Parkour athletes act like orangutans for science

If you're a large, tree-dwelling ape like an orangutan, what's the best way to get across a gap in the branches? Should you jump or swing across, or maybe climb down and cross the gap on the ground? Scientists suspect the ape's decision will depend on which method uses the least energy, but that has been difficult to study because orangutans are endangered and elusive. So a group of researchers in the U.K. turned to a different kind of ape: humans.