Organization and expression of agonistic and socio-sexual behavior in golden hamsters over the estrous cycle and after ovariectomy.

Pairs of hamsters were housed in large enclosures that contained separate male and female living areas and observed over the 4-day estrous cycle and after ovariectomy. Agonistic elements exhibited frequently by females included on-back, boxing, lateral posturing, and biting, whereas males engaged frequently in boxing and on-back patterns of behavior. Furthermore, on-back and boxing by females were significantly higher on estrus than on any other day of the estrous cycle. Agonistic acts performed after ovariectomy did not differ in occurrence from those shown by animals on diestrus and proestrus. Vaginal marking increased during diestrus and attained a peak 24 hr prior to sexual receptivity. Both vaginal marking and mating occurred more frequently in the female's than male's home area suggesting that vaginal marking and mating occurred serve to attract males to the nest of females. Males also organized their marking patterns by location as shown by more flank marking in their own than their partner's area, albeit the significance for this difference in location is not known. The results demonstrate that when heterosexual pairs of hamsters are tested in large and partially familiar habitats, a wide range of behavior is exhibited and organized in a manner that is not observed in small and unfamiliar cages.