I was watching some old documentaries on YouTube and a particular one on Bigfoot made some points I hadn’t considered in my conclusion that it was just a mix of myth and hoax.
Don’t get me wrong, I haven’t become a believer, but I now don’t feel that there’s enough evidence to solidly disbelieve either. (Luckily, I don’t really have an emotional connection to either outcome, and that ambivalence makes it easy to sit on the fence.)
So, why was I so certain that Bigfoot didn’t exist before? Mostly because I had the following strong arguments which grouped Bigfoot in with other things that everyone agrees to be fake:
First (and most convincingly), now that everyone has a cameraphone in their pocket and an entire generation is obsessed with getting attention using it, we should be seeing a lot more evidence. Evidence for real phenomena doesn’t stay flat as the number of people with the will and means to gather it grows exponentially.
The BBC had a whole series, Nature’s Weirdest Events, built entirely around this idea and the fact that, with the massive number of people carrying cameras now, even very rare occurrences are getting conclusive recordings made.
Second, in 2017, they finally did DNA analysis on purported Yeti remnants (fur samples caught on vegetation in valleys, scalps kept as relics, etc.) and every single one was conclusively determined to not be from an unknown primate. Some were potentially from an unknown type of bear, but the only conclusively positive result that was surprising was that, judging by the fur samples, the Himalayan goral has a larger range than we thought.
Third, oral histories (in any culture) tend to blend myth and reality in ways that mislead those who try to extract reality from them without being experts, and Bigfoot believers invariably brush this under the rug.
Fourth, it’s very rare for large animals to remain undiscovered. The countless new species we continue to discover tend to be insects, small reptiles and amphibians, plants, and fungi. When we do discover new large species, thet tend to live in the deep ocean, which has been compared to the moon in remoteness.
Fifth, it’s suspicious that humans would have legends of such cryptids on every continent with aboriginal populations, including Australia, when we only have such a large range because we’re a tropical species who developed fire and clothing.
Finally, Bigfoot believers tend to set up a false dichotomy that, with all this evidence, it must either be true or some grand conspiracy to commit a hoax. However, we humans have a history of cognitive biases producing odd results.
It doesn’t have to be a global conspiracy to engage in a hoax if our neurobiology is inherently biased toward developing the concept of “wild men of the wilderness” in the same way that it’s inherently biased toward inventing gods to explain nature.
When people see something they’re not certain about, they tend to fill in the details based on whatever cultural zeitgeist is floating around in their heads. One of the books I’ve read (probably Carl Sagan’s The Demon-Haunted World) went into detail on how the post-World War 2 UFO craze caused a rapid shift in interpretations of existing events like sleep paralysis.
UPDATE: Likewise, as demonstrated by LEMMiNO’s Bygone Visions of Cosmic Neighbors, even scientists tend to fight hard against giving up preconceptions that we want to be true, such as the idea that intelligent life exists on planets in our solar system other than Earth.
It also doesn’t help that, often, the lack of increased evidence in response to increased technology is justified by the special pleading that ape-like cryptids are smart enough to have learned to be more elusive in step with our developing technology.
So, with all that strongly leaning away from Bigfoot being real, what did the documentary say that cast it back into doubt?
First, it pointed out two things that I had never seen mentioned in any other documentary, and which hadn’t occurred to me before:
- It’s rare to find animals remains in the wild, because they tend to retreat to die, and, when it’s not dead livestock in the middle of a wide-open pasture (with no cover and possibly a guard donkey or llama), scavengers are very efficient.
- Animals like Bigfoot and the Yeti are said to live in areas which are still rugged and sparsely-populated to this day.
As the anthropologist they interviewed said, there are at least 100 bears for every Bigfoot and he’s never found a bear that died a natural death, just lying there in the wild.
That ties in with an important detail I already did know: Some animals are very shy. Heck, even primates we know about can present supporting evidence. Western scientists didn’t acquire specimens of the mountain gorilla and bonobo until 1902 and the 1920s, respectively.
According to one believer in Bigfoot whose videos I watch because he applies enough skeptical argumentation to make them interesting and entertaining whether or not you consider them credible, we have enough trouble with known primates:
- People who haven’t worked with wild chimpanzees and other great apes underestimate how aware they are of automatic cameras that have been placed in their habitats. When they’re caught on camera, it’s because they choose to be.
- The reason it took so long to learn what we know about the Bili/Bondo apes (a population of chimpanzees) is that, to avoid bush-meat hunters, they don’t allow themselves to be seen within 20km of a road… and these are animals we know to exist. 
Beyond that, from observations of other shy species, it’s perfectly plausible to conclude that there exist species so shy that they are likely to go extinct from competition for habitat before we ever encounter them and it’s plausible that Europeans, having a more industrialized and less in-tune-with nature lifestyle, produce a larger “radius of deterrence” compared to aboriginal peoples.
There were a couple of other points made in the documentary regarding pre-Columbian evidence (some native carvings that seem too consistently ape-like and a claim that Leif Erikson encountered a “forest spirit” that doesn’t fit the description of of a Native American), but I had to discard them since I couldn’t find any solid online corroboration and I don’t care enough to go poking through offline sources.
Third Option: Maybe Bigfoot once existed but doesn’t now
Everybody seems to be so caught up in taking sides that I’ve never seen anyone address this possibility. Maybe all the 20th century stuff is hoaxes and wishful thinking, but there really is something to the native myths.
Difficulty in testing it aside, it’s certainly a reasonable hypothesis. Tribal history doesn’t really care about precisely recording how long ago the most recent encounter was, and there is strong evidence of pre-industrialized humans driving animals to extinction even when we don’t outright hunt them. (Jared Diamond’s The Third Chimpanzee mentions that, for example.)
All in all, I think you can see why I adopted the more scientist-ish viewpoint of “What do I believe? I believe that the evidence is inconclusive.” (Though, as always, “extraordinary claims require extraordinary evidence”, so I lean toward nonexistence.)
In the end, I think eDNA will probably rule one way or another in the not too distant future. It’s already put the final nail in the coffin for the Loch Ness Monster in any reasonable person’s eyes. (See TREY the Explainer’s previous videos on the Loch Ness Monster for my reasons to say “final nail”.)