The 25-year-old bear died Thursday at the Denver Zoo. He had been under veterinary care for liver cancer. The bear was euthanized after veterinarians determined that he lost his quality of life due to an irreversible medical condition.

"This is never an easy decision, but it was the right one. We watched Frosty closely and saw his condition deteriorate rapidly. His quality of life had deteriorated to the point that he was not able to sustain a healthy weight and he was not going to get better. We'll miss him terribly," said Senior Veterinarian Dr. Felicia Knightly.

Frosty was born at Cleveland Metroparks Zoo and came to Denver from Tulsa Zoo in 2006.

The Denver Zoo lost another polar bear in April. Voda died from renal disease. She was 23 years old.

The longevity of polar bears is 20 to 25 years.

The zoo still has two other polar bears females Soosha and Cranbeary.

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