A mouse's eyesight is not very good. It mainly relies on smell and feel, via its whiskers and paws, to navigate. It has a keen sense of smell and hearing and very sensitive whiskers. By scurrying around, sniffing and letting its whiskers drag on the floor or ground, a mouse can smell and feel little crumbs, scraps and other pieces of food laying around.
Smell and Feel
Mice are territorial. They make a nest, then establish a certain territory around the nest. They will follow routines of checking around the perimeter of their territory, both to identify any predators (or other mice) and to locate food. Once they use their senses to locate the best food sources within their territory, they will regularly revisit them.
Mice communicate with each other via body language, high-pitched noises (some inaudible to humans), and, some speculate, via their whiskers. Mice often communicate with each other about dangers as well as food sources.