New York City's lone polar bear was euthanized over the weekend because of health issues.
The Wildlife Conservation Society said Tundra the polar bear had kidney failure and severe arthritis.
Both diseases are associated with old age.
The 26-year-old animal was born at the Bronx Zoo in 1991.
The median life expectancy for male polar bears in zoos is under 21.
The zoo says it does not plan to get another polar bear in the near future.