I can only speculate. The witness to the squating sasquatch was quite definite about the distinct C-shape. The degree of flexion would have to be sufficient to allow the pressure ridge in the laverty photo to bulge up with nothing above it to compact it (as was pointed out by Jim).

You can get a sense of this from the gifs MK Davis has put together. Once I got him to take a closer look at the feet, he found a number of claer examples that show the midtarsal flexibility of the foot and the relatively long toes.

If the sasquatch foot is anything like other apes the deep plantar ligaments, those below the calcaneocuboid joint and the talonavicular joints are substantial and capable of elastic storage. One time I had access to an anesthitized chimp with the object of manually flexing the foot and x-raying it in that position to compare the configuration of the tarsal bones. The stiffness of the ligaments made it impractical to do that and keep them in position for the radiograph.

I don't suspect the sasquatch foot is suited for extended running. But just consider its habitat -- where would it "run" like a human would run in a field or on a track? Its flat flexible foot and relatively longer prehensile toes are ideally suited for climbing on steep broken choked terrain.

Click to view attachment

Quote: Dr. Meldrum-

"I don't suspect the sasquatch foot is suited for extended running."

"Its flat flexible foot and relatively longer prehensile toes are ideally suited for climbing on steep broken choked terrain."

This is the kernel of my question......

Wouldn't this type of foot morphology, & the speculative "Grand Design/Reason" for a foot like that, be more of an attribute of a "tree-climbing Primate" than a "cross-country-skiing-type" Giant Biped ?

Thanks for your response.... I know you're a busy man.

----
Edit to add: The animated gif in the above post, very clearly shows the 'flexion' in both feet that I've been asking about.....especially in the right foot.
Her toes bend up... & then go "FLAP!" into the step.
INCREDIBLE!
Thanks for showing that particular segment.... it does clearly show what you are describing, Dr. Meldrum !

Just a shamelessly self-serving note about my avatar. It is intended to depict the cover art of my forthcoming book, an expanded companion volume to the Sasquatch: Legend Meets Science documentary, with a release date of 8/31/2006 from Forge Press. Alot of the items raised here are discussed and explored in much greater depth there.

That will be the book EVERYBODY will have to have !!! :new_thumbsupsmileyanim:

I'll be more than happy to pay top dollar for a signed copy, Doc !!!

It'll go right beside my signed, first edition, hard-bound copy of John Green's "The Apes Among Us"
& my signed, first edition copy of Chris Murphy's "Meet The Sasquatch" !!!
Can't wait !!!
I know it will be AWESOME !!!!

I have changed the title of this thread to 'Questions about', rather than 'problems with', which is I feel a more appropriate title.

There are certainly some factors common to tree climbing and scaling a steep mountain side. The principal difference would be the texture of the substrate -- trees with cylindrical supports of varing diameters, and mountainsides with soil or angular rocks most frequent. So what is the starting point for the evolution of a sasquatch foot? What traits might be useful to retain and what might be modified to varying degrees? The starting point is certainly an ape, but an ape that is already largely restricted by its mass to a terrestrial habitat. Here is a sneak peak of a figure from my book (chimp/lowland gorilla/mtn gorilla/sasquatch). Note the modest transition in the series from a mountain gorilla to a "typical" sasquatch foot.

Click to view attachment

I contend that the human arch was a rather recent innovation that only became significant after the skeletal gracilization (lighter boned and lighter muscled physique) of Homo sapiens, first 200,000 to 400,000 years ago.

Look at the Terra Amata footprint in the PDF of my paper attached in an earlier post and tell me if that 800,000 year old hominid footprint doesn't bear a stricking resemblence to a small sasquatch footprint.

August? Oboy!

Between that and Dave Murphy's book, all my reading time will be taken up. I can hardly wait!

Ditto that LAL!!

Quote: Dr. Meldrum - "Look at the Terra Amata footprint in the PDF of my paper attached in an earlier post and tell me if that 800,000 year old hominid footprint doesn't bear a stricking resemblence to a small sasquatch footprint."


Indeed... it DOES ! , Dr. Meldrum !!!

....I think I see where you're goin' with this.......

where you're coming from.....

as it applies to the Sasquatch phenomenom & the apparent divergence of MAN & APE.....

and, that's REALLY HEAVY, MAN !!!

and, I'm learning ALOT from you !!!


(...think of the tuition fees I'm savin' on over here !!!) :new_thumbsupsmileyanim:

I must admit, when I first viewed the above image I thought the foot to the far right was human, which leads me to wonder...

how is it possible to transfer your expertise in primate feet to an undiscovered, uncatalogued, unknown species? Isn't it all [bone details/reconstruction, degree of flexion, midtarsal flexibility, etc.] a good guesstimate at best?

