Coby the cougar collapsed and died Tuesday afternoon at the Chattanooga Zoo of as-yet unknown causes.
A necropsy was done, but zoo officials are waiting to talk with University of Tennessee technicians to get the results, according to Zoo President and CEO Darde Long.
"This comes as a huge shock to all of us here at the zoo. Although 10 years old, Coby passed his recent physical with flying colors and was not exhibiting symptoms of any kind of illness," Long said in a prepared statement.
"Coby's unique and playful personality will be greatly missed by all of us here at the Zoo," she said.
Coby was one of two cougars at the zoo when the $160,000 Cougar Express exhibit opened in September 2005.
Coby and another cougar, Mia-Mia, had lived at the zoo for two years before that in the chimpanzee house after being brought to the zoo after the Tennessee Wildlife Resources Agency confiscated them from private owners.
Zoo officials said Coby often would allow zoo visitors an "up close and personal" look by jumping into a glassed-in crate built into the exhibit.
"Our hearts grieve for zoo staff and the numerous members of the community that loved him," said Friends of the Zoo board President Gary Chazen.
The 13-acre zoo has been rebuilding its image in the past year with the help of a $25,000 study by zoo consultant firm Schultz & Williams and additional recommendations from the Association of Zoos and Aquariums.
The board hired the Schultz & Williams firm following a spate of 10 animal deaths in three months from November 2010 through January 2011. At that same time and for several months afterward, the zoo was hit hard by United States Department of Agriculture zoo inspectors.
From September 2010 until August 2011, U.S. Department of Agriculture zoo inspectors pelted the zoo with five inspections and 21 "noncompliance" findings, including one observing that the zoo did not have enough hay on hand to feed animals even for a few days.
But the zoo's last USDA-posted inspection -- in August, 2011 -- gave the zoo a perfect record with no noncompliant findings. Similarly, a zoo-requested review by the AZA brought a list of improvement suggestions, and the zoo remains AZA accredited.
Schultz & Williams' report for the zoo called for five focuses toward improvement: strengthening organizational structure, improving revenue, improving business practices, reinforcing the board's role and developing a greater external focus for the zoo president and CEO.