Characteristics of the oestrous cycle and influence of social factors in grey short-tailed opossums (Monodelphis domestica)

Abstract

Characteristics of the estrous cycle of grey short-tailed opossums were studied by vaginal smears. The period of estrus was identified by a sudden proliferation of epithelial cells which lasted about 6 days (range 3-12 days), followed by a leukocytic infiltration. Estrous cycle length showed a bimodal distribution of 14.4 days (5 cycles, range 11-17 days) and 32.3 days (10 cycles, range 28-39 days). Females housed with males showed more days of epithelial cell proliferation than did females housed alone, and estrous periods tended to occur in synchrony, suggesting that social factors may influence the estrous cycle in this species.