On March 28, 1838, Charles Darwin paid a visit to the London Zoo. At age 29, he was far from the scientific celebrity he would eventually become. It had only been two years since his return from his round-the-world voyage on the Beagle, and he was still methodically working his way through the heap of fossils and living specimens he had accumulated along the way. It would take more than two decades before he would present the world with his theory of evolution. In 1838, the theory was still in a primordial form in his mind. Darwin was struggling to find an explanation for how living things–humans included–got to be the way they are. And so, on that chilly spring day, Darwin went to the zoo and stepped into a cage with an orangutan.
It’s the sort of moment that was made for Hollywood. Indeed, when Hollywood turned its attention to Darwin, with the 2009 movie Creation, the actor Paul Bettany recreated the scene by climbing into another cage with another orangutan. And that image ended up on the posters for the movie, a powerful allegory for our reckoning with the fact that we are cousins to other apes.
Hollywood certainly gets lots of stuff wrong about science on a regular basis. But, in this case, Hollywood deserves some credit. This scene really did happen, and it really did have a profound impact on Darwin–and, by extension, on science.
Darwin’s biographers have retold the scene several times. They’ve relied on a few key pieces of evidence to reconstruct it, such as a letter Darwin wrote to his sister Susan after his first visit to the zoo, along with mentions in his books The Descent of Man and The Expression of Emotion in Man and Animals. Yet even today, 177 years later, there’s still much to learn about Darwin’s fateful encounter. In the journal Studies in History and Philosophy of Biological and Biomedical Sciences, John van Wyhe, a historian at the National University of Singapore, and Peter C. Kjaergaard of the Natural History Museum of Denmark present previously unpublished notes that Darwin scribbled down about the London Zoo’s orangutans.
In 1838, orangutans were still frighteningly unfamiliar to Europeans. In fact, all the great apes were a mystery because they lived thousands of miles away, deep inside African and Asian jungles. Early European explorers would report encounters with fierce, human-like creatures, usually told second-hand. In the early 1600s, a Dutch physician named Jacobus Bontius who lived on the island of Java wrote of wild apes there called “Ourang Outang,” meaning “man of the forest.” The picture that accompanied his description looks like a woman with a lion’s mane.
Bontius’s name for these creatures stuck. In fact, seventeenth century naturalists came to use “Orang-Outang” to refer to any ape, even a chimpanzee. Over the next two centuries, some dead orang-outangs made their way to the anatomical labs of Europe, and a few live ones made it to zoos. They were juveniles, often taken from their mothers, and they didn’t last long in captivity before dying of diseases. Baby orangutans, chimpanzees, and gorillas all looked a lot more alike than mature individuals, and so they all continued to be called orang-outangs.
Not only were they similar to each other, but they were disconcertingly similar to humans. Some naturalists responded to this realization by placing apes just below humans on the Great Chain of Being, a kind of divine ladder that separated species on different rungs from lower to higher forms. Linnaeus, on the other hand, put orangutans and other apes in the same genus as humans. Rousseau even wondered if they were “a race of genuine wild men.” Even more scandalously, Lamarck proposed that orangutans were the ancestors of humans.
Upstanding Victorian scientists in Britain were scandalized by such revolutionary talk. The geologist Charles Lyell mocked Lamarck for the idea that an orangutan could evolve to the point that it attained “the dignity of man.”
Darwin, on the other hand, warmed to the idea of evolution after his return to England in 1837. And he wasn’t about to declare humans beyond its influence. To understand the link, if any, between humans and orangutans, he decided to investigate it for himself. Hence he climbed into a cage with a young female orangutan named Jenny.
In his letter to his sister, Darwin described his first encounter:
the keeper showed her an apple, but would not give it her, whereupon she threw herself on her back, kicked & cried, precisely like a naughty child.— She then looked very sulky & after two or three fits of pashion, the keeper said, “Jenny if you will stop bawling & be a good girl, I will give you the apple.— She certainly understood every word of this, &, though like a child, she had great work to stop whining, she at last succeeded, & then got the apple, with which she jumped into an arm chair & began eating it, with the most contented countenance imaginable.
