Synthetic pheromones that promote inter-male aggression in mice

Two volatile constituents of male mouse urine, dehydro-exo-brevicomin and 2-(sec-butyl)-dihydrothiazole, have been found active in bioassays of inter-male aggressive behavior. The two synthetic compounds act synergistically when added to castrated male urine but not when added to water, and they provoke fighting that is quantitatively and qualitatively comparable to that elicited by intact male urine.