droppings. Tame lab mice, though, have helped scientists learn a great deal about medicine and genes.

The IUCN lists Mus musculus as Least Concern (2016 assessment, amended 2021) with a stable population: it is widespread, abundant and thrives in human-made habitats, faces no major threats and needs no conservation measures. It is commonly regarded as a pest.

ADW notes that house mice eat and contaminate stored food, damage woodwork, furniture and fabric, and contribute to the spread of several diseases. The CDC identifies the common house mouse as the source of lymphocytic choriomeningitis virus (LCMV), spread through fresh urine, droppings, saliva or nesting material, and advises avoiding contact with wild mice and taking care with pet rodents. Domesticated and albino strains are commonly used as laboratory animals, especially in medicine and genetics (ADW).