RayG

One of the best threads on the bff here, period.

This should be in a "classics" category.

Thanks for checking it out and Participating, Dr. Meldrum. Have learned a lot.

Scott

I prepared some comments Friday but forgot to email them to my home. Anyway, I made a graphic (on the left) that I thought helped me see some things. I wanted to study my interpretation of Dr. Meldrum's explanation in detail and see if it made sense to me. I took what I believe is Primateer’s enhanced photo of Patty’s right foot which is very consistent with casts. I placed little blue spots on the double b*lls. Then I placed Dr. Meldrum’s reconstruction over the print. I didn’t get a perfect fit but it was pretty close. You wouldn’t expect a perfect fit in a living creature. Obviously they were constructed from different media and different angles but I thought it was interesting looking at the “real” foot. If I understand Dr. Meldrum correctly, the ball closest to the big toe is theoretically similar to the pads on the palm of our hand underneath the knuckles. In his interpretation, there is actually a crease or split in the ball (forming the double ball) presumably to facilitate movement of the long flexible toes. To me this interpretation is now very plausible and Dr. Meldrum makes a compelling case.

There are still a couple of things that trouble me regarding the long toes and the exact mechanism in the formation of the ridge in the Laverty photo. I would expect that a giant hominoid approaching 1000 pound would exert extraordinary forces on the toe bone. Dr. Meldrum is certainly correct that a compliant gait, bending the foot in the middle, and other behaviors would reduce the forces on the toe bone but there are reports of them running fast. There are reports of them climbing cliffs. Also there are times they would step on rocks. I am certain Dr. Meldrum has considered these factors also. This does not indicate his toe length is necessarily too long, only that the long toe bones would be under tremendous stress and I think it would have to be very strong to accommodate any of these activities. Perhaps the reports of their athleticism are incorrect or exaggerated.



Since my two posts merged into one, I had to edit this a bit. On the right graphic, I placed the shortened metatarsal (blue bone) which I originally thought seemed the best explanation based on my previous knowledge. I am still not convinced that it is not a plausible explanation, but certainly the flattened joint surface in humans and apes makes a highly flexible joint here somewhat of a problem. If bigfoot were closely related to humans, I would think this would make this interpretation even less likely. It still seems kind of odd to me. I would think that the rounded pads might indicate that it was dissipating stress from a point (the joint) as the stress was dissipated radially from the joint. Logically, two rounded pads would indicate two joints, at least that was my thinking. Hopefully the graphics were fairly accurate and easy to understand. I thought they were a help to me.

Awesome topic! Kudo's to both Jim and Dr. Meldrum for great questions and answers.

I won't even begin to address the foot anatomy subject. However, with Jim the geologist and Jeff THE sasquatch foot expert both on this thread, - it seems the perfect opportunity to bring up something I've been kicking around.

Correct me if I'm wrong, but to my knowledge there is no standard for measuring soil compression in association with footprints. It seems to me that this would be rather useful information when estimating the weight of a footprint subject. Before I go any farther, let me say that I do realise this is not a simple matter of applying a linear soil compression factor to a "depth averaged" footprint measurment, multiplied by it's area to yield a subject "weight". That said, I don't think it would be unreasonable to expect that fairly accurate weight data COULD be gleaned from soil compression data collected in situ with fresh print castings and measurements. There should be some geological standard (and possibly tools?) for measuring soil compression that could add a whole new dimension (and "weight") to the growing database of footprint evidence.

Jim? Dr. Meldrum? What say you?

Correa Neto's reply to Dr. Meldrum:


"Originally Posted by LAL :
Since Correa evidently didn't have time to present his argument to Dr. Meldrum, I did it for him. This is the reply:

LAL,

Sorry, but after taking a quick scan through the other lists you are participating in, I don't think it is worth my time to respond more than just briefly to the latest criticisms. They are of a different nature than the points raised by Jim. ...snip...

http://www.bigfootforums.com/index.p...0&#entry300929


First of all LAL, thanks for submitting to Meldrum the incoherencies I found. Its beter than just using the standard appeal to authority. And also, whenever you have the chance, please send a "Thank you" to Meldrum. I'm also a busy man and I know how hard it is to find spare time.

Now, I am sorry to say, but the answer has not convinced me, quite possibly because he was in a hurry. Please allow me to tell why:


Neto clearly has no concept of the calculation of the mechanical advantage of the triceps surae (calf musculature) as evidenced by his comments and attempt to diagram his point.



