Climbing the Tree of Knowledge

Part I by Dr. Donald Perry
Dr. Perry welcomes your comments and questions. Please email him at canopy evolution at

In 1973 I took a class in tropical biology where I was astounded to learn that while most rain forest species lived in the tropical rain forest canopy, it had yet to be explored. Without a doubt, many species new to science resided within that realm, not to mention the amazing natural history hidden there. But this treasure chest of biological diversity had remained unexplored for good reason. The most-prolific canopy communities are found living on top of broad limbs within the crowns of emergent trees — rain forest giants. Their trunks can be up to twenty feet in diameter (including the buttresses) and the first limbs are often over ninety feet above ground. While humanity’s amazing exploratory efforts had recently allowed us to walk on the moon’s sterile surface, there was still no effective method for exploring earth’s “arboreal continent” – home of the most-complex communities of life in the known universe.

2 tree climbers darkly sillhouetted against sky and top of tree

Andy Starrett, my professor at California State University Northridge, stared at me with an incredulous expression as I told him my crude plan to climb emergent trees. He had stretched mist-nets between the buttressed toes of these trees to capture bats for research, an extremely important group that pollinates and disperses many rain forest trees and plants. He didn’t try to dissuade me from this challenging biological adventure, perhaps because heights were in his blood too; his father had owned the construction company that built the Empire State building.

My first trip to Costa Rica was in June 1974, a time when that country still had vast expanses of jungle. My book, Life Above the Jungle Floor, is the first chronicle of rain-forest canopy life and it was the model for the feature film Medicine Man.

My simple plan was to throw a weight tied to a fishing line over a high tree limb, tie a heavier cord to the fishing line and pull that up, then pull a climbing rope into position with the heavier cord. I used mountaineering equipment to climb the rope. This allowed me to avoid the trunk where a dense tangle of leaves and vines concealed deadly tree vipers, ants and wasps to name a few. Of course I couldn’t escape every risk; support branches can be rotten. Since I was the only climber in Costa Rica at the time, I would be on my own if I fell or got stuck high in a tree.

It proved to be impossible to reach high limbs with the weighted fishing line so I searched for a large tree with a small neighbor. A beautiful emergent, Dipteryx panamensis, was in full bloom next to a smaller tree near the research station at Finca La Selva.

It was fairly easy climbing into the smaller tree and by noon I had succeeded in pulling the rope over the Dipteryx’s lowest branch. The rope, however, had become tangled in the smaller tree, and in order to dislodge it, I decided to jump and swing under the large limb. This proved to be a thrill for which I was ill-prepared. I stepped off the limb and dropped into a frightening near freefall. With what seemed like tremendous speed, I began to swing on a huge arc. The ride was similar to a roller-coaster as I slowed to a brief stop at the top of the far side, followed by a stomach-wrenching drop as I retraced the swing, now backwards.

The following year I returned with a crossbow. It allowed me to shoot the fishing line over limbs 150 feet high. This simple tool, along with an assortment of mountain-climbing gear, was the first effective tall-tree climbing method. Beginning in 1976 I used this method to take numerous scientists and several La Selva tourists on tree-climbing, canopy tours. I published the method in the journal Biotropica in 1978, and ever since the method has been used by researchers and explorers worldwide. Especially satisfying is that this method was critical for the investigation of tall trees like the coastal redwoods of California, my home state.

While working on my Ph.D. at UCLA in 1979, I developed the first canopy zipline with the help of John Williams, This rope system allowed both lateral and vertical travel, so I was able to investigate a volume of rain forest. The story was published in Smithsonian, magazine (June 1980 and in, Scientific American 1984) published the story featuring me hanging from my system on the front cover.

At the end of the Smithsonian Altered States article I hinted at the future of my research — the role played by climbing in the evolution of human intelligence. Those were exciting times. I wrote, “I felt I could almost be Man’s arboreal ancestor.” While climbing, I marveled that the human nervous system was especially well-designed for canopy work. A few times, I had the odd sensation of regressing deeply into the murky past, almost becoming the human ancestor– as in the film. I would then find myself on a live virtual tour, clambering along the same arboreal trails taken by our ancestors on their evolutionary path to humanness. After several decades of study, the seed of that rumination has grown into a book I have copyrighted but have not yet published called The Descent. It is the first comprehensive theory of human brain evolution.

