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Orangutans are engineers

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New reseach shows that orangutans posses high levels of intelligence and are able to engineer nests that involve forethought and an understandign of how wood breaks. (Photo: Michael Hoefner/ File)

Orangutans create sturdy and elaborate nests in treetops each night to sleep safely and comfortably. Scientists at the University of Manchester spent a year studying the physical properties of these nests and found the great apes are skillful and knowledgeable engineers.

Orangutans chose particular branches for different uses, and also broke the branches in different ways depending on their purpose. For the structural framework of the nest, they chose strong, rigid branches that could support their weight. They bent or broke nearby branches halfway across, leaving them attached, and wove them in place to build the nest's foundation. Next, orangutans fashioned a 'mattress' layer our of smaller, more flexible branches, which they severed completely from the tree and twisted together.

This suggests the apes are acting with forethought, choosing different branches for different purposes based on the branches' diameter and rigidity. Mechanical testing showed the structural branches are four times stronger and four times more rigid than the mattress branches. Those branches are thinner and more flexible, presumably to make the nest comfortable.

Orangutans can also personalize their nests, Some create blankets from large leaves, or pillows from leafy branches clumped together. They can even make roofs or secondary nests over the main one.

This study shows orangutans have some knowledge of the mechanical properties of wood and the different ways in which branches break, and make use of that knowledge in sophisticated ways.

Orangutan intelligence is sometimes overlooked. In other great ape species, like chimpanzees and gorillas, their complex social environment is often credited with driving the evolution of intelligence. The authors of this study suggest an animal's mechanical environment can also drive the evolution of intelligence. Orangutans tend to be more solitary than other apes, but this study demonstrates they interact with and manipulate their environment in a complex and clever manner.

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New reseach shows that orangutans posses high levels of intelligence and are able to engineer nests that involve forethought and an understandign of how wood breaks. (Photo: Michael Hoefner/ File)
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