— For better or worse, technological advancement has changed the world to the extent that at a professional level demands from the working executive required more hours either in the office or on business trips, on a social level the population (especially the younger generation) are glued to the computer either playing video games or surfing the internet. Traditional leisure activities, especially interaction with pets have been neglected or forgotten. This paper introduces Metazoa Ludens, a new computer mediated gaming system which allows pets to play new mixed reality computer games with humans via custom built technologies and applications. During the game-play the real pet chases after a physical movable bait in the real world within a predefined area; infra-red camera tracks the pets’ movements and translates them into the virtual world of the system, corresponding them to the movement of a virtual pet avatar running after a virtual human avatar. The human player plays the ga...