Orangutans use sign language

Orangutans in different zoos use intentional gestures with specific meanings, "to initiate an interaction (contact, grooming or play), request objects, share objects, instigate joint movement (co-locomotion), cause a partner to move back, or stop an action."

Okay, so it's a zoo, not the wild, so they might have picked it up from how their human handlers act with them, but nobody intentionally taught it to them, so, Jesus, this is as impressive as knowing that vervets have vocalizations that distinguish having seen an eagle in the sky from a snake in the grass. It would be interesting to compare the gestures with how their handlers act with them.

It immediately makes you think about how human language began, step by step, a few calls, a few signs, a lucky mutation or two, more complex calls, and pretty soon you're planning a hunt or telling someone where the mongongo nuts are ripe.

And if anyone still has doubt, it puts paid to the notion of special creation. We and orangs and vervets came out of the same stock. Darwin wrote that every once in a while he would begin to think there was something special about people's creation, but then he would remember that human cognition evolved, and he would snap out of it.