A female polar bear at the Detroit Zoo was killed Monday by a male companion who was trying to breed with her.
Scott Carter, the Detroit Zoological Society's Chief Life Sciences Officer, said Anana, and Nuka, had lived together without incident in 2020.
“This was completely unexpected and the Detroit Zoo staff is devastated by the loss of Anana in this sudden and tragic event,” Carter said in a statement.
The incident was the first time an animal has killed another at the zoo since 1988, officials said Monday. The last instance also involved polar bears.
Anana came to the zoo in January 2020 and was introduced to Nuka in late March.
"After being apart for several months, Nuka and Anana were re-introduced last week as part of the Association of Zoos & Aquariums Polar Bear Species Survival Plan," zoo officials said.
The cooperative population management and conservation program aims to ensure the sustainability of healthy captive animal populations, officials said. Zoo representatives credited the effort in the recent birth of twin cubs Nuka fathered at the zoo.
Nuka has lived at the Detroit Zoo since 2011 as well as resided or bred with several other female bears "without showing harmful behavior," the zoological society said.
The zoo's other adult female polar bear, Suka, who had the twin cubs, is in a private maternity den with one of her cubs.
