A zoo keeper presses a heart monitor to the chest of one of Riverbanks Zoo’s gorillas. (Photo courtesy of Matt Perron/Riverbanks Zoo & Garden)

Two of the seven gorillas at Riverbanks Zoo & Garden are at risk for heart issues, and another has heart disease.

Heart disease is the most common cause of death for adult gorillas. It kills more than 40% of the male species in North American zoos, according to Smithsonian Magazine.

It’s known that obesity and insulin resistance are two of the main causes of heart disease among captive gorillas.

But experts are still learning about the illness.

“Heart disease is common in all the great ape, but we do not have a clear understanding of the underlying processes that contribute to disease,” said Martha Weber, the zoo’s director of animal health. 

The gorilla keepers at Riverbanks are caring for the gorillas with heart problems in several ways.  

They recently performed ultrasound exams.

Ultrasounds are performed at least once a year to keep track of the gorillas’ heart conditions. The keepers give the gorillas incentives such as treats and positive reinforcement to teach them to be comfortable with the heart monitors on their chests. 

“This allows us to monitor heart health without having to anesthetize the gorillas,” Weber said.

Sedating the gorillas slows down their heart rates, which would interfere with the tests, said Matt Perron, Riverbanks’ public relations manager.

Gorillas are also sometimes trained to present their chest for screenings, show an arm for injections or allow for blood pressure readings on their fingers to avoid sedation, said Greg Peccie, director of animal care and welfare at Riverbanks.

The gorillas with heart issues are reaching old age. 

The gorilla keepers are most concerned about, Cenzoo, just recently celebrated his 27th birthday on Feb. 2.  That means he need to be tested more regularly, Perron said. 

Patrick and Acacia, ages 32 and 28, respectively, don’t have heart disease like Cenzoo. But they have a history of other heart issues. 

Cenzoo, Patrick and Acacia are given beta-blockers to help regulate their heart rates, reduce blood pressure and prevent heart attacks.

Riverbanks also is planning to construct a new climbing structure in the Gorilla Base Camp exhibit, the zoo’s indoor viewing area for gorillas. The staff hopes that will help keep the gorillas active and prevent future heart issues from developing. 

The gorilla keepers’ main goal is to ensure the animals’ health is the top priority. 

“It’s all to keep an eye on the heart health of our animals and the gorillas in particular because they do have a history of heart conditions,” Peccie said. 

The gorillas live longer and healthier lives under the keepers’ care, Perron said. 

And it’s good for the staff members, too. 

“This isn’t a job for most of us,” Perron said. “This is a family, and the animals are part of it, so that’s why we’re here and what our mission is.”

The front entrance of Riverbanks Zoo & Garden, which visitors see when driving past. (Photo by P.J. Williams)

Cenzoo is the only gorilla who has heart disease. (Photo by P.J. Williams)

The visitors viewing area inside the Gorilla Base Camp (Photo by P.J. Williams)