Hi! I've had my Syrian hamster for just over a year. He lives in a large, handmade cage that is glass fronted with a wire lid. He has multiple gnawing and boredom buster toys both on the ground and attached to the top of his cage, as well as fresh food and water and space to burrow and dig. Despite all of this, he seems to have recently staring gnawing on the wire on the lid of his cage. I've tried all kinds of stuff to prevent him from doing so, yet he persists. I'm after some advice as to why he is doing this/how to stop it??? Thanks!