Taiga, one of the zoo's male Amur tigers, had been suffering from rapidly deteriorating health over the last few days and had not responded to veterinary treatment, the zoo announced Wednesday.

A necropsy revealed evidence of previously diagnosed chronic renal failure and large tumors in his spleen, according to the zoo. The poor prognosis, the decline in quality of life, and the advanced stage of his renal disease were the factors in the zoo's decision to put the tiger down. Taiga was 15 years old. He came to Zoo Boise from Chicago’s Lincoln Park Zoo along with his brother, Tundra, and quickly became one of the zoo's most popular attractions.

Taiga has quite a back story. He was the tiger that mauled a zoo visitor in the summer of 2000. The zoo's then-manager David Wayne had taken a group of zoo visitors into the tiger cage area to watch keepers feed the animals during the "Feast for the Best" fundraiser event. Taiga escaped through an open doorway and mauled a woman. She suffered injuries to her head and neck, and was also accidentally shot in the leg by police officers who were trying to stop the attack. The city ombudsman cleared the officer who fired the shot. A police report found Wayne at fault for the attack. He was reassigned to other duties.

In addition to Taiga, Zoo Boise has two tigers, Tundra and Katarina. Katarina, a 9-year-old female came to the zoo in 2011 in anticipation of replacing the aging tigers.

There are no immediate plans to replace Taiga with another tiger.