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.