Macho pheromones rile fellows
By Nathan Seppa
Two male mice often fight when put in a cage, but if one is neutered they get along fine. Decades ago, scientists found out that dabbing urine from an intact male mouse on the back of a neutered mouse gave the latter the chemical signature of an unaltered male. The neutered mouse soon found himself brawling with the guys.
Combining this behavioral test with modern biochemical analyses, molecular biologist Lisa Stowers and her colleagues at the Scripps Research Institute in La Jolla, Calif., now reveal some of the chemistry behind the aggression.