There are a lot of parallels between ghost hunting and bigfoot hunting. These include the high probability of misperception and misidentification, the lack of proper analysis of "evidence", people with no formal credentials calling themselves "experts", cognitive bias, fraud and overall poor investigative techniques.
Like ghost hunting, a lot of people talk in absolutes about Bigfoot, meaning they assert things as facts that have little or no evidence to back them up. For example, some enthusiasts claim that Bigfoot is either a descendant of, or close relative of the extinct Gigantopithecus. The late anthropologist Grover Krantz made this speculation. The problem is, there is no evidence that one ever made it to this continent. Another issue is, as far as I know, nobody has proven that Gigantopithecus was bipedal, walking upright. The supposition came from the size of jaw fragments and speculation how the skull would fit on the neck. But many researchers assert there is more evidence it was a quadruped, based on its massive size.
Another example is that we're often told that Bigfoot is a nocturnal creature. This is likely due to more alleged encounters occuring at night. But for me, this simply increases the probability of misidentification. The human eye is not designed well for night vision. We don't see colors as well in the dark and our peripheral vision, which detects motion but does not register details well, often misinterprets what is seen out of the corner of the eye. The brain fills in missing data, and add suggestibility and fear, and the result becomes a bigfoot. Finally, we are also told these creatures communicate by knocking wood. Maybe they do, but there are also other possible (and more likely) sources of these sounds.
There are similar credibility issues with the claims from eyewitnesses who see a bigfoot and those who see ghosts. The same environmental or physiological factors that can impede one's perception in an allegedly haunted location can affect someone out in the middle of the woods. I already mentioned poor visibility at night. There are studies which suggest infrasound can impact our physiology and induce seemingly paranormal experiences, including unexplainable anxiety and visual disturbances. There are natural causes of infrasound like running water in rivers and waterfalls. Thunderstorms can produce infrasound, as can tectonic activity.
There are reports of campers who wake up in the middle of the night to find a bigfoot lurking in their camp. Besides misidentification, another common phenomenon to consider is hypnagogic hallucinations, which occur in a semi-dream state upon falling asleep or waking up. Fatigue, stress, change in sleeping habit/patterns are known factors that can cause one to experience this disorder, and are not uncommon on a camping/hiking trip. The experience seems very real - subjects report seeing, feeling, hearing, and smelling things in this state that are not real. Why would the brain pick a bigfoot and not a ghost? The surrounding environment (woods) likely plays on the subconscious and plants the suggestion, even if the camper doesn't consciously believe in the creature.
Eyewitness testimony is highly flawed, especially when fear is involved. It is simply not reliable. When doing research for a story, another writer friend learned that the NYPD uses regular decoys for their line-ups and 20% of the time, a decoy is mistakenly IDed by a victim. As mentioned before, when we don't have sufficient data, our brains take over and "fill in" details for us. Our perception is skewed. So when we are startled by something happening quickly out of the corner of our eye, what seems like a 7 foot tall creature in reality could be much smaller and more mundane. Not long ago, I watched a psychological study profiled on a TV show about the Loch Ness Monster. A group of people on one shore were told about the study. A log was launched and the group was asked to sketch what they saw. They all drew a straight log. Then the researchers interviewed people on the other side of the shore - who were not informed of the experiment - to sketch what they saw. Miraculously, the straight log suddenly grew an angular neck and head in some of these drawings. It's not because the people were being dishonest, but because their expectations filled in the details. (See, not all the TV shows are bad, haha.)
The evidence suggesting the existence of the creature remains elusive and controversial, at best. Every picture and video of the creature seems to be blurry and therefore inconclusive. Without visual confirmation, any audio evidence is useless. But the cryptozoologists do have a couple of advantages over ghost hunters. First, they have a more tangible idea of what it is they are looking for: presumably, a bipedal primate. (For today, I am not entertaining any notion it's a supernatural being.) Second, they can examine physical evidence like hair, prints, and scat allegedly left by the animal. But evidence is another area where we encounter credibility issues.
