The Akron Zoo is mourning the death of its male river otter Porthos.

The animal's heart stopped during a routine exam and he passed away after efforts were not able to revive him, the zoo announced Wednesday morning. It appears Porthos had a congenital condition.

“We are heartbroken over the sudden loss of Porthos,” Akron Zoo President and CEO Doug Piekarz said in a prepared statement. “Porthos was a wonderful ambassador for his species and we will all miss him. Thank you to our veterinary care staff for their heroic efforts in this difficult situation.”

The zoo’s female otter, Molly, will remain in the otter habitat daily.

Porthos was a favorite among zoo guests, the zoo said, as he would interact with people when they used the otter slide that goes through the otter habitat.

He was born March 19, 2010, at the Columbus Zoo and Aquarium. He arrived at the Akron Zoo in 2013 from the Dayton Boonshoft Museum for the opening of the Mike & Mary Stark Grizzly Ridge. The median life expectancy for North American river otters is 12 years.

The Akron Zoo participates in the River Otter Species Survival Plan. The program works to ensure the long-term survival of North American river otters through breeding and population management programs.