PROVIDENCE, R.I., May 2 (UPI) -- The sudden death of Trixie, a polar bear at the Roger Williams Park Zoo in Providence, R.I., remains unexplained after a necropsy.
A necropsy -- an animal autopsy -- was performed on the 18-year-old bear Saturday, just hours after she stopped breathing during routine sedation, the Providence Journal reported.
With no clues from the procedure, zoo veterinarians hope they will be able to determine Trixie's cause of death by examining tissue samples from her kidneys, liver, heart and other major organs.
Trixie began to respond to the "reversal" drug administered to allow her to regain consciousness after she was transferred to the trailer that was to take her to the Indianapolis Zoo and Gardens. She was being moved to allow the Roger Williams' new polar-bear habitat to be completed in 2007. But zoo workers soon noticed she had stopped breathing.
Dr. Cheryl Cullion and another veterinarian climbed atop the 550-pound, middle-aged bear and administered CPR for 20 minutes to no avail.
"It's an extraordinarily sad day," said an emotional Zoo Director Jack Mulvena Sunday. "Trixie was a beloved bear and a beloved animal, not only here amongst our staff, but with our visitors. It's really with a heavy heart I address you here today."
The bear had undergone the same tranquilizing procedure a dozen times in the past without incident.
