Detroit Zoo Welcomes Back, Nuka, One Of Zoo's Polar Bears

ROYAL OAK, MI — A familiar face returned to the Detroit Zoo last week.

Nuka, an 18-year-old polar bear, is back at the zoo after spending last year at the Toledo Zoo, where he successfully sired two cubs with female polar bear Crystal, officials said.

Nuka’s transfer back to the Detroit Zoo was recommended by the Association of Zoo and Aquariums Species Survival Plan, which is a cooperative population management program that helps ensure the sustainability of healthy captive animal populations, officials said.

While at the Detroit Zoo from 2011 to 2022, Nuka mated with a female polar bear named Suka who gave birth to twin polar bears, Astra and Laerke, on Nov. 17, 2020, officials said.

Now, zoo officials are hoping Nuka will be able to successfully couple with Suka again this time.

Officials initially thought Nuka may have caused the death of another female polar bear Anana, who died during a breeding attempt at the Detroit Zoo on Feb. 8, 2021.

However, officials determined in March 2021 that Anana died from an advanced heart disease. An Analysis of Anana’s heart tissues showed that she experienced acute heart failure or a fatal arrhythmia before or during breeding attempts.

Officials said it was impossible to know that Anana 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 were initially concerned about Nuka because he was moving around the habitat after Anana became unresponsive, possibly because he was confused by her behavior, officials said.

Anana also had wounds, but officials believe they were from Nuka holding her with his teeth, as is typical during polar bear breeding.

"Having followed all the proper procedures and investigated the matter fully, Zoo experts have no reason to believe Nuka is a danger to Suka or any other polar bear," officials said.

There are roughly 55 polar bears currently living in Association of Zoo and Aquariums accredited facilities across the country. The Detroit Zoo is "thrilled" that Nuka is back so he can continue to help ensure the future of polar bears, officials said.