LinkNew diet for gorillas at Cleveland Metroparks Zoo helps animals with needed weight loss
CLEVELAND, Ohio -- New diets for two male gorillas at the Cleveland Metroparks Zoo earlier this month are bearing fruit for hundreds of captive gorillas in North America.
Bebac, 26, and Mokolo, 23, are Western lowland gorillas and both have heart disease. Their latest cardiac exams earlier this month, overseen by Dr. Albert Lewandowski, the zoo's chief veterinarian, showed healthy weight loss for both.
The diets responsible for the progress are Cleveland's contribution to a much larger project among more than a dozen of the best zoos in North America, all accredited by the Association of Zoos and Aquariums.
The challenge is that there is limited information on just what constitutes a healthy gorilla, according to Dr. Pam Dennis, a veterinarian and epidemiologist at the zoo. She is working closely with Dr. Kristin Lukas, an animal behavior expert who is the zoo's curator of conservation and science. She also chairs the association's 'Species Survival Plan committee.
Lukas and Dennis said there are 342 Western lowland gorillas at 52 North American zoos and about 100,000 in the wild.
They concede that the heart disease afflicting Bebac and Mokolo -- and many other gorillas -- cannot be cured. But their work can help to slow its progress and light the way to preventing the disease in others.
First steps were taken in 2008 when the zoo started weaning the simian duo off the commercial, processed biscuits that made up the bulk of their diets.
Vegetables and leafy greens became their staples, and the food was scattered about their enclosure so they were compelled to forage. Dennis said researchers believe the gorillas are now enjoying an activity level that is more akin to what they would have in the wild.
Another benefit of the diet is the complete eradication of a visually offensive habit that occurs in captive gorilla populations called "R and R," short for regurgitation and re-ingestion. Dennis and Lukas said it has not been observed in the wild and occurs among captives because of some element of the typical zoo diet.
Dennis believes the low-starch content in their new diets may be the key.
But some of the results of their latest cardiac exams are mixed, which Lukas called "a little sobering."
The good news is that Mokolo's heart chambers are now slightly smaller, his heart-pumping efficiency has improved, and he has lost 60 pounds since his last exam. The bad news is that the walls of his heart have thickened, and he has high blood pressure.
Bebac, who lost 20 pounds, experienced a decline in his heart-pumping efficiency and suffers from low blood pressure.
One important element of the Cleveland research belongs to Elena Hoellein-Less, a doctoral candidate in biology at Case Western Reserve University. She is trying to establish indicators for healthy body mass in the gorillas.
Dennis explained that veterinarians have historically relied on data about human body mass and heart health and tried to extrapolate that to apply to the gorillas, but indicators for 170-pound humans are difficult to adjust for 400-pound gorillas. Further, she said little is known about the health and mortality of "free-ranging gorillas because they tend to be fairly elusive."
The median age of captive gorillas is around 30, Dennis said, though Timmy, who once lived at the Metroparks Zoo, is alive and doing well at 51. She thinks the median age of endangered gorillas in the wild may be in the 20s because of disease and bush-meat hunting, among other factors.
In light of this article, do you think London Zoo fed Yaboah (who died from a heart attack) the kind of pellets/biscuits that are now suspected of giving the primates heart complications? The unpleasant phenomena "R & R" is a new one to me, where the captive gorillas become bulimic and can even eat their own vomit.
