With regards to DNA evidence, you don't even need anything you would recognize as physical evidence (such as scat or hair) anymore. At my company we sometimes use Environmental DNA (colloquially known as eDNA) to look for certain species (usually amphibians for us, but it can be used for basically any living organism). It's not that expensive anymore either, the bigfoot hunters that can afford a bloody TV show could very well do eDNA sampling of any tracks they find or even air, soil or water at their "hotspots" to see if an unknown hominid pops up. From the wikipedia article:
Environmental DNA or
eDNA is
DNA that is collected from a variety of environmental samples such as
soil,
seawater,
snow or
air, rather than directly sampled from an individual
organism. As various organisms interact with the environment, DNA is expelled and accumulates in their surroundings from various sources.
[2] Such eDNA can be
sequenced by
environmental omics to reveal facts about the species that are present in an ecosystem — even microscopic ones not otherwise apparent or detectable.
And it has been used in cryptozoological endeavours! In 2019 a bunch of people led by professor Neil Gemmell at the University of Otago used it to disprove any theory of "Nessie" except for that some sightings might be large eels:
"With over a thousand reported sightings dating back to the 6th century, of all the ideas for what people have seen in the water, one of the more common, and outrageous, is there might be a Jurassic-age reptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness."
"We can't find any evidence of a creature that's remotely related to that in our eDNA sequence data. So, sorry, I don't think the plesiosaur idea holds up based on the data that we have obtained.
The scientists tested other predominant theories of various giant fish: whether it be a giant catfish or a giant sturgeon, an eel, or even a shark such as a Greenland shark.
"So there's no shark DNA in Loch Ness based on our sampling. There is also no catfish DNA in Loch Ness based on our sampling. We can't find any evidence of sturgeon either," Professor Gemmell said.
Gemmell et al found a very significant amount of eel DNA in Loch Ness. Image credit: University of Otago.
The remaining theory that the team cannot refute based on the eDNA data obtained is that what people are seeing is a very large eel.
"There is a very significant amount of eel DNA," Professor Gemmell said.
It
has also been used by the bigfoot hunters, but I can't find that anyone published any actual data, instead you just get videos like this one
External Quote:
where they discuss the results they get as follows, regarding the first sample:
External Quote:
Dr. Mireya Mayor: "First up are the eDNA results from the most recent samples we collected at those odd-looking nests in Norhtern California. We got small hits of Sumatran Orang DNA"
Russel Acord: "Wow!"
Bryce Johnson: "Wait. Are you saying orang as in orangutan?"
Mayor: "Exactly, which are just as surprising as our chimp findings. However, I will qualify it by saying that the hits were not nearly as many as we did with the chimpanzee DNA initially. I do think that it is interesting that it would be orangutan, because I've read about Gigantopithecus which orangs are a direct descendant of."
Now, even though she for some reason chooses to chase bigfoots on TV, Dr. Mayor is a primatologist with a PhD and much better credentials than I have, but characterizing modern orangutans as the direct descendants of G
igantopithecus is absolutely not a mainstream position (the mainstream position is that it is a sister clade to
Pongo that diverged from a common ancestor about 10-12 Mya (see
Welker et al 2019).
Also, saying that there were "few hits" without any data or other context than the earlier find of presumed chimpanzee DNA at another site gives us absolutely nothing to compare it to, but given the absolutely improbable results of an orangutan, I find it likely to be erronous. eDNA is not exact and understanding what it is you actually found is impossible when you won't publish your findings.
Not to mention, you said you found chimp dna earlier? So, is bigfoot related to chimps or orangutans? Are you saying there are
two different species of unknown large hominids, from
two different evolutionary lines with no other known representation of extant species or even anything in the fossil records from
the entire continent running around in North America?
The second sample discussed in the video comes back as human (no big surprise there, even though they refuse to believe it because Acord who purportedly saw and chased "the thing" the sample is supposed to come from says: "I can't think of any human on the planet that could have done what that thing was doing".
