By Dan Klepal
The Cincinnati Enquirer

Kidney failure is being blamed for the death of Ulaq, the 5-year-old polar bear that was found dead in the Lords of the Arctic exhibit April 8 at the Cincinnati Zoo & Botanical Garden.

The animal was considered a healthy, young male by zoo staff.

The initial necropsy, or post-death exam, did not reveal a cause of death and that led zoo officials to send samples of all the bear's major organs to two labs.

Results from both labs agreed on the cause of death.

Terri Roth, vice president of animal sciences at the zoo, said kidney failure isn't unusual in mammals.

But it is unusual in such a young polar bear, she said.

Polar bears normally live to about age 25 in captivity.

Roth said the death won't prompt any changes in the way animals are handled or examined at the zoo.

"There was nothing more we could have done," Roth said. "Being a young bear, it's possible he was born with some type of problem that took a while to materialize.

"Examining the animals more means you have to lay hands on the animals more. So there's a balance there between what's enough and what's too much."

Ulaq's death leaves two bears in the exhibit.

Roth said the zoo has no plans to add another polar bear in the immediate future.

"We do have the capacity to add another bear, and we might do that if there is a bear that needs space. But we're not going to pursue that right now."

Ulaq was buried on the zoo grounds.

E-mail dklepal@enquirer.com