The Patterson-Gimlin film

What happened on the sandbar

On October 20, 1967, Roger Patterson and Bob Gimlin were riding beside Bluff Creek, a tributary of the Klamath River in the Six Rivers National Forest, about 25 logging-road miles northwest of Orleans, California. The site given for the film is 41°26′25″N 123°42′7″W, which the FCC's census block lookup returns as Del Norte County, so the county attribution is checkable rather than merely repeated. DOCUMENTED

The two men said that between about 1:15 and 1:40 p.m. they came on a large, dark, hair-covered bipedal figure on a gravel bar, that Patterson dismounted with a 16mm camera and ran toward it while filming, and that the subject walked away, turned its head and upper body to look back over its right shoulder, and went into timber. They were the only witnesses. Greg Long has catalogued inconsistencies between their retellings, and notes that Patterson's size estimates grew in later versions. ALLEGED

The film exists, has been copied at least seven times, and has been studied continuously since 1967. That is a fact about a film.

Patterson shot a second roll of the tracks. They then tracked the subject for either one mile (Daniel Perez) or three (Ivan Sanderson) before losing it in undergrowth, rode three miles to camp for plaster, returned, measured the step length, and cast the best right and left prints. The cast and step figures that circulate are left out here, because the sources carrying them could not be checked.

The camera, the frames, and the 59.5 seconds

The camera was a Cine-Kodak K-100, a 16mm spring-wound model rented on May 13, 1967 from Sheppard's Camera Shop in Yakima, Washington, and loaded with Kodachrome II. The reel holds 76.15 feet of horses and riders, then 23.85 feet of the subject.

In 2010 Bill Munns built a frame-by-frame inventory across several copies, found the older Cibachrome numbering wrong, located a frame 954 on a copy for the first time, and reissued the count. On his VFC-2 system the sequence runs 954 frames, and the famous "frame 352" look-back is frame 354. Most of the older literature, including the 1978 legal settlement, counts 952. DOCUMENTED

That two-frame difference is the whole of the familiar "59.5 seconds." 952 divided by 16 is 59.5. 954 divided by 16 is 59.6. Neither number measures anything. Both are a frame count divided by an assumed frame rate.

Munns and Meldrum's 2013 paper in The Relict Hominoid Inquiry concluded that the film "was not altered or otherwise tampered with for deceptive intent, and that the image quality is sufficient for factual analysis." Three of their findings get repeated in inflated form. They did not measure Kodachrome II at "56 to 65 line pairs per millimeter"; they found three published figures that disagree (56 lines/mm from Popular Photography, 63 lines/mm from Fahrenbach, about 65 line pairs/mm from James K. Beard), measured one fine tree branch in a single 4x5 transparency, and concluded it supported Beard. The "in focus from 10 to 300 feet" claim describes that same transparency, a Kodak enlargement of frame 354, not all 954 frames. About 400 frames are sharp, and they attribute the rest of the blur to television transfers that blend adjacent frames to stretch a 16 to 18 fps source to 30 fps. Their own footnote leaves the lens open: "studies are ongoing to determine which lens was used for the PGF," the candidates being the K-100's standard 25mm f/1.9 Cine Ektar and a 20mm fixed-focus lens. CONTESTED

The paper ran in a journal hosted by Idaho State University's Department of Biological Sciences and edited by Jeff Meldrum, one of its two authors and a full professor in that department. Weigh accordingly.

The same-day reporting, and the objection to it

At about 6:30 p.m. the men reached Al Hodgson's variety store in Willow Creek, roughly 54 road miles from the site. Patterson asked Hodgson to telephone Donald Abbott, hoping he would bring a tracking dog; Abbott declined. Patterson drove on toward Eureka to ship the film, then stopped at the Lower Trinity Ranger Station about 9:00 p.m., where he telephoned the Times-Standard in Eureka. They reached camp near midnight. At 5:00 or 5:30 the next morning, in rain that had already begun, Gimlin rode back and covered the remaining prints with bark, the cardboard boxes Hodgson had given him having been left outside and gone soggy. Forest Service timber management assistant Lyle Laverty said his team passed the site on the 19th or 20th and saw no tracks; he returned Monday the 23rd and made six photographs. Taxidermist Robert Titmus arrived nine days after the event, cast ten successive prints, and plotted the movements on a map.

