The modern Planet of the Apes reboot begins with a research chimpanzee being raised in an American home. It's a pretty plausible premise — that exact scenario has played out in the real world many times.
On June 26, 1931, for example, Luella and Winthrop Kellogg pulled a baby female chimpanzee away from her mother and brought her to live in their home in Orange Park, Fla.
The Kelloggs were comparative psychologists. Their plan was to raise the chimpanzee, Gua, alongside their own infant son, Donald, and see if she picked up human language. According to the book they wrote about the experiment, Luella wasn't initially on board:
... the enthusiasm of one of us met with so much resistance from the other that it appeared likely we could never come to an agreement upon whether or not we should even attempt such an undertaking.
But attempt it they did. The Kelloggs performed a slew of tests on Donald and Gua. How good were their reflexes? How many words did they recognize? How did they react to the sound of a gunshot? What sound did each infant's skull make when tapped by a spoon? (Donald's produced "a dull thud" while Gua's made the sound of a "mallet upon a wooden croquet ball.")
Chimpanzees develop faster than humans, so Gua outshone Donald when it came to most tasks. She even learned to respond to English phrases like "Don't touch!" and "Get down!"
But unlike the apes in the movies, Gua never learned to speak.
Donald, on the other hand, began to imitate Gua's screeches. "Whenever an orange or other desired food was observed and barked for by Gua," the Kelloggs reported, "Donald would usually take up this imitative call."
The Kelloggs decided to end the experiment after 9 months. But the era of ape language research was just beginning.
In the decades that followed, scientists kept trying to get apes to talk to them. That usually involved taking an intelligent, wild animal and forcing it to live out its life in an unnatural setting. No ape ever spoke, but some (perhaps most famously Koko — "The Gorilla Who Talks") learned to employ hand signs. Did those apes understand what they were signing? Were they really using language?
Skunk Bear's latest video explores footage and findings from decades of research. It might leave you questioning some of the more breathless claims about some of our closest, cleverest animal cousins.
Barbara J. King, who consulted on this video, has written a lot about ape cognition over on NPR's 13.7: Cosmos and Culture blog.