Scientists investigate why Gorillas in zoos are dying from heart disease

Mopie looked the picture of ape fitness. He had a healthy appetite and was no couch gorilla, either.

Which is why the Washington, D.C.'s National Zoo staff were so stunned when, on the afternoon of July 3, 2006, the gorilla suddenly collapsed after playing with some newly introduced mates. By the time the keepers cleared out the other gorillas and tried CPR on Mopie, the gentle, 430-pound giant was lifeless - a victim of heart failure at 34.

'There was nothing to indicate he was feeling poorly or under the weather,' Lisa Stevens, curator of primates and giant pandas at the National Zoo said. 'That's what made it even more of a shock.'

Two days earlier, the National Zoo had lost its only other male group leader, a silverback named Kuja. Diagnosed just a month earlier with congestive heart failure related to cardiomyopathy, Kuja died while undergoing surgery to receive an advanced pacemaker. He was 23.

Sadly, Mopie and Kuja were not alone.

Gorillas in zoos around the nation, particularly males and those in their 20s and 30s, have been falling ill - and sometimes dying suddenly - from progressive heart ailments ranging from aneurisms to valvular disease to cardiomyopathy.

Now zookeepers are scrambling to understand might be done to save the 368 lowland gorillas that currently reside in 52 zoos across North America.

A 1994 study of 74 captive gorilla deaths, published by veterinarians Tom Meehan of the Brookfield Zoo and Linda Lowenstine of the University of California at Davis, found that 41 percent - and 70 percent of males older than 30 - were from heart disease, mainly fibrosing cardiomyopathy.