Endocrinologically- and socially-dependent volatile constituents of female mouse urine, identified in a previous study, were tested for their capability to accelerate puberty and extend the estrous period in young females. Several volatile ketones advanced puberty by approximately three days and extended the period of vaginal cornification in 55-75% of exposed females. High High concentrations of these substances were capable of overriding the known puberty-delaying chemosignals. Volatile cyclic enol ethers were also effective in extending estrus, but not puberty acceleration.