We got this mechanical mouse for our new cat, and he likes it fine, but, to our surprise, our 8-year-old dog, who never plays with dog toys, suddenly started playing with this thing. He will growl at it, bark at it, grab its tail in his teeth and drag it around. He's like a puppy again. It is really fun to see him go after this mouse. The mouse goes backwards and forwards, turns, backs up, goes forward again, all in such random motions that it makes the dog think it's a real threat, and it's his job to be a hero and stop it from moving. It's held up nicely and seems to take forever to run out of power. This is a real winner of a pet toy.