I am sure that someone has mentioned that rodents have to keep gnawing all the time to wear down there teeth as they just keep growing. At our place the wood of the house and rubber hoses in the car are the favorite choice. We had one chew through a gasoline hose once so after that we keep the car in the barn where only the mice can chew on it. Sigh... And there are definitely places where the wood on the outside of the house is sadly worn and clearly chewed down a layer though not yet, thanks the Gods, all the way through.