Abstract

Here we document the time involved and the influence of fetus orientation in the birthing process of Otaria flavescens. Our results show that breeching was significantly more frequent than cephalic orientation. The complete birthing process took in average 47.57 min, being the breech orientation significantly longest that the cephalic orientation, particularly from the time of appearance of the amniotic-allantoids sac to placenta in the vulva. Although the adaptive mechanisms involved in the complex process of evolution toward an aquatic life are ongoing, further study of birthing processes are recommended, which could in future provide indicators on such adaptive advantages.