Shortly after the Smithsonian Ramapithecus” article, I was cornered by a student anthropologist at a cocktail party. “Man’s arboreal ancestor”, he began to lecture, “was at the time, this belief was held by nearly the entire anthropological community. Parroting current views, he explained how scientists were certain that upright walking, hunting with weapons and self awareness evolved after our ancestors quit climbing trees. It was thought that our ancestors had abandoned their arboreal lifestyle at least fifteen million years ago. In other words, there was no “arboreal human ancestor”. What this student and many others didn’t know was that they had been sold a myth.

looking up at group of 5 tree climbers in the branches

The Ramapithecus myth grew from a stubborn theoretical bias for life on savannas. Because the thought of being recently related to a silly grinning primate with hands for feet has always been unacceptable, fossil hunters knew what they had to find: a more-sophisticated, less-apelike ancestor. So for the last century and a half, every shard of bone has been forced into a puzzle it doesn’t fit. The puzzle’s image is the one of pure conjecture based on Darwin’s idea of our origins. So when a few teeth and bits of jaw were discovered, the artwork depicted an “ape person” walking upright on a savanna with no forest in sight. The imagined being was holding a weapon, but it was too crude to be used for protection against the super-sized predators of the time. That could not have been our ancestor; it would have been gobbled up into extinction if it set foot on a savanna.

The Ramapithecus myth vanished with the uncovering of a more-complete set of the animal’s bones. Ramapithecus turned out to be something very much like an orangutan.

Around the time of Ramapithecus’ fall, anthropologists took another blow. They remained steadfast in their belief that we were not closely related to chimps and that upright walking originated around 15 to 20 million years ago — after we abandoned the trees. Meanwhile, scientists outside of anthropology, molecular biologists, began to experiment with tests that convincingly established chimpanzees as our closest relative. Somewhat unnoticed is that this finding brought the climbing era of human evolution to just six million years ago, over fifty percent closer to the present. A climbing past was pushing its way up the timeline.

The sixties, seventies and eighties affected a perfect storm with swell after swell sinking unreasonable anthropological theories. A prime example was the famous discovery of Lucy. With the death of Ramapithecus she had become the flag bearer; the new, first human ancestor thought to have favored full-time life at the ground. But as with the feeble weapon drawn in Ramapithecus’ hand, there was no empirical evidence that Lucy had abandoned tree climbing. In fact the fossil record revealed her ape-like fingers; fingers that must have been used for climbing!

Prominent anthropologists focused on Lucy’s bipedalism, hoping she could further distance us from tree-climbing animals. She lived 3 million years ago, and while her bipedalism demonstrates that she could leave the trees, her fingers tell us she could also climb very well. (It is now known that upright walking originated while we were devoted tree climbers).

The search for the origins of upright walking overshadowed an extremely important point. Just as now, upright walking in no way prevented climbing. Nevertheless, an article in Scientific American quoted a leading stating that since Lucy had legs like humans, her legs would have broken if she had climbed. The statement reveals a deep vein of bias against climbing that has chronically hindered the anthropological community’s ability to accurately interpret the data.

Anthropologists justified this position with the anti-evolutionary notion that climbing fingers were not used for climbing. They labeled climbing fingers “evolutionary baggage”. When mole-like claws are seen on the front feet of an insectivore, it suggests digging. Fins on the arms of a fissiped suggest a  seal-like manner of swimming. So it holds to reason that very strong curved fingers, arms and upper torsos on a bipedal ancestor indicates climbing. Negating what we see— claws are not used for digging, fins are not used for swimming, fingers are not used for climbing — is simply not allowed in real science. The fact is: all adaptations are evolutionary baggage. They are tools of survival that must be unpacked and put to use. Lucy was a seventy-pound defenseless bipedal ape said to be living in a savanna habitat. Given the populations of huge predators at the time, Lucy either put her baggage to work climbing or she became extinct.

With 20/20 hindsight, I could be accused of taking cheap shots at anthropological myths. However, I have been proposing an ancestral human canopy connection for thirty years and while the literature consistently supports my view, there is no support for the anti-climbing views held by anthropologists.

2 tree climbers relaxing at top of climb

I have examined the evidence of numerous ancestors from eight million years ago, up to and including Neandertals, and found a wealth of climbing adaptations and probable behaviors that were either overlooked or categorized as unimportant. Whatever the case, they remain unreported. This unreported climbing data from the fields of morphology, behavior, archeology and paleontology is precisely what led me to originate the first comprehensive theory of human evolution. I call this the “scansorial theory” (climbing theory). My theory answers the single, most-important question of philosophy and science. It shows where human intelligence began and why. It is a story about who we are and where we came from that has never been told.

Copyright © 2014 Donald R. Perry. Published in this Blog with Dr. Perry’s permission. Pictures courtesy of TCC.