They are great for stimulating your cats natural instincts, senses and mind so that you have a more contented pet. They keep them occupied and active as they try to retrieve their prize from the ball. These balls are specially designed as a fun healthy way to exercise your cat and get them to utilise any excess energy which may cause them to misbehave. Put some of your pet's favorite snack inside and the cat will be attracted. It's like a duck quacking when the ball is in movement, very funny.