Buy CFLs. Unplug electronics. Take cold showers. These are some of the ways humans are told to be more energy efficient.
But what about the human body itself? Can our cells, organs and systems ever function in a less wasteful way?
For the answer, humanity would be wise to stop, pivot, and peer back down the evolutionary ladder—at the orangutan.
Mankind’s hairiest predecessors are extremely energy efficient.
According to a study published in Proceedings of the National Academy of Sciences, orangutans burn less energy, pound for pound, than almost any other mammal.
"You and I sitting in front of our computers use more energy each day than these orangutans that are walking around, and climbing around and socializing around their big enclosures," said one of the report’s authors, biological anthropologist Herman Pontzer, to NPR.
The heaviest male orangutan studied—he tipped the scales at just over 250 pounds—consumed a scant 2,000 calories per day. That’s 20 percent less than a typical human male.
Pontzer and his team conducted their research at the Great Ape Trust, a Des Moines, Iowa, center dedicated to the study of great ape culture and behavior.
Discover explains how researchers measured the orangutan’s energy input/output levels.
The method involves doubly-labelled water, made of rarer and heavier versions of the normal hydrogen and oxygen atoms. These heavy atoms can be tracked as they make their way through the body, whether they end up in the animal’s urine or in the carbon dioxide it breathes out. In fact, the amount that ends up in these two waste products is related. So by taking regular urine samples, Pontzer could work out how hard the orangutans were breathing out, and thus how much energy they were using up.
The two-week study showed that the orangutans used less energy than every mammal on Earth—save the three-toed sloth.
Pontzer and his team aren’t quite sure why the big apes are happy with the minimal diet, but there are theories—mostly that the metabolisms of the orange apes have adapted over the ages to “the boom-and-bust cycles of their food supply in South Asia,” reports Wired.
Scientists estimate that man and the orangutan last shared a common ancestor between 12 and 16 million years ago.
Photo: Longhorndave/Creative Commons via Flickr