When fall and autumn set in, the mouse may have another litter of babies as they did in the spring. They may also begin preparing for winter and seek out shelter and warmth. Many times they will find this in barns, sheds, or even your home. During this time you may hear gnawing, because if they don't their teeth can over grow. Because of their physical capabilities they are able to gain entry into sstructures by gnawing, climbing, jumping and swimming. Mice constantly explore and learn about their environment. They are great about memorizing locations and pathways, obsticles and food, water and shelther, and other elements in their domain.