Bigfoot Encounters

The Patterson-Gimlin Film: An Analysis
By Noah David Henso

March 2, 2009 -- A note from the author: My name is Noah David Henson. I've been studying human muscular and skeletal anatomy since 1984, both as a professional illustrator and as a student of physical anthropology. I studied collegiate anthropology, including primatology and human evolution, from 1988 – 1993, with enough hours to establish a minor in the subject attendant to my BFA from Texas State University. I've been examining the bigfoot phenomenon, skeptically and with an emphasis on the aforementioned skills, in earnest since 2003. My intellectual interest in the subject goes back to my childhood in the 1970s and 80s.

This paper constitutes a skeptical analysis of a digitized, B&W video version of the 1967 Patterson-Gimlin film available on youtube, here (and embedded above). It's 1:06 (m:s) in length, as posted by Youtube member Squatchinc on December 23, 2007, sourcing a digitally restored and enhanced video made by MK Davis.

This paper also references Part Two of the 1997 NASI Report on bigfoot, written by J. Glickman, Part Two, available at

Here is a breakdown of the progression of the 1:06 video, of which only the first thirty-three seconds are of interest for the purposes of this paper:

  • :01 - :04 – Forward-then-reverse playback of the figure in forward ambulation
  • :05 - :06 – Figure in forward ambulation
  • :07 - :12 – Freeze-frame : Extreme close-up of figure's facial profile (no crown visible)
  • :13 - :17 – Freeze-frame : Extreme close-up of figure's frontal face (with visible crown)
  • :18 – :20 – Figure in forward ambulation with arms spread, turning back to look at camera
  • :21 – :23 – Forward-then-reverse playback of figure in forward ambulation
  • :24 - :26 – Figure in forward ambulation behind and between two vertical white trees
  • :27 - :30 – Extreme close-up of figure's right hand, with visible thumb flexion
  • :31 - :33 – Figure in forward ambulation

For anyone interested in investigating the possibility that this film might depict a man in a suit, I recommend watching the video several times, finger depressing the pause button in various spots along the progression so as to examine the gait, musculature, limb proportions, and the distribution of hair — all of which, to my trained eye, appear to be non-human and which taken together exclude the possibility of a person in costume.

The most compelling frames for examining the footage occur at :13 – the frontal face close-up – at :18 – the upper-torso turn-back with arms spread – from :21 to :23 – in which a close analysis of the back muscles and hip muscles can be undertaken – and from :27 to :30 in which the thumb can clearly be seen to flex.

:13 is compelling because it shows the figure's right eye (viewer's left), along with the nose, lips, jaw, cheeks, crown and a hint of ear. If this is a mask it is most ingenious. First, it doesn't look like a mask of any known primate; non-human primates have very thin lips and wide nostrils, but here the figure is shown to have thick, bulbous lips and no visible nostrils. These features discount the possibility, at least, that the “mask”, if it is indeed such, was store-bought or mail-ordered. If it is a mask, it was custom-made by a hoaxer(s), which at this point in examining the film, the author must concede is certainly a possibility.

:18 is compelling because it reveals the figure's two pendulous breasts, and is an excellent frame by which to measure the length of the arms. The visible breasts once more make it highly unlikely that this could be a suit, unless the hoaxer(s) was so ingenious as to add mammary glands to a suit that did not originally have them (as no store-bought suit would have), in order to depict a creature that until that time had only been reported in the media as being male. It must be admitted, however, that such ingenuity is possible, if unlikely.

It is the length of the arms, taken together with the visible thumb flexion (at :27, discussed below) that I consider the single most convincing feature of this figure. In anthropology a measurement called the Intermembral index (IM) is used to convey the proportion of the arms in relation to the legs. In humans, this IM is typically about 70. Chimps have an IM of about 107, and gorillas 117 (these numbers can be verified at various sites around the web). The figure in the film has a measurable IM of between 85 and 90 [Green, 2004].

Another way of looking at the arm length is to compare its length to the overall size of the body. The NASI report written by J. Glickman scientifically and unequivocally establishes the height of the figure at 7'3?. Here is how Glickman calculated that height (edited and summarized by the author from the NASI report; Glickman is quoted in quotation marks):

An accurate spatial reference has been established from research photographs taken by Byrne and Hodgson in 1972 at the Bluff Creek site [Byrne, 1972]. In one photo, NASI's Fig. 4, Hodgson is standing behind a fallen tree trunk that is also visible in the Patterson film, holding a vertical scale measuring stick that is marked every six inches. In this photo, Hodgson's feet are visible and he is in the same 2-axis (that is, two-point perspective) plane as the vertical scale. His height can scientifically be established as just over 6 feet. In a separate reference photo taken by Byrne, Hodgson is seen moving through a 2-axis image plane that the subject moves through in frame 326.

