The answer to 'why is my mouse trails' is that mouse trails are a common sign of a mouse infestation in your home. Mouse trails are the paths that mice create as they repeatedly travel back and forth, leaving behind grease, dirt, and droppings that create visible trails.
Mice are highly active and curious creatures, so they will often create well-worn paths as they search for food, water, and nesting sites. These trails are usually found along baseboards, behind furniture, or in other areas where mice frequently travel. Seeing mouse trails is an indication that you have an active mouse problem that needs to be addressed.