OKLAHOMA CITY (KFOR) – A popular resident at the Oklahoma City Zoo has died suddenly during a routine procedure.

Officials with the Oklahoma City Zoo and Botanical Garden are mourning the loss of Rocky, a male North American river otter.

Rocky died on April 21 while undergoing a routine veterinary procedure at the Joan Kirkpatrick Animal Hospital.

Zoo officials say during the procedure, Rocky went into cardiac arrest and did not survive.

Rocky arrived at the zoo in 2016 from Miller Park Zoo in Illinois.