Detroit Zoo officials say 'normal protocols' were followed in polar bear breeding attack

Detroit Zoo officials said Tuesday they followed guidelines in a breeding attempt between two polar bears that turned deadly this week.

"Normal protocols were followed, including ensuring compatibility of two individual animals," Christina Ross, a spokeswoman for the Detroit Zoological Society, told The Detroit News. "For almost an entire year, these animals lived together 24 hours a day and we observed no aggression."  


On Monday, 20-year-old Anana died when Nuka, 16, the zoo’s adult male bear, was attempting to breed with her, officials reported.

On Tuesday, Detroit Zoo Executive Director and CEO Ron Kagan talked about the incident on "The Paul W. Smith Show" on WJR-AM (76. He said the news has shocked him and the zoo's staff.

He and Ross both emphasized that polar bears can be aggressive with each other without warning.

 "When I take people into the wild, we sometimes see predators fighting," he said. "And occasionally, you see them fighting each other. You know, humans are not the only ones that kill each other, unfortunately."

It was the first time an animal at the site had killed another since 1988. The last occurrence also involved polar bears, the zoological society said.

According to Detroit Zoological Society Chief Life Sciences Officer Scott Carter, Anana and Nuka had lived together without incident in 2020.

There were apart for several months then reintroduced last week as part of the Association of Zoos & Aquariums Polar Bear Species Survival Plan, which works to sustain healthy captive animal populations.

Through the effort, Nuka fathered twin cubs recently born at the zoo, officials said.

Anana was owned by the Buffalo Zoo, and the Denver Zoo owns Nuka, Ross said Tuesday.  

"It is common for animals in AZA zoos to be placed 'on loan' with other AZA institutions," she told The News, adding polar bears do not have commercial value and are not bought and sold.

A polar bear (Nuka), plays with a evergreen tree inside his exhibit during Green Day at the Detroit Zoo.

The zoo notified the U.S. Department of Agriculture and Association of Zoos and Aquariums about the death, Ross said.

On Monday, staff "responded immediately to separate the bears when they observed Anana’s injuries," Ross said. "Nuka was coaxed into the polar bears’ indoor enclosure with food, even though Anana had already died."

When asked about the zoo's liability for the animal’s death, Ross responded: "We are responsible for all animals that live here. We cannot control an animal’s emotional state, and there was nothing in advance to suggest aggression. In the wild, polar bears obviously are large predators and can be aggressive to other bears."

According to the World Wildlife Fund website, polar bears are "the largest bear in the world and the Arctic's top predator," with males weighing as much as 800-1,300 pounds and having razor-sharp teeth.

In a statement Tuesday, Dan Ashe, the AZA's president and CEO, noted the Detroit Zoo death is a reminder of the risks involved in tending to the animals.

“Anana’s death is tragic, and we offer our sympathies to the entire Detroit Zoo community," Ashe said.