Urinary volatile molecules vary in males of the 2 European subspecies of the house mouse and their hybrids.

Mice recognize other mice by identifying chemicals that confer a molecular signature to urinary marks. Such molecules may be involved in species recognition, and previous behavioral studies have related divergence of sexual preference between 2 subspecies of the house mouse (Mus musculus musculus and Mus musculus domesticus) to urinary odors. To characterize the differences between odors of males of the 2 subspecies and their first-generation offspring, the urinary volatile molecules were examined via gas chromatography coupled to mass spectrometry. Seven molecules were present in the samples from mice of at least one group. Their quantity varied among groups: M. m. domesticus showed a quantitatively richer panel of odorants in their urine when compared with M. m. musculus. The hybrids showed a more complex picture that was not directly related to one or the other parental subspecies. These quantitative differences may contribute to the specificity of the odorant bouquet of the 2 subspecies.