Med thumb ape evolution nests main

It may not seem like it, but bed making is an important ritual. By tucking the top-sheet in and putting the duvet back into its pre-sleep position, we begin our day by completing a task. This, experts agree,  is one of the simplest ways to start your day positively.  

As it turns out, our closely related ape cousins also appreciate the value of making their own beds. Except they don’t make their bed post sleep, and literally construct their entire bed each time they snooze. Great apes (gorillas, chimpanzees, bonobos and orangutans) all construct tree nests in which they’ll curl up or stretch out in each night — or day, depending. And while it seems like a simple act, bed-making is thought to have possibly been a key turning point in the development of early hominids — one small but significant step on the evolutionary road towards Homo sapiens.

Great apes are not the only primates to build nests, but they are distinctly different from others when it comes to how they use theirs. Small lemurs and bushbabies, for example, assemble leafy nests high up off the ground where they feed and groom their young. They also use these little structures to hide their young while they go out foraging for food. Some species even snuggle into nests with many individuals.

OrangutanNest

Conversely, Great apes erect new nests every night (or day, depending) solely for sleeping and only ever really share them with young. And whereas nest building is an instinctual behavior in strepsirrhines (lemurs, bushbabies, galagos and the like), it is a learned behavior in apes.

“The great apes all seem to have inherited the ability to make nests from their common ancestor 12 million years ago,” Roland Ennos, a biomechanics researcher and professor at the University of Hull in the UK told Van Winkle’s. Ennos, who has studied orangutan nest building, explained that it still takes plenty of practice and patience for young apes to master the technique, however, sometimes not reaching competence until about seven years old.    

He found that the orangutans experienced NREM, or deeper sleep — probably because they are able to sleep more peacefully in their nests up in the treetops compared to baboons that rest fretfully on the ground.

Even though all the great apes partake in the daily ritual of nest building, each species does so with its own touch. Gorillas, unlike the other great apes, like to change it up and build nests on both the ground and in trees, depending upon their surroundings, and even construct different types of nests for daytime or nighttime use. Daytime nests are generally simple assemblages of leaves and branches loosely piled on top of each other for napping, whereas nighttime nests are understandably much more involved.

Chimpanzees and their friendlier cousins bonobos tend to make fairly complex beds for nighttime sleep that are high up off the ground where the air is less humid, biting insects are less of a nuisance and where they are less likely to be snatched by a leopard in the dark. One study in Uganda even showed that some chimpanzees specifically choose branches from extremely sturdy hardwood trees that, when woven together, form a durable bed that can lock in place in the crook of a tree and ensure the deep sleeping apes won’t go tumbling to the ground at night while they’re adjusting sleep positions.

Despite chimpanzees handy work with hardwoods, however, orangutans probably deserve the major award when it comes to bed making in the world of the great apes. These red-haired primates of the islands of Borneo and Sumatra in Southeast Asia erect elaborate nests in the crooks of trees, sometimes 30 to 60 feet up off of the ground, that are complete with a “mattress” and a “pillow.”

Orangutans start by bending living branches together, which they half break, weaving them around each other to create a solid foundation — almost like a box spring — explained Enos.  They then pat down smaller, leafy sticks on top of them that make up what’s referred to as the “mattress.” Another pile of leafy greens and twigs make up the “pillow.”

“The [mattress and pillow] are not particularly impressive, but they must help make the nest a bit more comfortable, as the great apes sleep very soundly,” remarked Ennos. And as if this bed is not intricate enough already, some individuals cover themselves with foliage-filled tree branches when they tuck in for night.

Bed-making is thought to have possibly been a key turning point in the development of early hominids.

Bed-making is such a critical component of orangutans’ development that it is often the catalyst for infants to leave their mothers for the first time: when they can construct their own nest, they skidaddle. Like most other great apes, orangutans assemble a new nest every night. After years of this kind of practice, an adult orangutan can end up being able to fashion one in less than ten minutes.

“That’s amazingly quick and explains why they don’t reuse nests; it would take far longer to go back to the former nest site,” said Ennos, adding “Making new nests every day also means that parasites don’t build up.”

Great apes’ bed making also highlights what could have been a critical moment in human evolution. At some point around 12 million years ago in the Miocene period, apes’ common ancestor started constructing nests and sleeping in the canopies to get away from predators, blood sucking insects and humidity. It’s also very likely that as apes started getting bigger, they needed more support to be able to doze in a tree like monkeys can without falling out.

Orangutan

Studies on the role of sleep in our development as a species seem to suggest that safer sleeping quarters allowed for deeper sleep among apes and early human ancestors. Deeper, Non Rapid Eye Movement (NREM) sleep is believed to help increase cognitive ability.

One study in 2015, led by anthropologist Dave Samson from Duke University, compared brain activity in sleeping baboons to brain activity in sleeping orangutans. He found that the red-haired apes experienced NREM, or deeper sleep — probably because they are able to sleep more peacefully in their nests up in the treetops compared to baboons that rest fretfully on the ground in a seated position ready to spring away at a moment’s notice.     

The logic here goes then that human ancestors might’ve taken brain development a step further when they moved down out of the trees and started sleeping on the ground. Though the ground can be a dangerous place, early human ancestors like Homo erectus (active around 2 million years ago) might have already mastered fire — which would keep mosquitoes and predators away from individuals sleeping on the ground — and/or slept in caves and shelters; all of which provided protection, and in turn safer, sounder, and deeper sleep. Deeper sleep, perhaps, that further advanced brain development.

So the next time you faceplant onto your bed after a long day , know that somewhere else in the world, an ape cousin of yours — one of the original bed makers  — is doing the same in a bed of its own. It just happens to be a pricklier one.