Researchers have recently discovered that (just like humans) orangutans will resort to miming to communicate with their human counterparts.
Recently they have observed an orangutan using her palm to mime opening up a coconut, in the hope that her human companion will use his machete to do just that. They also mimed the action of being scratched to get an itch attended to and enacted opening a termite nest to prompt a partner to help. Often, the primates resorted to mime after other methods of communication had failed, showing that primate communication is far more complex than previously thought.
This was certainly witnessed firsthand on one of our recent orangutan tours. During a tropical shower in the forest, our clients were taking shelter under umbrellas before the female orangutan and her infant picked up a thick set of branches to keep themselves dry.
There are still a few places left on our December Orangutan Photography tour, so you can see firsthand the intelligence of the most enigmatic of primates.