Grover Krantz argued the same-day call to Abbott was evidence against a hoax by Patterson. It is a reasonable inference and it is disputed. Critics say too much has to fit between 1:15 p.m. at the earliest and Willow Creek at 6:30 p.m. at the latest, and David Daegling wrote: "All of the problems with the timeline disappear if the film is shot a few days or hours beforehand. If that is the case, one has to wonder what other details of this story are wrong." A related objection is that Kodachrome II could be developed only by a lab with a machine costing upward of $60,000, that the few West Coast labs known to have one did not develop over weekends, and that Al DeAtley, Patterson's brother-in-law, says he cannot remember where he took the film or where he collected it. Laverty's report of clean ground on the 19th or 20th cuts the other way. CONTESTED

The frame rate, and why everything turns on it

Patterson said he normally filmed at 24 frames per second but did not check the setting in his haste. The K-100's dial was continuously variable, marked at 16, 24, 32, 48 and 64, with no click stops and no 18 marking at all.

• Krantz wrote that "Patterson clearly told John Green that he found, after the filming, that the camera was set on 18 frames per second." Since the dial has no 18, some suggest he misread 16.
• Krantz, using Igor Bourtsev's analysis, argued that Patterson's height is known (157 or 160 cm), so his running pace can be calculated and matched to the regular bounces in the jumpy opening frames. He concluded "[we] may safely rule out 16 frames per second and accept the speed of 18."
• René Dahinden said the horse footage "looks jerky and unnatural when projected at 24 frame/s," and after timing people walking the creature's path reported: "None of us ... could walk that distance in 40 seconds ... so I eliminated 24 frame/s."
• Munns wrote that "One researcher, Bill Miller, found technical data from a Kodak technician that stated the K-100 cameras were tweaked so even when the dial is set to 16 fps, the camera actually runs at 18 fps. ... I have nine K-100 cameras now. ... I tried it on one camera, and got 18 fps, but the rest still need testing."
• John Napier, usually cited on the other side, thought it "likely that Patterson would have used 24 frame/s" because that speed "is best suited to TV transmission," while conceding "this is entirely speculative." His premise was wrong: 24 fps is the cinema standard and 30 suits American television. Krantz found the K-100 manual, which advises 16 fps for normal screen action on a silent projector.

Not one of these is a measurement taken from the film. Every argument reasons backward from something else. CONTESTED

What Grieve actually concluded

The gait analysis usually credited to Napier's book was not Napier's. It was written by Dr. D. W. Grieve, Reader in Biomechanics at the Royal Free Hospital School of Medicine in London, who studied the film independently of Dmitri Donskoy in Moscow after Dahinden took a copy to Europe in 1971, and it ran as an appendix.

Grieve's conclusion is the most-quoted sentence in the film's defense, and it is conditional: "The possibility of fakery is ruled out if the speed of the film was 16 or 18 fps. In these conditions a normal human being could not duplicate the observed pattern, which would suggest that the sasquatch must possess a very different locomotor system to that of man." The last clause is usually dropped. DOCUMENTED

Two things get left out. Grieve did not settle the frame rate: Daegling reports that he "evaluated the various possibilities" and "did not come to a conclusion between them," and that he "confessed to being perplexed and unsettled" by "the tangible possibility that it was real." And he revised himself afterward in the direction that helps the human reading. John Green's Sasquatch: The Apes Among Us reports that Grieve found "the similarities between the sasquatch gait and a human gait to be very striking in terms of stride length, speed and time of swing" if the film was taken at 24 fps.

