King of the Swingers

As a famous character in a great Disney cartoon once sang about, it turns out that Orang utans really are king of the swingers because they know just the right way to swing their way through the forest without wasting too much energy.

That's according to a new study published this week by a team of scientists from Birmingham University, here in the UK.

To get around the forest and move across the gaps between trees, orang utans can't simply climb along to the end of a branch and grab onto another branch of the next tree because they are too big and the thin branch ends wouldn't hold their weight.

Also, dropping down to the ground, walking along to the next tree and then climbing up another tree or a vine is also not a great option either, because it exposes the orang utans to predators on the ground like tigers.

Instead, what scientists watching orang utans in the wild have discovered is that the great orange apes bridge the gaps between trees by choosing young trees with springy bendy trunks which they rock backwards and forwards in any direction they want - a technique known as tree sway. If they swing far enough they can then grab onto the branch of the next tree and relatively effortlessly continue their journey.

The researchers estimated that the orangutans use about half the energy using their tree sway method compared to jumping directly between trees and only one tenth the energy they would have to use if they climbed down to the ground each time they wanted to move across a gap.