A female tiger at the Minnesota Zoo died unexpectedly this weekend.
The tiger, Nadya, hadn't been feeling well the week prior to her death, the zoo said in a Facebook post Monday.
Nadya, who was 3 years old, was being monitored by zookeepers and veterinarians around the clock, the post said. When her condition didn't improve, she went into emergency exploratory surgery.
She died shortly after the procedure, despite attempts to revive her.
Before she died, blood tests showed Nadya's liver wasn't working properly, the zoo said in a press release.
Results of a necropsy (the term for an animal autopsy) are still pending, the zoo said.
The zoo said wild tigers have a lifespan of 10-15 years, but didn't note how long the cats are expected to live in captivity.
'She was one of our favorite animals'
Nadya was an Amur tiger – she came to the Minnesota Zoo as a young cub from the St. Louis Zoo in the summer of 2012, according to the release.
She lived with a Minnesota Zoo-born cub named Sundai, the zoo said. Both cubs were hand raised because their mothers weren't able to nurse properly.
“We are very sad over the unexpected passing of Nadya,” Kevin Willis, the Minnesota Zoo’s vice president for biological programs said in the release. “Because she was hand raised here, she was one of our favorite animals and despite receiving the very best in medical care, she unfortunately didn’t survive. She will always be remembered by staff and volunteers as a sweet-natured tiger.”
With Nadya's passing, four tigers remain at the zoo: 3-year-olds Sundari and Patrice, 6-year-old Putin, and the oldest tiger, Molniy, who is 16 and currently being treated for age-related conditions including arthritis, the zoo says.