immediately after the fight and is displayed by the mouse that was defeated in the fight. The defeated mouse, if allotted space, will run away and try and take shelter from the victorious mouse. If it is not possible for the mouse to physically run and escape because space is not available, the defeated mouse will rear up on its hind legs and hold its front legs up in a way that is characterized as a "submissive stance". These are examples of the physical behaviours that are responses to conflict in mice. Evolution and ecology of agonistic behaviour: Stomatopoda (praying mantis shrimp) Agonistic behaviour is a result of evolution, and this can be studied in a number of species facing different environmental pressures. Though agonistic behaviours can be directly observed and studied in a laboratory setting, it is also important to understand these behaviours in a natural setting to fully comprehend how they have evolved and therefore differ under different selective pressures. Mantis shrimp, predatory crustaceans, are an example of an aggressive and territorial organism whose agonistic behaviour has been studied in an ecological and evolutionary context. Mantis shrimp are among the world's most aggressive crustaceans. These sea creatures are secretive, but highly alert and active predators who inhabit burrows and cavities along coral reefs, rocky coasts, and muddy shores of tropical and subtropical waters. Roy Caldwell and Hugh Dingle conducted research on mantis shrimp and other stomatopods, which focused on the evolution of agonistic behaviour and how it applies to the ecology of these organisms. Agonistic behaviour has co-evolved alongside biotic factors such as body morphology, competition both within the species and against other species, and the habitats that these shrimp inhabit. Stomatopods arose from leptostracan stock, as is indicated by fossil evidence, approximately 400 million years ago. Morphology of stomatopods is consistent with most malacostracans in that they have three main body segments: the cephalon, the thorax and the abdomen. The abdomen is made up of six segments, five of which possess a pair of pleopods, which are used for respiration and swimming. The key appendage used by stomatopods for fighting behaviour is referred to as the raptorial appendage, which is actually a pair of enlarged second maxillipeds just behind the maxillae. These strong maxillipeds are used for purposes of prey capture in addition to fighting. The morphology of this appendage, particularly the propodus and dactyl which extend