To their credit, they don't discuss it further than that in the video, refraining from claims of it being a close human relative.
The third sample is a doozy (from 3:43 in the movie):
External Quote:
text on screen: THE LAST REMAINING TEST RESULTS HAVE COME IN.
A HAIR FOUND NEAR POSSIBLE NESTS IN NORTHERN CALIFORNIA HAS YIELDED UNEXPECTED RESULTS.
[some more exposition and talk cut here]
Johnson: "Well, the lab results are back and they're somewhat shocking. So, although the DNA was kind of degraded they were able to make a determination of species. And get this: that species is wolf!"
Acord: "Oh, wow!"
Mayor: "What?"
Johnson: "Listen, that's not even the amazing part. They were actually able to determine that it was a subspecies of wolf known as the Alexander Archipelago wolf, which only lives in one place: south-eastern Alaska."
Everyone else: "Wow!"
Mayor: "Huh."
Johnson: "It begs the question, y'know, how did that hair get from Alaska to Northern California? Mireya, do we know anything about these animals, do they migrate?"
Mayor: "They don't. And I know this animal. There's only a few hundreds of these left in the wild, so if this test result is accurate and that's the animal that we're talking about there is zero chance that it would make its way to California."
Okay, so, ignoring that the Alexander Archipelago wolf,
Canis lupus ligoni is, together with the British Columbia wolf,
C. lupus columbianus considered to be subsumed into the Vancouver Island wolf,
C. lupus crassodon due to them having a complete overlap in genetic diversity (see
Weckworth et al 2011) which already casts doubt on the analysis being able to distinguish between those subspecices, do wolves migrate?
Now, to be fair, sure, wolfs do not migrate seasonally or otherwise, but that doesn't mean that they can't move over huge distances, which they often do. That's how that species complex has become so widespread in the first place. The wolf population of middle and south Sweden and Norway is genetically dependent on wolves from Finland and Russia (wolves are not allowed to establish territories in Northern Sweden due to conflicts with traditional Sami reindeer herding) walking there, a trek of at least 800 km, and often much more. The distance from the southern border of the Alaskan panhandle to California's northern border is roughly 1700 km, which sure, it's twice the minimum distance a Russian wolf would have to walk to get to a "safe" area in Sweden, but it is not an unsurmountable distance for a wolf either, like Slavc here, who walked over 2000 km in 2011-2012:
Slavc is a wolf. In 2011, he began an epic 2,000 kilometre migration across Europe from Slovenia to Italy via the Austrian Alps. Several months earlier, he had been fitted with a collar that allowed his movements to be tracked in incredible detail.
Also, if we use the actual, most up-to-date taxonomy and thus define the
C. lupus crassodon subspecies as containing the other two subspecies, the distance for walking to California shrinks to the same 800 km as in the case of Sweden.
Though in this case, my assumption is that the more likely and prosaic explanation is simply that the test, because the DNA was degraded, were unable to differentiate between the different subspecies of wolf that actually live in the area*—
C. lupus occidentalis—and
C. lupus crassodon. And the fact that the lab according to Johnson labeled the hair as
C. lupus ligoni doesn't give me much confidence about them being that up-to-date visavi the latest phylogenetic studies of wolves.
I also found a crowdfunding page Jeff Meldrum put up in 2017 to do some eDNA study on "sasquatch ground nesting sites" that failed to reach its target:
Source: https://www.indiegogo.com/projects/sasquatch-nests-edna-study#/
So they seem to be aware, and to some extent actually using the technology, but they do not seem to share any data and none of their "amazing findings" that I could find have amounted to anything, suggesting that they are deliberately hyping up poor results for ratings or misunderstanding the actual data they find.
*here I at first made an embarassing mistake, further described in my post below. Above it is edited. Also: I'd argue that the coyote is a wolf species, but if they were bold enough to claim a subspecies of grey wolf, I hope that they really know how to differentiate a grey wolf from a coyote.