Syllable composition of B6 and 129 males was not affected by the female strain. (a) The ratio of each syllable type for 129 and B6 male mice stimulated by a 129 female. The syllable composition pattern was consistent with Fig. 1 (stimulated by B6 female). (b) Time spent sniffing (left) and total number of syllables (right) during sniffing behavior. B6 and 129 males stimulated by 129 female. * p < 0.01.