Theories

Bigfoot is one of the more famous creatures in cryptozoology. Cryptozoologist John Willison Green has postulated that Bigfoot is a worldwide phenomenon (Green 1978:16).
Indian Native tribes in the Northwest note the appearance of large creatures they call Sasquatch. Such creatures were said to exist on Vancouver Island and near Harrison Lake.
The earliest unambiguous reports of gigantic apelike creatures in the Pacific Northwest date from 1924, after a series of alleged encounters at a location in Washington later dubbed Ape Canyon, as related in The Oregonian. Reports the pro-Bigfoot authors claim are similar appear in the mainstream press dating back at least to the 1860s. The phenomenon attained widespread notoriety in 1958 when enormous footprints were reported in Humboldt County, California by roadworkers; the tracks pictured in the media inspired the familiar name "Bigfoot".
Mainstream scientists generally dismiss the phenomena due to a lack of representative specimens. They attribute the numerous sightings to folklore, mythology, hoaxes, and the misidentification of common animals.
Ecologist Robert Michael Pyle argues that most cultures have humanlike giants in their folk history. "We have this need for some larger-than-life creature."

Skeptics
Mainstream scientists and academics overwhelmingly "discount the existence of Bigfoot because the evidence supporting belief in the survival of a prehistoric, bipedal, apelike creature of such dimensions is scant". In addition to the lack of evidence, they cite the fact that while Bigfoot is alleged to live in regions unusual for a large, nonhuman primate, i.e., temperate latitudes in the northern hemisphere, all other recognized nonhuman apes are found in the tropics, Africa, continental Asia or nearby islands. The great apes have never been found in the fossil record in the Americas, and no Bigfoot bones or bodies have been found.
Moreover, the issue is so muddied with dubious claims and outright hoaxes that many scientists do not give the subject serious attention. Napier wrote that the mainstream scientific community's indifference stems primarily from "insufficient evidence ... it is hardly surprising that scientists prefer to investigate the probable rather than beat their heads against the wall of the faintly possible" (Napier, 15). Anthropologist David Daegling echoed this idea, citing a "remarkably limited amount of Sasquatch data that are amenable to scientific scrutiny." (Daegling, 61) He advises that mainstream skeptics take a proactive position "to offer an alternative explanation. We have to explain why we see Bigfoot when there is no such animal" (ibid 20). Indeed, many scientists insist that the breeding population of such an animal would be so large that it would account for many more purported sightings than currently occur, making the existence of such an animal an almost certain impossibility.
On May 24, 2006 Maria Goodavage wrote an article in USA Today titled, "Bigfoot Merely Amuses Most Scientists", in which she quotes Washington State zoologist John Crane, "There is no such thing as Bigfoot. No data other than material that's clearly been fabricated has ever been presented."

Proponents

Bigfoot sculpture at the Socrates Sculpture Park, Long Island City, Queens, NY.
Although most scientists find current evidence of Bigfoot unpersuasive, a number of prominent experts have offered sympathetic opinions on the subject. In a 2002 interview on National Public Radio, Jane Goodall first publicly expressed her views on Bigfoot, by remarking, "Well now, you'll be amazed when I tell you that I'm sure that they exist... I've talked to so many Native Americans who all describe the same sounds, two who have seen them. I've probably got about, oh, thirty books that have come from different parts of the world, from China from, from all over the place...." Several other prominent scientists have also expressed at least a guarded interest in Sasquatch reports, including George Schaller, Russell Mittermeier, Daris Swindler and Esteban Sarmiento.
Prominent anthropologist Carleton S. Coon's posthumously published essay Why the Sasquatch Must Exist states, "Even before I read John Green's book Sasquatch: The Apes Among Us, first published in 1978, I accepted Sasquatch's existence" (Markotic and Krantz, 46). Coon examines the question from several angles, stating that he is confident only in ruling out a relict Neanderthal population as a viable candidate for Sasquatch reports.
As previously noted, Napier generally argued against Bigfoot's existence, but added that some "soft evidence" (i.e., eyewitness accounts, footprints, hair and droppings) is compelling enough that he advises against "dismissing its reality out of hand" (Napier, 197).
Krantz and others have argued that a double standard is applied to Sasquatch studies by many academics: whenever there is a claim or evidence of Sasquatch's existence, enormous scrutiny is applied, as well as it should be. Yet when individuals claim to have hoaxed Bigfoot evidence, the claims are frequently accepted without corroborative evidence.
In 2004, Henry Gee, editor of the prestigious Nature, argued that creatures like Bigfoot deserved further study, writing, "The discovery that Homo floresiensis survived until so very recently, in geological terms, makes it more likely that stories of other mythical, human-like creatures such as Yetis are founded on grains of truth ... Now, cryptozoology, the study of such fabulous creatures, can come in from the cold."

Hoaxes
There are times when a Bigfoot sighting or footprint is a hoax. Author Jerome Clark argues that the "Jacko" affair, involving an 1884 newspaper report of an apelike creature captured in British Columbia (details below), was a hoax. Citing research by John Green, who found that several contemporary British Columbia newspapers regarded the alleged capture as very dubious, Clark notes that the New Westminster, British Columbia Mainland Guardian wrote, "Absurdity is written on the face of it" (Clark, 195).
In the past decade or so, the style of Bigfoot hoaxes winning wider news attention were false claims of hoaxing famous pieces of evidence such as the "Patterson Footage" or the Jerry Crew tracks from Bluff Creek.
In 1958 bulldozer operator Jerry Crew took to a newspaper office a cast of one of the enormous footprints he and other workers had been seeing at an isolated work site in Bluff Creek, California. The story and photo garnered international attention through being picked up by the Associated Press (Krantz, 5). Crew was overseen by Wilbur L. Wallace, brother of Raymond L. Wallace. Years after the track casts were made, Ray Wallace got involved in Bigfoot "research" and made various outlandish claims. He was poorly regarded by many who took the subject seriously. Napier wrote, "I do not feel impressed with Mr Wallace's story" regarding having over 15,000 feet of film showing Bigfoot (Napier, 89).
Shortly after Wallace's death, his children called him the "father of Bigfoot". They claimed Ray faked the tracks seen by Jerry Crew in 1958. There were some wooden track makers among Ray's inherited belongings which the family said were used to make the 1958 tracks. At the height of the publicity, the Wallace family sold the story rights to a Hollywood filmmaker. The film, set to star actor Judge Reinhold, was never produced.
Canadian newspaperman John Green argues that Ray never claimed to have made the Bluff Creek tracks and was not present in the Bluff Creek area when the Crew cast was obtained. Wallace had road-building contracts in various parts of the north-west and was usually not around in Bluff Creek. Years after the fact, Wallace attempted to capitalize on the interest in various ways. He tried to sell various items from a roadside shop, including Bigfoot footprint replicas, which he made behind his shop using a pair of wooden track stompers.