How does the diet of an outdoor house mouse differ from the diet of an indoor house mouse?

The diet of the house mouse (Mus musculus) varies significantly based on its environment:

• Outdoor house mice: These populations primarily consume seeds—including grains—and insects.12
• Indoor house mice: These mice are essentially omnivorous and will eat nearly anything that is digestible.2

Because indoor house mice are opportunistic feeders, they are frequently considered pests in human dwellings, where they can contaminate food supplies and cause property damage.1