The squeal as an indicator of aggression in mice

Fighting behavior of paired male mice was observed while automatic recording equipment counted the squeals. A strong positive relationship was found between the squeals and other measures of fighting. The results are discussed in terms of the validity of squeals as a measure of aggression and the usefulness of the squeal measure and the advantages it provides, i.e., the possibility of continuous monitoring of fighting behavior, elimination of O effects, less handling of Ss, and use of a “home cage” type of environment.