Cincinnati Zoo
Cincinnati Zoo's Walter the warthog has died.
PHOTO: Meg Vogel/The Enquirer/Imagn Content Services
(CNN) —  

One of the Cincinnati Zoo’s most beloved animals has died.

Walter the warthog died unexpectedly Saturday, the zoo said on Facebook. He was 6.

“Walter was very popular with guests and beloved by Zoo employees,” the zoo said.

“Many of you got to interact with Walter when he was a young ambassador and was small enough to participate in the wild encounters program,” the zoo added. “He outgrew that role but continued to enjoy attention from visitors and responded enthusiastically when people called him by name when they saw him running around his home in our African Savannah.”

Walter did not display signs of discomfort before he died, making it difficult for zookeepers to diagnose any health issues, the zoo said. The warthog’s typical lifespan is 11 years.

Walter wasn’t behaving abnormally until Saturday, when he didn’t finish all his food.

“Since that’s quite unusual for Walter, vets examined him and found an extremely enlarged bladder that was most likely caused by a blocked urethra,” the zoo said.

Sadly, it was caught too late.

A necropsy will be performed to determine more about Walter’s cause of death.