Anana, a 20-year-old female polar bear, was killed Monday at the Detroit Zoo by Nuka, an adult male bear, while attempting to breed.
Detroit Zoological Society chief life sciences officer Scott Carter said the bears had lived together without incident for part of last year. “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 Detroit Zoo said it had not had an animal kill another since 1988, which also involved polar bears.
After being apart for several months, Nuka, 16, and Anana were re-introduced last week as part of the Association of Zoos & Aquariums (AZA) Polar Bear Species Survival Plan, which "helps ensure the sustainability of healthy captive animal populations."
Nuka, who has lived at the Detroit Zoo since 2011, has lived with and bred with several other female bears without harmful behavior, the zoo said. Anana came to the Detroit Zoo in January 2020 and was introduced to Nuka at the end of March.