The number of mice in a nest can vary, but typically a mouse nest houses between about 5 to 24 mice. Most commonly, nests contain around a dozen to two dozen mice, depending on factors like the age of the mice and whether other mice are nearby

. Some sources note that nests can have as few as one mouse or up to a family of 10, while others emphasize that 5 or more is typical

. Mice breed rapidly, with females producing 5 to 12 pups per litter and up to 10 litters per year. This prolific breeding means nests can quickly become crowded, especially since females and their pups often share nests, and multiple generations may cohabitate

. Male mice usually leave the nest around 20 days after birth to establish new nests, while females mature and remain to continue breeding cycles

. In summary:

• Typical mouse nest size: about 12 to 24 mice, often around a dozen

• Minimum observed nest size: around 5 mice, sometimes as few as 1

• Breeding: litters of 5-12 pups, up to 10 litters per year, leading to rapid population growth

• Nests are communal during breeding seasons, with females and their young living together

This explains why a single mouse sighting often indicates a larger infestation, as nests can quickly grow to contain many mice