An aerial photo of an orangutan nest.
Orangutans spend much of their lives in the trees. At a very young age, they learn to construct nests from their mothers. When orangutans mature, they are a solitary species, moving through the forest and building nests in trees.
This past August, while on an ecotour in Borneo, I had the opportunity to observe an orangutan building a nest outside of Gomantong Cave. We also encountered remnants of old nests while tracking through Sepilok Forest. So I spoke with Dr. Marc Ancrenaz, a Sabah, Malaysia-based wildlife biologist and the Director of HUTAN (Kinabatangan Orang Utan Conservation Programme), to learn more about orangutans and their nest-building behaviors.
“All great ape species build night nests for sleeping,” Dr. Ancrenaz shared with me. “In general, they will build one every night, and some of them also build day nests for a quick rest.” Orangutans will occasionally reuse or improve upon an old nest.
But before building a nest, orangutans must pick a tree, and evidence suggests that orangutans are discerning in this matter. It seems that orangutans rarely construct night nests in fruiting trees, but may prefer to utilize tree species outside the fruiting period.
From a position up high in the tree canopy, orangutans have increased visibility into the forest, allowing them to be on guard from clouded leopards or on the lookout for a potential mate.
An wild orangutan nest in Borneo.
While day nests are frequently simple in construction, night nests can be quite elaborate structures. After selecting an appropriate tree, orangutans construct nests by bending and twisting carefully-chosen tree branches into a solid foundation. They layer smaller branches on top – often very leafy ones – to make a mattress of sorts. Then orangutans will stand in the nest and braid branches to ‘lock’ the structure in place. Some orangutans will even add accessories to their night nest – such as roofs, pillows and umbrellas – while making ‘nesting’ sounds.
An example of a new orangutan nest.
An old orangutan nest in a tree.
Orangutans more likely use nests for protection from weather, predators and parasites, in addition to added comfort while sleeping in trees. It’s possible these nests also have a role in mating and playing.
Check out this footage, captured by HUTAN, of wild orangutans building and spending time in their nests:
Photo and Video Credits: HUTAN, Kinabatangan Orang Utan Conservation Programme