Female hamster rats were able to close up the entrance to the vagina.

During the study, the researchers followed 51 female hamster rats. In seventeen individuals, 23 cases of opening and re-closing of the vagina were recorded. The authors of the experiment noticed that when a female with an open vagina died in a colony where only females lived, seven of her neighbors opened the previously closed entrances. This happened within two months. This is probably how they reacted to the change in their status, because otherwise the living conditions remained the same. According to scientists, this study clearly shows that in some species of mammals, the reproductive system is plastic even in adulthood.