They are different, and yet in a way they same. Neither one wants to back down. They both are stubborn, I think. The cat is older though, you're right, and perhaps schemes a bit more. The dog seems to be acting on impulse. To him it's a game.
I think chewing will stop in time. We are mostly concerned with his health. If he eats the wrong thing he can get sick.
Thanks very much for stopping by and offering your delightful comment.