A 15-year-old lion has died at the Calgary Zoo while being anesthetized for medical checks, the zoo said Thursday.

Abena, one of the zoo's three female lions, had for the last three months been experiencing collapsing episodes that were increasing in frequency.

The zoo said in a release that Abena had her last full physical exam in July 2010, but no major health issues were identified at the time.

Veterinary staff suspected the frequent collapses were likely caused by cardiovascular disease, the zoo said.

In order to do a full cardiac assessment, the lion had to be anesthetized.

She died in the process, and a post-mortem exam revealed the lion suffered from a form of heart disease, liver disease and possible early stages of cancer, the zoo said.

The average life expectancy for female lions is 15 or 16 years.
3 black bears left at zoo

In a turbulent week at the zoo, a black bear was put down and a baby giraffe was born.

The male calf was up on his feet quickly after mom Carrie gave birth early Wednesday morning, and he has been nursing well, the zoo said.

The calf is almost seven feet tall and weighs 185 pounds, the zoo said.

On Tuesday, the zoo euthanized a 22-year-old black bear named Patches who was experiencing painful arthritis in her spine and joints. The zoo said the aged bear's arthritis was no longer responding to treatment.

There are three black bears left at the Calgary Zoo.