Note that my diagram shows that the bones act as levers that rotate around joints (the articulations). The longer the lever -bone in this case- the more efficient will the transmittion of the energy will be. Muscles generate the energy to rotate the bones (actually bones play a double role is double since they also provide support to the muscles). The longer the lever, more efficient will be the transmittion of the force. Meldrum´s bigfoot foot model shows short "levers" when compared with a human foot. Also, note that there's an extra articulation. Beside the greater complexity, this induces extra waste of energy due to attrition. What also means its not as efficient as a human foot in terms of energy saving and transmition when walking. And will also be an extra wear point. The only way to compensate for this is by raw force, increasing the sizes of the muscles involved, may not be a sound approach (more muscles = more energy needed to feed). So far, I am not convinced...


The model of the sasquatch foot is a very natural extension of trends displayed in a size-graded sample of ape feet from gibbons to chimps to lowland gorillas to mountain gorillas, not only in relative elongation of the heel but in lessened divergence of the great toe. Humans have departed from this pattern by adopting a fixed arch.

The MT break has little to do with the loss of divegence of the big toe, until the fixation of the arch, at which point the aligned big toe becomes the distal support of the arch. There are a number of interacting modifications at play during the evolution of the modern human foot.



Well, gibbons, chimps, lowland and mountain gorillas have different ecological niches than the ones bigfeet are supposed to have and the species from the genus Homo have or /had. gibbons, chimps, lowland and mountain gorillas are not fully developed bipedals. Homo and bigfeet (assuming they are real and the usual suppositions about them are correct) are bipedals, adapted to stride along great distances across the terrain. Am I correct untill now? Thus, since the evolutionary proccesses tend create similar forms to achieve similar tasks, the feet of humans and bigfeet (assuming the last ones are real) must share a lot of features. The rigid arch is an example. The position of the big toe another. Even with all the "interacting modifications at play", since the evolutionary pressures were similar.

And also we must remember that if what some of the pictures show are real bigfoot footprints, they -apart from their size- are virtually indistinguishable from those produced by humans. And since a footprint is a mold of the foot that made it, and since foot shape is a function of bone structure and attached muscles, why should the foot that made those footprints (assuming it was a real foot) have a different bone structure?

And yes, I have scrolled down the page and I saw the feet comparsion. Call me obtuse if you want, but I fail to see the "modest transition in the series from a mountain gorilla to a "typical" sasquatch foot". Note I posted a similar comparsion ages ago to show how different they are.

See? I am still unconvinced. The answer don't seem, IMHO to have really touched the issues I raised. Actually it seemed quite vague. Understood what I wrote LAL? Because I tried to make the explanation as simple as possible so everybody interested in the subject can understand.


(Some people should do the research required before asserting their opinions with such conviction.)

Sure. I can't help but agree with the above statement. Really. Honestly.


The comments about the casts and footprints illustrated on my webpage and the comaprisons made between the Laverty photo are simply without merit.


Not sure if its directed to me, but if it was, I think the above statment is without merit, thus I will not answer. If not, sorry, nothing to see here, move one, move on."

<snip>

Thank you, Dr. Meldrum, from Correa.

http://forums.randi.org/showthread.php?p=1487070#post1487070

Any comments? Anyone?

BipedC,

I can't say I know much of anything about geology or biomechanics but have studied soil mechanics somewhat extensively on a formal level. Soil is a very dynamic medium that does for the most part, perform predictably under static loading type conditions. It's a fairly simple process to determine how various homogenous substrates(over a variety of conditions) will preform when subjected to given loads vs. surface area of support in respect to deformation.

Every attempted analysis(Daegling, Krantz, Farenbach et al) I've ever read whose goal was to draw some correlation between between the depth of alleged sasquatch tracks(i.e. compression) and the corresponding force vectors associated with the given compression has been seriously flawed IMHO.
Most of these respective analysis simply attempt to treat the sasquatch foot almost as if it were a static bridge pilling with known area of support equal to the surface area of the purported track. This is usually then compared with known quantities (again assuming basically static loading conditions) in respect to to the supposed sasquatch track with some conclusions being drawn on a linear relationship between the two.

Again, I know nothing about biomechanics but from a strictly engineering standpoint, I'm agreeing with the notion that the purported sasquatch would have to have a much more flexible foot than say humans would. With that assumption in mind, the realisitic area of support(of a real sasquatch foot instead of being either a linear(or fairly simple nonlinear relationship) in respect to the known surface area of the track, becomes a fairly complex integral equation in respect to the changing width of the print along it's respective length. (Think of the way the tire on a car contacts the ground but include the variable that the width of the foot unlike the width of the tire is changing from back to front) Add to the unknowns involved that both the magnitude and direction of the force vectors applied to an moving, integral area of contact(i.e. support)across the width of the foot are almost certianly not constant across either the width, nor the length of the foot of a walking sasquatch. Add in again the unknowns of how the relationships on how those respective force vectors change in magnitude and direction being applied by the sasquatch and also the potential of how the timing and the magnitude of the integral area of support may also change as the sasquatch speeds up/slows down. What you get is an absolute mess of very complex, ever changing equations to attempt to develop, based on several assumptions (which there's no way to really gage or ascertain their accuracy) on how the sasquatch foot difinitively operates under loading and unloading. No matter how well developed your mathematical model may be, it's only going to be as good as good as those assumptions you are forced to make in order to develop them.

