Why Primates Live Longer
After the holiday season, who doesn’t feel like their body is slacking in burning calories? But new research affiliated with the zoo suggests it’s a scientific fact…for primates at least.
Pound for pound, primates burn only half the energy of non-primate mammals. That’s the key finding of a new research paper authored by zoo collaborator Herman Pontzer, Ph.D., of Hunter College.
The output isn’t tied to activity. Instead, primate metabolisms seem to be fundamentally adapted to conserving energy. For example, I’m roughly the same size as one of the harbor seals at Kovler Sea Lion Pool (minus the blubber, of course). As Dr. Pontzer puts it, I would have to run a marathon every day just to match that marine mammal’s energy expenditure. This difference may explain why primates as a group develop, mature and, yes, die, much later than other mammals.
How do you measure an animal’s energy expenditure in the first place? Well, a portion of the water we drink is converted to carbon dioxide as the body produces energy. By giving animals a special—and benign—variant of water, we can track how much is excreted as urine and how much is exhaled as carbon dioxide. The last part—the carbon dioxide—gives us a barometer for metabolic activity.
Zoo chimpanzees Optimus Prime, Hank, Kathy and Chuckie and gorillas Kwan, Rollie and Azizi all had their energy measured in this manner. It wasn’t easy. The animals being studied have to be trained by our animal care staff to drink literally every drop of the special “doubly labeled” water. Afterward, someone has to be waiting to collect “the output” at the appropriate time.
But this kind of research reveals fascinating details about primates—and people. It helps us better understand the adaptations that make us unique. It can also deepen our understanding of the animals in our care. We were happy to see, for instance, the study revealing that zoo primates as just as active as their wild counterparts.
What’s next? With a grant from the National Science Foundation, Dr. Pontzer is teaming with the zoo’s Lester E. Fisher Center for the Study and Conservation of Apes to collect data from additional ape species. Zoo researcher Mary Brown is traveling to zoos throughout the country, collecting urine—and behavioral data—from orangutans at Zoo Atlanta or bonobos at Columbus Zoo. Closer to home, our animal care staff is working with white-cheeked gibbon Caruso in hopes of including him in the study.
That raises an important point—this kind of research is only possible with close collaboration between scientists and animal care experts. Indeed, Dr. Pontzer approached Lincoln Park Zoo because he wanted data from apes in naturalistic, engaging environments. We were happy to deliver on that score, just as we’re excited to share our expertise for the next stage.