(WXYZ) — The Detroit Zoo said 19-year-old male polar bear Nuka has returned to the zoo after a year away at the Toledo Zoo to expand the populations of polar bears.
According to the Detroit Zoological Society, Nuka was moved to the Toledo Zoo after a recommendation from the Association of Zoo and Aquariums Species Survival Plan (SSP). While he was at the zoo, he successfully mated with female polar bear Crystal and sired two cubs.
According to a new SSP, a new recommendation was that Nuka transfer back to the Detroit Zoo. The SSP is a "cooperative population management program that helps ensure the sustainability of healthy captive animal populations" and they say has been successful with many births of polar bear cubs.
Nuka had previously mated with female Suka at the Detroit Zoo and that resulted in the birth of twins Astra and Laerke on Nov. 17, 2020. Currently, there are only about 55 polar bears in 25 AZA-accredited zoos and aquariums, zoo officials said.
Zoo officials say Nuka also completed his quarantine period, and now they hope Nuka's return will result in the coupling with Suka.
The zoo also said that Nuka does not pose a danger to Suka or any other polar bear.
On Feb. 8, 2021, female polar bear Anana died during a breeding attempt at the Detroit Zoo with Nuka. Originally, it was thought that Nuka may have caused her death, but a review found that Anana died from advanced heart disease and she experienced acute heart failure or a fatal arrhythmia before or during breeding attempts.
"It was impossible to know that she had a cardiac condition called multifocal myocardial fibrosis, as she showed no clinical signs, and a 2020 medical examination noted no abnormalities in her heart function," officials say.
They did find wounds on Anana, but officials say it likely resulted from Nuka holding her with his teeth, which is typical during polar bear breeding. They also said he was observed moving around her habitat after she became unresponsive, likely because he was confused by her behavior.
