Orangutans are some of the smartest primates on the planet, besides humans. They've been documented doing incredibly bright things, even with manmade tools, and their opposable thumbs help make this possible.
In this video, a completely wild orangutan with no prior experience with hand tools is seen using a basic saw to cut into a tree branch. She does so after observing a fake mechanical orangutan, which looks truly real until you study its careful movements, as it saws into a branch right beside her.
Interestingly, the animal takes pride in her work, as she can even be seen blowing the sawdust out of her cuts, and she can even be seen using her feet as leverage to help hold the branch while she saws into it.
Of course, since she's not a machine like the fake mechanical counterpart, she gets too tired to continue through the rest of the branch, while the mechanical orangutan just keeps on going in an almost mocking sort of way.