Behavioral selection of odor cues by young female mice affects age of puberty

Female house mice were reared from weaning at 21 days of age until first vaginal estrus in 40 1 aquaria in which they were given a choice of exposing themselves to bedding placed on opposite halves of the aquarium floor and sprayed with water or urine containing puberty-influencing chemosignals. In Experimental 1, mice housed with only male urine cues sprayed on the bedding matured significantly earlier and mice housed with only grouped female urine sprayed on the bedding matured significantly later than control mice where water was sprayed on the bedding for both halves of the aquarium. In Experiment 2, there were no significant differences in mean ages at vaginal introitus or first estrus for females reared with choices between (a) bedding sprayed with male urine versus bedding sprayed with water, (b) bedding sprayed with urine from grouped females versus bedding sprayed with water, (c) bedding sprayed with male urine versus bedding sprayed with urine from grouped females, or (d) the control condition where both sides of the aquarium contained bedding sprayed with water. Analysis of continuous video tapes of the locations of the females for Experiment 2 revealed that females chose initially to spend more time on the half of the floor with bedding that delayed puberty relative to the other side, but shifted their preference toward a more puberty-enhancing signal at about the time of first estrus. Female house mice appear to be able to exert some behavioral control over their own sexual maturation.