Orangutans in the wild build a new nest every day to sleep in at night. Researchers have studied a number of these nests and have also filmed nest-building orangutans.
Examing the nests and the nest-building process is how the scientists have tried to gain more insight into the ‘technology’ of the nests. The orangutan starts by organising branches, bending or breaking them to lay the foundation for the nest. At this stage, sturdy branches are used; these are often thicker and still flexible enough to bend but not break right away. Then a ‘mattress’ of thinner branches is made inside the nest. The centre of the nest gives way much more than the edges, making the nest comfortable and safe. The orangutans appear to choose their materials very carefully. The way the nest is built, say the researchers, seems to suggest that these animals are demonstrating a level of technical knowledge. Notably, the apes do not always build an entirely new nest; they also make use of the foundations of old nests. The thin, flexible lining is added to the sturdy outer frame of an older nest.
The British research has been published in the journal Proceedings of the National Academy of Sciences.