"This is a heartbreaking loss for our staff and our visitors," said Brian Joseph, director of zoological operations for the Assiniboine Park Zoo.
Zoo officials said a gate was mistakenly left open. Baikal, an adult male tiger, found its way into a new enclosure, which was housing the zoo’s two younger male tigers named Samkha and Vasili.
Baikal and Vasili got into a fight that ended in Baikal's death earlier this morning.
Zoo officials told CBC a group of high school students were near the enclosure at the time.
Officials said they don't know how much of the confrontation students saw, but they think students may have known something was wrong.
Baikal had lived at the Assiniboine Park Zoo for the last five years.
With the loss of Baikal, three amur tigers remain at the zoo: Kendra, an adult female, as well as two-year-old brothers Vasili and Samkha.
The brothers were transferred to the Winnipeg zoo from Calgary in January.
Zoo officials are investigating the confrontation to ensure it doesn't happen again.
This is the second tiger death at the zoo in two years.
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