Hearing scratching or noises in the walls is one of the many signs of having rodents living in your walls. Keep in mind that the timing of the sounds could help you figure out what sort of critters you're dealing with or if it's just a tree limb rubbing against the house on a windy day or night
The grain weevil (also known as a wheat weevil) has nearly as long a lifespan. In short, the weevil larvae can destroy grains as they grow, mate, and lay their own eggs while safely inside a sealed bag of grains.