Nora, a polar bear who formerly lived at the Oregon Zoo, has gained 237 pounds in recent months as keepers at Wisconsin’s Henry Vilas Zoo monitor her for a possible pregnancy.
Keepers Monitor Nora for a Possible Pregnancy
The zoo announced Thursday that Nora’s weight increased between March and September, a potential sign of pregnancy and preparation for denning.
Polar bears cannot be reliably pregnancy-tested, and ultrasounds are ineffective because the bears’ thick layer of insulating fat prevents clear imaging, according to the zoo.
Nora’s keepers are keeping a close eye on her, and her denning suite’s camera system has been upgraded. The first few weeks of a cub’s life are especially risky, the zoo said. First-time mothers such as Nora also face higher cub mortality rates than bears that have given birth previously…