Van Wyhe and Kjaergaard have now found two folded sheets of cream-colored paper in the collection of Darwin’s documents archived at Cambridge University. Each is marked “Man,” which was how Darwin labeled his notes on human evolution. (You can see the original sheets here, although deciphering Darwin’s chicken scratch is best left to experts like Van Wyhe.)
Darwin wrote these particular notes in September 1838, when he returned to the zoo to spend more time with Jenny and another orangutan named Tommy. It’s fascinating to look at what details jumped out at Darwin, and to try to infer why they matter so much to him at that point in his scientific thinking.
Sex was on his mind, for one thing. He jotted down that zookeepers told him that monkeys could “know women perfectly.” Orangutans, he wrote, “seem to have trusted sight & not smell for knowing sexual difference.” Jenny, he added, was “particularly fond of watching boys bathe.”
To these observations he added, “How wonderful. early men have seen women naked, must then smell & afterwards association by sight–this is most curious as proof of origin of mankind.”
Darwin also looked for emotional displays in Jenny’s face, judging her to be “decidedly jealous. She would make her jealousy known by showing her teeth and “making peevish noise.” If she saw others getting attention, he wrote, she “shook the cage & knocked her head against door because she could not get out. –Jealous of attention to other.”
To Darwin, this was not anthropomorphism–imposing human experiences on non-humans. Instead, he was convinced that orangutans and humans had similar emotions because they shared a common ancestor.
Humans are also notable for how we make and use tools. And so Darwin paid close attention to how Jenny played with objects (the strike-throughs are Darwin’s):
I saw = make swing of straw in whisp =
In play she arrange straw in row, stuffing it through cage, like silly listless child — Played with two sticks, carrying them climbing up with them & trying to reach them —
has is very fond of playing with anything soft, covered itself herself up with two pocket handkerchiefs just like girl with shawl spread them out — considered them as her property would not give them up to me. but the keeper brought them & gave them. followed me & bit me for having taken it away & tried to pick my pocket. —
She is fond of breaking sticks & in overturning things to do this (& she is quite strong) she places tries the lever placing stick in hole & going to end as I saw. — She will take the whip & strike the giraffes, & take a stick & beat the men. — When a dog comes in she will take hold of anything, the keepers say, decidedly from knowing she will be able to hurt more with these than with paw.
Humans are also self-aware, and in recent decades scientists have tested other animals for self-awareness by having them look in mirrors. Darwin had much the same idea in 1838:
Both were astonished beyond measure at looking glass, looked at it every way, sideways, & with most steady surprise.– after some time stuck out lips, like kissing, to glass, & then the two did when they were first put together. — at last put hand behind glass at various distances, looked over it, rubbed front of glass, made faces at it — examined whole glass — put face quite close & pressed it — at last half refused to look at it — startled & seemed almost frightened, & evidently became cross because it could not understand puzzle. — Put body in all kinds of positions when approaching glass to examine it.
We see in these newly revealed notes that the iconic image of Darwin in the orangutan cage is just the tip of a scientific iceberg. Darwin didn’t just jump in a cage, high-five an orangutan, and head back home for afternoon tea. For months, he became something approaching a primatologist. Not only did he observe emotions and behaviors; he also ran experiments, giving orangutans mirrors, tickling them, offering them food. The whole experience left Darwin firmly persuaded that the differences between humans and apes were of degree, not of kind. Humans and orangutans clearly shared a common ancestor, and the evidence endures today in our bodies and behaviors. Such a notion might scandalize Lyell, one of the greatest scientists of the day, but the young Darwin didn’t care.
For all his attacks on Lamarck, Lyell never totally ruled out the possibility of evolution. And after Darwin published The Origin of Species in 1859, Lyell, now in his mid-sixties, came around and accepted it. In 1863, he wrote to Darwin,
When I came to the conclusion that after all Lamarck was going to be shown to be right, and that we must go the whole orang I re-read his book, and remembering when it was written, I felt I had done him injustice.
Van Wyhe and Kjaergaard borrowed Lyell’s phrase for the title of their new paper, “Going the Whole Orang.” It’s open access, so you can read the whole thing for yourself here. It’s worth your time.