Light brown or light gray, the House Mouse is small and slender with large ears and small eyes. They have a keen sense of hearing, taste, smell and touch. While they are mostly active at night, they can be spotted during the day searching for food. Although they usually feed on cereal grains, they will eat almost anything. They nest within structures or burrows and establish a territory near food sources, generally 10 to 30 feet from their nest. The House Mouse is a prolific breeder.