Female rats prefer an area vacated by a high testosterone male.

In each of 4 experiments, female rats were observed as they moved freely about an apparatus that had recently housed 2 males. The androgen levels of the males were manipulated with castrations and exogenous injections of testosterone propionate (TP). For the most part, female exploration times in the areas vacated by the 2 males did not differ. The urinary markings over the urine from the males, however, did differ. The female exhibited a decided marking preference for the area that had housed the male with higher titers of androgens. The preferences were for intact vis-a-vis castrated males, though injections of TP restored the castrates' attractiveness to the females. When both males possessed reproductive levels of TP, the females preferred to mark over the urine of the male with the higher levels of the androgen. The reproductive advantage for the female may be the choice of a mate with more viable sperm, because androgens are intimately involved in spermatogenesis.