Developmental and activational effects of sex hormones on the attractiveness of dog urine

Abstract

Adult male dogs were exposed to urine from five types of experimental donors: females ovariohysterectomized as adults (FOA), females treated with testosterone in utero (FTU), females treated with testosterone in early infancy (FTI), females treated with testosterone in utero and in early infancy (FTUI), males castrated as adults (MCA); and also to control urine from intact stud males (SM). Urine was collected from the five experimental groups of donors during three phases of the experiment: (a) during a period of no hormone treatment (NH); (b) following treatment with estradiol (E); and (c) following treatment with testosterone (T). Intact males were given no hormonal treatment and served as subjects and urine donors. Subjects spent about the same amounts of time investigating control SM urine in all three phases. In the NH phase, the investigation times for the five experimental samples were significantly greater than that of the SM sample. However, there were no significant differences between the investigation times of the five samples. During the E phase, in comparison with the NH phase, the investigation times were greater for all experimental samples. The increase in attractiveness was significant for FOA and FTU urine. During the T phase, compared with the NH phase, the investigation times were less for four experimental samples (FTU, FTI, FTUI and MCA urine), and FTI, FTUI and MCA urine were no longer preferred to the SM control. However, the decrease in attractiveness was significant for MCA urine only.