An Active Orangutan Burns Fewer Calories Than a Lazy Human

By Eliza Strickland | August 3, 2010 11:17 am

orangutanWhen an orangutan swings through the trees like an acrobat in its rainforest habitat, it’s burning fewer calories than a human couch potato.

A new study by biological anthropologist Herman Pontzer has found that oragutans use less energy, pound-for-pound, than any other mammal–except for that all-time champion of metabolic lethargy, the tree sloth.

“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,” Pontzer says. [NPR]

Pontzer worked with captive orangutans kept by the non-profit Great Ape Trust; the cooperative animals drank water that contained heavy isotopes of hydrogen and oxygen, and peed in cups for analysis. The researchers then checked the ratio of hydrogen to oxygen isotopes–the oxygen levels reflected how much CO2 the primate had breathed out during physical exertion, and allowed researchers to determine how many calories the orangutan burned.

The results, published in the Proceedings of the National Academy of Sciences, showed that a 250-pound male orangutan consumed 2,000 calories a day, which is 20 percent less than a typical human male. The two 120-pound females burned 1,600 calories a day.

Dr. Pontzer said the orangutans may have evolved this parsimonious metabolism to avoid starving when the ripe fruits that they eat periodically become scarce in their native rainforests. The evolutionary tradeoff is that orangutans grow slowly and reproduce at a low rate. [The New York Times]

For more on this story, see Ed Yong’s post on Not Exactly Rocket Science.

Related Content:
Not Exactly Rocket Science: Orangutans Are Masters of Conserving Energy
80beats: Study: Orangutans Play Leaf Instruments to Fool Predators
80beats: Syncopated Rhythm Makes Orangutans Masterful Swingers
80beats: Happy News: New Population of Endangered Orangutans Found in Borneo
80beats: Orangutans Are Threatened With Extinction as Habitat Shrinks

Image: flickr / ltshears

MORE ABOUT: orangutans, PNAS, primates
  • Rhacodactylus

    Poor guy, it’s gotta be hard not to take it personally when the benchmark they are using for your lethargy is the sloth.

  • Jay Fox

    It’s the price we pay for a big brain. Those orangutans are waayyy stronger than we are, and do it while burning fewer calories? This seems to say that exercise doesn’t help to burn that many calories, all things considered. Sure, the ape metabolism appears slower than ours, but where does their savings come from? For one, they’re not trying to maintain a big brain.

    Seems to me, if we want to lose weight, we should engage our hungriest element, the brain. Work those crosswords, and lose weight doing it!

    Has anyone noticed that those obese couch potatoes stare at what seems to be lower and lower quality programming all day long? The stupider the shows get, the fatter they become. I wonder what a study might show if one were to compare the type of programming viewed to overall body health. Would there be a statistical difference between those who watch science and documentary programming and those who watch cartoons and reality shows? Just my own observation, but if I want the (chubby) grandkids to leave the room, all I have to do is tune the TV to something “sciency.” They suddenly find other stuff to do.


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