Asheboro, NC — In an extremely sad development for the gorilla program as well as the entire staff at the North Carolina Zoo, veterinarians were forced to euthanize 21-year-old male gorilla “Nkosi” Tuesday afternoon following more than a week of intense treatments and testing for an illness that has yet to be identified.

Nkosi, called “Nik” by his keepers, was best known as the father of two male youngsters, “Bomassa” and “Apollo,” born in August 2012—the first successful gorilla births at the N.C. Zoo in more than 23 years. Nik had been transferred to Asheboro from the Columbus (Ohio) Zoo in March 2008 as part of the Gorilla Species Survival Plan of the Association of Zoos & Aquariums.

According to Curator of Mammals Adrian Fowler, Nik became ill more than a week ago with symptoms that included headaches and loss of appetite. His condition had “waxed and waned” over the ensuing week until early Sunday morning when he “finally collapsed,” Fowler said.

“Despite the best efforts of the zoo’s veterinary and keeper staffs working round-the-clock, by Sunday morning Nik was unable to move, eat or drink,” Fowler explained. “Experts from other zoos as well as the human medical field were consulted on the case. But based on a variety of clinical signs and laboratory tests, in the end we had no other choice but to euthanize on humane grounds. His situation had become terminal.”

A necropsy, or animal autopsy, was being conducted Tuesday afternoon at the zoo’s Hanes Veterinary Medical Center. Tissues and other samples collected during that procedure will be sent to outside laboratories for further testing in an effort to help determine the nature of the illness. But results of those tests could take several weeks to obtain, Fowler said.

“This is an extremely sad day for the entire zoo,” said N.C. Zoo Director Dr. David Jones. “Our gorilla family has been one of our great successes over the last few years. Nkosi was a terrific father to Bomassa and Apollo and will be very difficult to replace.”

Meanwhile, the other gorillas in the N.C. Zoo’s collection, including Bomassa and Apollo, their mothers “Jamani” and “Olympia,” and a third adult female, “Acacia,” remain on exhibit and in good health.

The zoo is an agency of the N.C. Department of Environment and Natural Resources, John E. Skvarla, III, Secretary; Pat McCrory, Governor.