Orangutans use complex engineering skills to build nests in the Indonesian treetops
Students at the University of Manchester have published the results of a year-long study of man’s closest relative - the orangutan - in Indonesia which suggest that the apes may have evolved specialist engineering knowledge.
Overseen by Dr. Roland Ennos and carried out by PhD student Adam van Casteren, the research mission analysed how orangutans carefully selected twigs, branches and leaves, and constructed detailed nests night after night with a deftness and skill seen in the majority of engineering professionals.
Van Casteren explains: “We found that the orangutans chose strong, rigid tree branches for the structural parts of the nests that supported their weight, and weaker, more flexible branches for the nest’s linings, suggesting that the apes’ choice of branch for different parts of the nests was dictated by the branches’ diameter and rigidity.
“Further, branches chosen for the nests’ structural framework were fractured differently from those chosen for the lining: whereas structural branches were broken halfway across, leaving them attached, branches used for the lining were completely severed, suggesting that orangutans might use knowledge of the different ways in which branches break to build strong and comfortable nests.”
Male orangutans can weigh up to 80kg so the nightly nests must be strong enough to support this mighty burden. The apes construct these temporary shelters to prevent themselves coming into contact with predators or parasites during their sleep and upon waking, leave their beds and continue with their day.
Van Casteren took this opportunity to climb into the treetops and analyse the nests, often taking them apart to discover the tricks used by the intelligent apes. A conclusion by the research team suggested that these abilities to recognise material properties and mechanical design elements indicated ‘the evolution of tool use in early humans’.