This site could not obtain Napier's book or Grieve's appendix and addendum, so the frame counts, stature, weight, foot length and breadth ratios that circulate under Grieve's name are left out. What is verifiable is the conditional above and the fact of a later revision favoring 24 fps. Donskoy, Chief of the Chair of Biomechanics at the USSR Central Institute of Physical Culture, was friendlier, describing "the walk of the creature as a natural movement without any signs of artfulness which would appear in intentional imitation," while "such a walk as demonstrated by the creature in the film is absolutely non-typical of man." Neither report has been reproduced from an audited copy. CONTESTED

Napier is not a witness for the film

Napier is quoted on both sides and belongs cleanly on neither. He wrote "I am convinced that Sasquatch exists." He also wrote of the film: "There is little doubt that the scientific evidence taken collectively points to a hoax of some kind. The creature shown in the film does not stand up well to functional analysis." DOCUMENTED

His two original objections were that the footprint length is "totally at variance with its calculated height," and that the Bluff Creek prints are of the "hourglass" type, of which he was suspicious. He sorted Sasquatch prints into that type and the "human" type found at Bossburg, held that two genuine types would mean two species and that this was beyond reason, then argued at length for the Bossburg cripple foot, calling a hoax there "so unlikely that I am prepared to discount it." Barbara Wasson published a sustained criticism of his reasoning. His closing line is the one everyone remembers: "I could not see the zipper; and I still can't."

Bodies, proportions, and what the arguments establish

Darren Naish put the subject's intermembral index (humerus plus radius over femur plus tibia) "between 80 and 90, whereas in our species it averages 72." Esteban Sarmiento, working from the same generations of copy, concluded the reverse: "In all of the [examined] relative values, bigfoot is well within the human range and differs markedly from any living ape and from the 'australopithecine' fossils." Sarmiento put the weight at 190 to 240 pounds and raised an objection nobody else did, that the pale soles do not match the dark palms and he knows of no mammal like that. He summed up his own position as finding "some inconsistencies in appearance and behavior that might suggest a fake ... but nothing that conclusively shows that this is the case." No audited measurement has settled the index. CONTESTED

Bernard Heuvelmans thought the subject a suited human, objecting to the uniform hair flow, to hair on the breasts as unlike a primate, and to the too-calm retreat. Naish answers the breast point by noting that human breasts are hairy, with fine hairs.

Two strong opinions get cited as though they were findings. O. Allen Guinn III, a board-certified plastic surgeon, published a comment supporting Munns and Meldrum in their own journal, working from a stabilized slow-motion copy the authors supplied, and concluded from skin folds, breast shape, muscle contraction and scapular winging that "it represents a live hominid and not a human in a costume." Stan Winston, an Academy Award-winning effects artist, said on the television series Movie Magic that "it's a guy in a bad hair suit, sorry!" and that "if one of my colleagues created this for a movie, he would be out of business." Neither man published a blinded analysis. ALLEGED

The 1999 Skeptical Inquirer paper "Bigfoot's Screen Test" is routinely called a debunking, and its authors declined the role: "Based on our analysis of gait and problems inherent in estimating subject dimensions, it is our opinion that it is not possible to evaluate the identity of the film subject with any confidence." The compliant-gait finding usually attributed to that paper is from Daegling's later book: "Supposed peculiarities of subject speed, stride length, and posture are all reproducible by a human being employing this type of locomotion." Reproducible is a weaker claim than reproduced. (The journal's byline order is Daniel O. Schmitt and David J. Daegling; most citations reverse it. The text is paywalled and was not read here.) Separately, John Green reports that Meldrum told Daegling he had used "interscye," a tailor's measure across the curve of the back, where the comparison required "chest breadth," and that Daegling put the correction in an endnote while keeping the original claim in his main text. Green was not neutral.

The two men who said they made it

On January 30, 1999, a month after watching the Fox special World's Greatest Hoaxes: Secrets Finally Revealed?, Bob Heironimus of Yakima went public through a press release by his lawyer, Barry Woodard, carried in the Yakima Herald-Republic. That paper's story was headlined that he had passed a lie-detector test; polygraph results are not evidence that a person is telling the truth. He said he had stayed quiet because he hoped to be paid and feared a fraud conviction. His account was first detailed five years later in Greg Long's The Making of Bigfoot (Prometheus Books, 2004), a book not consulted directly here. ALLEGED

On August 16, 2002, Philip Morris of Morris Costumes in Charlotte, North Carolina, said on radio station WBT that he had sold Patterson a commercial gorilla suit by mail order in 1967, believing it was for a prank, and that Patterson later telephoned asking how to make the shoulders more massive and the arms longer. Morris said he suggested football shoulder pads and sticks held inside the hands. He also gave the most specific mechanical account anyone has offered of the walk: long clown feet force a flat-footed stride, and a gorilla head over shoulder pads restricts neck rotation, so a wearer looking behind must turn head, shoulders and hips together. ALLEGED

The two accounts describe different objects, and Long's own book lays out the differences: horsehide against Dynel; a suit Heironimus put at "maybe 20[,] 25 pounds" that "stunk" against a light synthetic with little odor; a two-piece top and trousers against a back-zipped garment; hands and feet attached to the limbs against separate pieces. Heironimus's horsehide claim is secondhand: he said his brother Howard told him Patterson claimed to have made it from a dead red horse.

