Berit, the female polar bear (Photo: Crissi Lanier)

Have you noticed the bald spot on polar bear Berit’s belly?


The Cincinnati Zoo’s female polar bear, Berit, recently had some of her white abdominal fur trimmed, exposing a small patch of her black skin. This is not the latest trend in carnivore fur-styles; instead, the purpose of this haircut is to facilitate ultrasound examinations of the 16-year-old bear to identify signs of pregnancy. Although Berit and male Little One have been together for multiple years, they have not produced any cubs; however, zoo staff has reason to hope that this year might be different.

Earlier this year, Berit failed to show signs of estrus during the normal polar bear breeding season. Rather than let another year pass with no chance of cubs, it was decided to intervene by administering hormones in an attempt to stimulate her ovaries, similar to what humans receive when they seek help with fertility issues. The two hormone injections appeared to be effective, because the pair began breeding soon after the treatment.

polar_ultrasoundBerit is one of the first bears ever to undergo infertility treatments and, even if these efforts fail to help her conceive, she still is advancing scientific knowledge by helping researchers at the Center for Conservation and Research of Endangered Wildlife (CREW) learn more about the unique reproductive physiology of this species. In addition to twice weekly ultrasound examinations (in which she voluntarily participates), her hormone levels are being measured non-invasively by fecal hormone analyses to monitor ovarian activity and indications of pregnancy. If Berit turns out to be pregnant, she would give birth towards the end of the year.

This work is part of CREW’s Polar Bear Signature Project, which aims to study polar bear reproduction and to help overcome reproductive challenges faced by this iconic species. Click here to support CREW’s polar bear research.