An orangutan can grow to be over 260 lb. (118 kg) so how does one construct its nest up high in the trees? With great engineering skills, of course:
The researchers, led by scientists at the University of Manchester, followed and filmed the apes in the forests of Sumatra. The team also took orangutans' nests apart to see how they were constructed. Their study, in the journal PNAS, reveals that the apes select thick branches for a scaffold and thinner branches for a springy mattress.
Roland Ennos from the University of Manchester, a senior member of the research team, told BBC Nature that the behaviour revealed the animals' "sophisticated tool use and construction skills".
"They show a lot of engineering know-how in how they build their nests," he said.
As anyone who has ever tried to snap a live twig from a tree will know, living, green branches do not snap cleanly in half. Dr Ennos explained that the animals "made use" of this, bending and weaving large, flexible branches into a strong nest scaffold. The animals then filled this scaffold with fine, leafy branches - making a comfortable bed.