Mice and rats are curious, intelligent creatures and, over time, have learned that where we live provides them with the things they need to live comfortably. Food, water, and safe, dry shelter are within the walls of our houses, and these opportunistic pests won't hesitate to take advantage.
When mice and rats move into our homes to nest, they don't fill out a renter's agreement; they are squatters and therefore do their best to stay out of our sight.
Rodents are prey animals and prefer to nest in quiet, out-of-the-way places. Basements, attics, crawl spaces, wall voids, and the backs of cabinets and appliances are common places to discover nests and rodent activity.