Partner preference of intact and ovariectomized female gray short-tailed opossums (Monodelphis domestica)

Intact, ovariectomized and ovariectomized estradiol (E)-treated female gray short-tailed opossums were placed in a test situation in which they could choose between an intact and a castrated male. Intact females chose to visit intact males first and visited them more frequently and spent more time with intact than with castrated males. Ovariectomized (OVX) females did not show this preference for visiting intact males over castrates. When compared to OVX females with blank implants, OVX females with E implants spent less time with castrated males. Like intact females, OVX and OVX-E-treated females preferred to stay in close proximity to but not actually in the cage of intact rather than castrated males. To our knowledge, this is the first experimental study of partner preference and its relationship to hormonal condition in a female marsupial.