“Since the height of Hodgson has been established and since he is in the same 2-axis plane as the subject, Hodgson's height may be used to measure the subject's height provided that the scale of the two photographs can be matched.

“Both images contain a dead tree, the size of which has not changed during the intervening five years which is used to match the scales of the two photographs. During scaling, three points were used to validate that the tree had not changed size.

“Figure 6 is a digital composite of the film subject and Hodgson in the same image plane with a common image scale established by the dead tree. Note the successful planar alignment of the feet in this matched scale composite. Hodgson' height in pixels in 276, and the height of the film subject is 327. A simple ratio is used to compute the size of the film subject:

276 pixels / 327 pixels  = 6'1¾” / x . Therefore, x =  6'1¾” X (327 pixels / 276 pixels.

Thus the computed height of the subject in the P/G film is 7'3½”. An error analysis has not yet been undertaken, but in other similar forensic situations it is typically +/-  1”.

Using the height of 7'3” as a scale reference, Glickman calculates an arm height of 161 pixels, or 43”. The standard arm length of a 7'3” human is 38.5” [Winters 1990]. The subject's arm-to-height ratio is thus measured at .49H, when the standard human number is .44H [Winters 1990]. The percentage of the global human population who possesses this arm-to-height ratio is quoted as 1 out of 52.5 million people [Weimer 1993]. Combined with the height of the figure and the comparatively short length of the legs, the percentage of the human population who could have all three of these unusual features — extended arm length, contracted leg length and astonishing height — becomes so astronomical as to be statistically impossible. The only explanation is that the figure is either 1) an uncatalogued animal, or 2) an extremely ingenious, expensive and well-crafted suit.

Glickman notes:

“This suggests that if the subject is a human in a costume then some form of arm prosthesis is in use. Finger and hand flexion is observed in the film [see :27, below] which implies the prosthesis must support flexion. The use of such a sophisticated prosthesis appears to be at odds with the year the film was made, the technology available at that time, and the financial resources of those involved with the filming.”

:21 to :23 are compelling because here we can closely analyze the figure's back muscles and hip muscles, which not only can be seen sliding over the figure's underlying skeletal structure, but which expand and contract in a realistic fashion. There is no known mechanism by which a suit manufactured in 1967 — by Hollywood professionals such as John Chambers, let alone by a couple of middle-income amateurs — could effect the illusion of shifting, expanding muscles. It simply could not be and was not done at the time. All Hollywood suits up until the 1970s were shapeless, baggy, and/or loose-hanging suits with no visible musculature. (Even big-budget ape movies of the 1980s, such as Greystoke and Gorillas in the Mist, with expensive and articulated suits developed by industry greats Rick Baker and Stan Winston, respectively, do not depict muscular action seen in the Patterson-Gimlin film.) Also of note is the distinct lack of any material folding, rippling or wrinkling. There is no known material, outside of animal or human skin, which does not create visible folds as it is bent by the limbs which it covers.

:27 to :30 are compelling because, as noted above in the section on arm length, we can clearly see the thumb flexing. There is no known prosthetic device, available in 1967, which could have effected such flexion inside of a costume or suit. Such technology simply did not exist. The only conclusion based on the evidence is that this is a real arm and hand, and not a costume or suit. Since the proportions of that arm are non-human (again, see above), the only conclusion can be the film depicts a non-human figure.

Reviewing the seventeen seconds of video discussed above, we can see at least two compelling features of the hair: One, it is variable in both length and density — that is, in some places, such as the lower torso (or external oblique area, just above the hip), the hair is short and sparse, whereas in others, such as the arm, the hair is long and thick. And two, the hair is variable in color. This can be seen even in the black-and-white video under review here, in which the shades of gray vary even under direct sunlight (that is, without shadows being cast upon it). There is no known ape costume, available in 1967 or for a decade or more following, which depicts hair in shifting densities, length and coloration. All Hollywood ape costumes, until Rick Baker and Carlo Rambaldi's work on King Kong in 1975, were of uniform hair length, density and coloration.

My conclusion, after analysing the film footage countless times, employing a degree of expertise in human and primate anatomy, and examining critically the analyses of forensics expert J. Glickman of NASI, among others, is that the 1967 Patterson-Gimlin film does not and cannot depict a human being in a costume. It is a real, as-yet uncatalogued animal, most likely a primate of either pongid (ape-like) or hominid (human-like) taxonomic classification, that resides, or once resided, somewhere in the millions of square miles of human-uninhabited forests of the Pacific Northwestern United States and Canada.

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