As the video above shows, large-bodied apes are extremely nimble, even on the highest tree branches. This does not, at first, make intuitive sense.
How are they so efficient so high up in the trees? Surely powering such a large body with enough energy should be a hindrance? Evidently, this is not a problem for apes.
To understand the energy costs involved for apes to move around their forested environment, researchers analysed the next best thing: parkour athletes, who are extremely agile and can climb up and down complex obstacles.
We're not as well-adapted as an orangutan
"They are as close to our ape cousins as we can manage," says lead author Lewis Halsey of the University of Roehampton in London, UK.
In order to measure their energy consumption they were fitted with an oxygen mask. This would be difficult and unethical with wild apes.
The athletes were given four chances to go around an obstacle course, and became more efficient each time. This is similar to the way orangutans become more adept as they move around the forest and climb familiar trees.
Further, the parkour athletes with the longest arm spans and shortest legs were the most efficient.
"That's rather like an arboreal primate," says Halsey. "These apes tend to have broad chests and long arms, which gives them a big arm span, and short legs." While their bodies are obviously not identical to those of parkour athletes, "nonetheless the pattern is somewhat similar".
The results reinforce the idea that "humans are still pretty well-adapted for the trees," he says. "We're not as well-adapted as an orangutan, we just don't have the shoulder flexion and grip strength. But nonetheless we are pretty good."
It also explains how such large-bodied animals can survive the energy costs required to navigate their complex environment. They have evolved ways to use minimal energy, with bodies well-adapted for trees.
The research is published in the Journal of Human Evolution.
Melissa Hogenboom is BBC Earth's feature writer. She is @melissasuzanneh on Twitter.
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