Odour recognition by male hamsters: discrimination of the hormonal state of females by odour from vaginal secretions

Abstract

Male hamsters were tested for their interest in females on different days of the oestrous cycle. Behaviour of males toward novel females was measured and (after exposure to vaginal secretion) towards females that matched or did not match that vaginal odour. Because pro-oestrous (day 4) females lay trails of vaginal secretion and will become receptive within a few hours, it was predicted that males would show more interest in day 4 than in other dioestrous females. While males showed no preference for novel, pro-oestrous females over dioestrous females, after pre-exposure to odour, their response to females was determined by the cycle day of the vaginal secretion to which they had been exposed. Males pre-exposed to vaginal odour from females carrying large implants of oestrogen preferred to spend more time with females who matched that vaginal odour than mismatching females and to sniff them more. This preference was not seen if the females carried small oestrogen implants or had no replacement oestrogen. This suggests that pro-oestrous females (who are known to have high circulating levels of oestrogen) can, by means of their scent-marking behaviour, attract and keep males nearby until they become receptive.

Precopulatory behaviour in the male hamster: effect of the 5α-reductase inhibitor 17β-N,N-diethylcarbamoyl-4-aza-5α-androstan-3-one

“…All three are reduced after castration, although they decline at dif¬ ferent rates, and can be restored by treatment with testosterone (Steel, 1982). In addition, male hamsters, after exposure to female vaginal secretion, will direct more attention to the donor of the odour than to other mismatching females (Steel, 1984(Steel, , 1985. The ability to make this discrimination is maintained by testosterone in castrated hamsters (Steel & Hutchison, 1986).…”

Steroidal modulation of scent investigation and marking behaviors in male and female ferrets (Mustela putorius furo).

“…Pheromones modulate inter- and intrasexual conspecific social interaction in many mammals by advertising gender, kinship, reproductive status, fitness, and social dominance (Heth, Todrank, & Johnston, 1998; Le Magnen, 1952; Rich & Hurst, 1998; Steel, 1985; White, Fisher, & Meunier, 1986). Many mammals seek out and investigate socially relevant pheromones.…”