Each man has named corroborators and no object. Heironimus's mother Opal and nephew John Miller said they saw an ape suit in his car, Opal placing it two days after the filming; friends Russ Bohannon and Bernard Hammermeister said he told or showed them. Morris's wife and business partner Amy vouched for him and said she helped frame the suit. No suit, pattern, receipt or scrap of hide has been produced by anyone.

John Kirk counted the claimants: "There have been too many other people who've come along to say they were the guy in the suit. This, I believe, is number four." Daniel Loxton, reviewing Long's book for eSkeptic on April 12, 2004, is regularly cited as holding that the two confessions destroy each other. He argued the opposite. He framed that objection as belonging to others ("Surely, say critics, one or both of these claims must therefore be false"), then suggested both men could be sincere and largely correct, that if Heironimus wore the suit "it is not clear how he would have known how it was made," and that "after 37 years his recollection of the suit's materials could easily be faulty."

A re-creation was filmed on October 6, 2004 at "Cow Camp" near Rimrock Lake, 41 miles west of Yakima, six months after Long's book appeared. Daniel Perez reported in Fortean Times that National Geographic's producer Noel Dockster "noted the suit used in the re-creation ... was in no way similar to what was depicted in the P-G film." That is a bigfooter quoting a producer, not a published test.

Money, custody, and a missing original

Patterson's finances are relevant and should be stated plainly. An arrest warrant issued on October 17, 1967, three days before the filming, over the rented camera he had kept past his contract; the charge was dismissed after he returned it in working order in 1969. Vilma Radford held a $700 promissory note "for expenses in connection with filming of 'Bigfoot: America's Abominable Snowman,'" against a promise of $850 plus five percent of profits. Twenty-one small local creditors sued him through a collection agency. He had been shooting a Bigfoot docudrama since May or June 1967 using volunteer acquaintances, among them Gimlin and Heironimus, and he exhibited the footage commercially afterward. DeAtley put his own 50 percent share of the resulting film's profits at $75,000. In 1974 Gimlin, financed by Dahinden, sued DeAtley and Patterson's widow Patricia for the one-third share he had never received, and won in 1976. Long reports a 1978 settlement giving Dahinden 51 percent of the footage and video rights and 100 percent of all 952 frames, leaving Patricia Patterson the television rights and 49 percent of the footage. The film is in the United States public domain, having been published in 1967 without the copyright notice American law required between 1964 and 1977. All of that is motive and opportunity. None of it is evidence about what is on the film. DOCUMENTED

The camera original is gone. Patterson had ceded it to American National Enterprises, which went bankrupt a few years after his death in 1972. Peregrine Entertainment bought the company, Century Group of Los Angeles bought Peregrine, and when Century Group went bankrupt in 1996 a search of its Los Angeles storage failed to turn up the footage. Munns writes that the original was "last seen by researchers René Dahinden and Bruce Bonney in 1980," when Dahinden persuaded a Southern California vault to release it and made Cibachrome images, and that it went missing from its numbered location sometime between then and 1996. Every analysis published since works from copies. DOCUMENTED

What is actually unresolved

Little of the popular version survives contact with the sources, in either direction. Napier did not endorse the film; he believed Sasquatch existed and thought this film pointed to a hoax. Grieve did not endorse it either; he built the case that most favors it, on a condition he declined to settle, then revised himself toward the human reading. Schmitt and Daegling did not debunk it; they said the subject's identity cannot be evaluated with confidence, and the reproducibility argument attributed to them is in a later book. Loxton, cited by skeptics as showing the two confessions cancel out, argued that they can be reconciled. The "56 to 65 line pairs per millimeter" figure is a mangling of three published numbers that disagree.

