Pavlov is a virtual pet that encourages you to be physically active. He has ambient presence in the screens with which you interact. Pavlov is happy and healthy when you have walked a certain number of steps every day. When you are sedentary for a while, Pavlov nags you to take him out for a walk. He also craves to be the leader of all Pavlovs in your area. He can only be so when you, as his owner, become the most physically active person amongst your friends. Pavlov pings you every day at a certain time, telling you that he is going to have a dog-fight with other Pavlovs. You have the option to watch the dog-fight. Otherwise Pavlov simply tells you if he has won the fight, which may indicate that today you were more physically active than your friends.