Abstract

We document the influence of fetus orientation in the time invested in the birthing process of Antarctic fur seals at Cape Shirreff, Antarctica. Our results show that breeching was significantly higher than cephalic orientation on the order of 1.5:1. The average duration of the birthing process was 37.26 min, and the average duration considering the fetus orientation was 27.22 and 49.39 min for the cephalic and breech, respectively. The average time was significantly different only in the phase from the appearance of the amniotic-allantoids sac to the complete expulsion of the pup. Possible explanations for this difference are: the friction between the opposite hair direction with the uterus-vaginal wall after the rupture of amnio-allantoid sac during the transit of the fetus in breech position, and/or the fact one or both front flippers would increase the scapular diameter and make the final step of fetus delivery more difficult. © 2008 Springer-Verlag.