What remains open is narrow and stubborn. The framing speed is not recoverable from the film, and it decides the biomechanics. The camera original is lost, so the best image data is a generation or more removed, and the resolution and focus claims made for it rest on one transparency and one tree branch. No suit, pattern or receipt has been produced, and no body, bone or hair tied to the site. Gimlin, still living, has never recanted. Patterson never did, and died in 1972.

The film is a genuine artifact of October 1967. What walked across that sandbar is not established, and on the evidence as it stands it cannot be.

Sources

Read directly.

• Bill Munns and Jeff Meldrum, "Analysis Integrity of the Patterson-Gimlin Film Image," The Relict Hominoid Inquiry 2:41-80 (2013). Full PDF. Source of the VFC-2 inventory, the resolution and focus discussion, the motion-blur count, the frame-blending explanation, and the open lens footnote. isu.edu
• O. Allen Guinn III, M.D., F.A.C.S., Comment on Munns and Meldrum, The Relict Hominoid Inquiry 2:125-130 (2013). Full PDF. The paper commented on is Munns and Meldrum, "Surface anatomy and subcutaneous adipose tissue features in the Patterson-Gimlin film hominid," 2:1-21 (2013). isu.edu
• John Green, review of David J. Daegling, Bigfoot Exposed (AltaMira Press, 2004), The Relict Hominoid Inquiry 1:16-22 (2012). Source of the interscye dispute.
• The Relict Hominoid Inquiry editor page, confirming Jeff Meldrum as editor and a full professor in Idaho State University's Department of Biological Sciences; ISSN 2165-770X. isu.edu
• Daniel Loxton, "Bigfoot, Big Con: A Review of The Making of Bigfoot," eSkeptic, April 12, 2004; reposted 2025. Source of Kirk's count and of Loxton's reconciliation argument. danielloxton.com
• Darren Naish, "Frame 352, and all that," Tetrapod Zoology, November 29, 2006. Source of the intermembral index, the hairy-breast counter, and verbatim Grieve and Donskoy quotations. darrennaish.blogspot.com
• Daniel O. Schmitt and David J. Daegling, "Bigfoot's Screen Test," Skeptical Inquirer 23:3 (May/June 1999), p. 20. Byline and citation from the publisher's page; full text paywalled and not read. skepticalinquirer.org
• FCC Census Block API, queried at 41.440278, -123.701944, returning Del Norte County, California.
• Open Library full-text search, used to verify quotations inside books not otherwise obtainable: Grieve's "possibility of fakery" conditional (in Hunter and Dahinden, Byrne, Bord, Meldrum and others), Grieve's later revision as reported in John Green's Sasquatch: The Apes Among Us, Donskoy's "absolutely non-typical of man," and Napier's "I could not see the zipper."
• Bigfoot Encounters' reproduction of the Bossburg chapter from Don Hunter with René Dahinden, Sasquatch/Bigfoot, carrying Napier's quoted assessment of the Bossburg cripple foot.
• "Patterson-Gimlin film," Wikipedia, and its cited sources, for the October 20-23 chronology, the camera rental and arrest warrant, the filming-speed debate, the Radford note and creditor suits, the Gimlin suit and 1978 settlement, public-domain status, the custody chain and loss of the original, the Heironimus and Morris disclosures and the catalogue of differences between their accounts, and quotations from Napier, Krantz, Dahinden, Munns, Sarmiento, Heuvelmans, Winston and Daegling. en.wikipedia.org

Not consulted, and so not quoted at first hand.

• John Napier, Bigfoot: The Yeti and Sasquatch in Myth and Reality (Jonathan Cape, London, 1972; E. P. Dutton, New York, 1973). All Napier material here is quoted at second hand. Catalogs and secondary sources disagree over whether the subtitle runs "Yeti and Sasquatch" or "Sasquatch and Yeti."
• D. W. Grieve's appendix and addendum in Napier. Not obtained. The frame counts, stature, weight, foot length, stride and breadth ratios circulating under Grieve's name are omitted for that reason.
• Greg Long, The Making of Bigfoot: The Inside Story (Prometheus Books, 2004). Cited only as the published vehicle for Heironimus's claim, via Loxton's review and Wikipedia's citations to it.