Klondike was born at the Denver Zoo in 1994 with sister Snow. The cubs' mother neglected them after birth and zoo veterinarians kept them alive until they outgrew the facility there and were taken to SeaWorld, the Orlando Sentinel said Friday.
Snow died last year.
Klondike had appeared in good health Thursday night, the last time his handlers saw him alive, though they reported he ate slowly, an oddity for the massive bear. He was found dead in his habitat Friday morning. Vets said they think Klondike died in his sleep.
Staff members have taken the death hard, park officials said.
"Klondike was part of our animal family," said Mike Boos, SeaWorld Orlando's vice president of zoological operations. "We have team members who have known Klondike since he arrived in 1995. They're sad and feeling the loss of this amazing animal."
Polar bears in the wild have a life expectancy of 15 to 18 years but have been known to live to 30 in captivity.
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