Practicals teaching animal behaviour rarely work because of stressed out animals and naïve students. We take all the difficulty out of running your first animal experiment by using augmented reality fiddler crabs. With crabs that behave the “right” way each time and are immune to stress, students can focus on improving their understanding of experimental design and behavioural observations. Each crab has real measurements and behaviours which allow players to perform statistical analyses. This game replaces animal behaviour practicals and is best used in a class where individuals work in groups. It can also be used to teach students concepts surrounding animal behaviour in online courses. The augmented reality tags can be downloaded from the Arludo website here: https://arludo.com/game/reservoir-crabs Key words: Reservoir Crabs, contest dynamics, animal behaviour, fitness, statistics