One of the main criticisms about ghost hunters is that many do not understand how to properly use their equipment, analyze so called "evidence", recognize what factors in the environment can affect the the witnesses (and equipment), or fail to put controls and procedures in place to reduce false positives. The same can be said of many bigfoot hunters. Many bigfoot hunters I have talked to have no formal training or experience in biology, anthropology or other relevant sciences, which would be usefull on a bigfoot hunt. Personally, I took biology in college and even have a credential that says I can teach it. But that does not make me a biologist nor qualified to lend any "expertise" if I came across any supposed evidence. It would be an insult to those who major in these sciences, have completed field experience, and earned their degree.
Many boast their experience as hunters make them qualified as any field biologists. However, many promising bigfoot prints found by hunters were later identified by pesky science people to be either bear prints or even bobcat prints, where as the animal walked, the posterior paw stepped into the print left by the anterior paw, making a elongated footprint shape. Weather can quickly distort the size and shape of a print left by an animal, so that an inexperienced observer could easily misidentify it. Most bigfoot hunters are not qualified to distinguish between static print left by a hoaxer, or a dynamic print left by a living animal. Many hair or scat samples have been rendered useless for DNA testing by mishandling and contamination by inexperienced enthusiasts. Many are simply not familiar with the habits and sounds of other animals inhabiting the woods. When one is looking for a bigfoot, any unfamiliar sound can be attributed to one. Furthermore, it is impossible to place controls for audio in the woods. Without credible corresponding video, we have no way of knowing whether you recorded a bigfoot whistling or an aggravated thrush. Again, without credible corresponding video, if rocks are being thrown at you or your camp, we have no idea they are being tossed by Bigfoot or a human screwing with you.
Which brings us to fraud. Let's face it: it is far easier to fake and film a bigfoot sighting than to actually find a bigfoot. The internet and YouTube is full of bogus bigfoot footage. There have been frauds saying they have killed or captured the creatures. Yet, in this day of everyone and their grandma carrying cell phones with built-in cameras, somehow nobody ever gets it on video. I personally support the "No Kill" approach to Bigfoot. First, capture will satisfy science. Second, because sightings are likely due to misidentification or hoaxes, a human is likely to get killed before a bigfoot. Some places even have made the bigfoot a protected species. I am all for this for the same reason: to prevent somebody getting shot by an overzealous bigfoot hunter. Just last week, a man trying to pull off a bigfoot hoax got himself killed when a car hit him.
It doesn't help when some of the TV shows on Bigfoot portray shoddy investigative techniques. Announcing to a community that you will be in the immediate area to film a bigfoot hunt really sets one up for problems, including hoaxers or just curious looky-loos. Running around in the dark after every odd sound is ridiculous. While eye-witness accounts are obviously a starting point, relying on them as evidence without looking for any other explanation is not valid research. Just like ghost hunting shows, false positives are also presented as evidence, because that's what keeps viewers tuned in.
At the beginning, I admitted that I lean more toward the possibility of Bigfoot's existence. Part of this is my own preference. I want to believe the accounts I heard. I also wonder about some of the sightings reported in broad daylight by forest rangers, experienced life-long hunters and Native Americans. Are they all misidentification? Before the bigfoot craze in the 1960's, there were reports from pioneers and Native Americans of such creatures dating back hundreds of years, not just in the Pacific Northwest, but on the East Coast and Canada. Is there some truth to these stories? Since everyone else gets to make assumptions, I'd like to throw in a couple. What if we are dealing with something closer to us than apes? Recently, researchers found evidence supporting Neanderthals were capable of language. Perhaps these creatures are capable of communication, and possess the intelligence to stay the hell away from us. Maybe they even bury their dead. What if the reports of some tribes are true and these creatures are cannibals? After all, there are still tribes today that practice cannibalism. If they have their late Uncle Bob over for a barbeque, this may also explain why bodies are not found.
When it comes to paranormal research, I believe it is our purpose as paranormal investigators to find valid answers - paranormal or not - for claims. We need to ask, "What can cause this experience?" and then strive to find every rational explanation first. Otherwise, we might as well save time and money and just sit around a big campfire and tell each other ghost stories. We will never find the answers we seek if we cling to false evidence and jump to conclusions to suit an agenda to prove ghosts exist. The same holds true for Bigfoot hunting. As much as I hope Bigfoot is wandering about in dense forests, I value the truth - and obtaining it through valid research - even more.