How Long Can Mice Live Inside a House?

The University of Michigan's Animal Diversity Web notes that in the wild, most house mice do not live beyond 12–18 months, worn down by predators, cold, and food scarcity. Protected mice — pets, lab animals, and mice living entirely indoors — average about two years and can occasionally live longer. Cornell IPM confirms house mice "can live outdoors if conditions are suitable, but can successfully live their entire life indoors," because a heated home removes the two biggest wild-mortality drivers: predation and cold.

A female house mouse can produce 5–10 litters a year of roughly 5–6 young each, and those offspring reach breeding age in just 5–7 weeks. That means a pair of mice that settle into a house in early fall can become a substantial population by mid-winter, all hidden in wall voids and attic insulation, well before any individual mouse's natural lifespan becomes relevant.

This is a distinct question from how long rats survive indoors, where water access is the bottleneck for an individual animal. For mice, the driver isn't one mouse's endurance — it's how fast a protected colony compounds through breeding. That's why "a mouse can't survive long without X" is the wrong frame for mice; the right frame is how quickly a small intrusion becomes more than one mouse.