Mol and Zi are quite lazy, and spend loads of time asleep - Mol is possibly slightly more active, although she doesn't have to get off the bed to eat her wet food, only to drink, have biscuits and toilet. Since I got Seraquin and gave some to Zi though, she has been more playful, and just getting that look in her eye and dashing round the bed - just moved the toy, Zi batted it, and Mol just looked up and yawned!! Maybe she did have a touch of arthritis - mind you, she is 18.