Orangutans show remarkably advanced engineering skills when making nests, researchers say.
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”.