This video shows the resident-intruder paradigm in rats. This test is a standardized method to measure offensive aggression, defensive behavior and violence in a semi-natural setting. The use of the paradigm for social stress experiments is explained as well.
Koolhaas, J. M., Coppens, C. M., de Boer, S. F., Buwalda, B., Meerlo, P., Timmermans, P. J. The Resident-intruder Paradigm: A Standardized Test for Aggression, Violence and Social Stress. J. Vis. Exp. (77), e4367, doi:10.3791/4367 (2013).