Add in a myriad of other unknowns including but certianly not limited to: the changing force vectors applied by the sasquatch as it traverses nonplanar terrain, the change in soil conditions between the time the print was deposited and the time the various core samples from the print(s) was collected, the human errors introduced by several data gatherers, the fact that most substrates are rather unpredictable under dynamic loading, etc.

What you've got is a whole lot of calculator gymnastics to develop a good model, with no real way to gage the degree of uncertianty involved.

The only thing I'd be willing to conclude with any degree of confidence about various existing analysis offered up by both the proponents and skeptics on depth of print vs weight of print maker is:

1- That the relationship is probably more of a function of the width of foot leaving the impression rather than surface area.(If indeed the impression is real)

2- If the impressions being analyzed are real, the respective sasquatches that left them, didn't need to be anywhere near as massive as was concluded.

There should be a new section titled required reading for BFF members.
This thread should be one of the first placed there.

WillinYC wrote:




:appl:

Lal,

Dr. Meldrum already stated he didn't want to be part of the discussions on JREF. I think since he has already taken the time to come here and explain his work and theories it'd be best to respect that instead of relaying responses back and forth between forums. Correa has the option of coming here with responses.

I don't want to speak for Dr. Meldrum, but maybe I can state what I know about these theories.

The problems stated about the sasquatch foot can be compared to the problems seen in the anatomy of a known hominid, Australopithecus Afarensis. Afarensis had both bipedal and arboreal characteristics. It's said they lacked an arch in the foot, though their feet have been said could still act as human feet do. Their wrists show arboreal traits. Their body proportions are suited for both. Their phalanges are longer and curved than in humans.

These same arguments of principals of physics and energy efficiency have been debated about Afarensis. It would take a lot of time and effort to post all the debates about Afarensis here, more time than may be appreciated.

What does that mean? Well, as far as can be compromised, Afarensis had both abilities because they were both. They were mostly bipedal but they had to often take to the trees. Why?

We know that Australopithecines were hunted by Dinofelis. They may have had to frequently be swift in the trees to escape Dinofelis. However, the leopard-like Dinofelis could aslo climb trees. An adaptation to both may have been beneficial to esape these known predators.

What can this tell us about sasquatch?

Well, there may be a reason sasquatch also has these adaptations. A longer lever like the arch of the foot may be great for long distance travel across a flat plain to wear down the endurance of a prey animal or long distance migrations across the globe (which is the theory for why humans developed the arch), but is it truly beneficial for steep rocky terrain or even the occasional tree climbing?

When we go hiking up a mountain, we are often forced to traverse back and forth in a crisscross pattern up steep inclines. Going down hill also can be dangerous or slow going. Our long arches can easily trip over rocks and sticks and other obstacles if we were to start running either up or down because for the most part we are adapted to running on flat ground. Twisted ankles are common, and a broken leg in the wild could prove fatal.

Now imagine our feet were flexible right in front of our ankles, and our toes could really grip the ground and objects on the ground. Mountain climbers can really appreciate this, as they use their toes a lot to grip small ledges to climb rock faces. Without the safety of ropes and the protection of climbing shoes and other mountain climbing tools the benefit of a good, strong flexible foot would be very beneficial.

To put this in a much simpler way, my daughter has very agile feet. She's very young and uses her feet to climb a lot and to pick things up off the ground. Not long ago I saw her curl her toes up into a fist. I freaked out and busted up laughing! I tried and tried but after a lifetime of walking on the hard flat ground and not using my toes but to push off on the flat ground I just couldn't do it. I even had to use my hand to force my toes to curl as the muscles were not used to moving in such a way. It was no surprise when I found out a little later she was the only one in her class who could climb the rope to the top in gym class, because she could use her toes like that.

Another reason for arboreal traits found in sasquatch may be the need to escape a predator by climbing a tree, especially when they are young.

This may be theory, or close to a "Guesstimate", but there is precedence seen in known hominids.

Did I ask him to be part of them? I PMd him prior to posting and got my questions answered on the board.



He won't. I asked him months ago to e-mail his arguments to Dr. Meldrum rather than trying to convince me. He said he was thinking of writing a paper, but didn't do it. I posted the link to this discussion and suggested he join in. I told him he could just copy and paste the argument from the thread it was on. I suggested he ask another member on both boards to post it for him. Finally, I posted it, and I'm very satisfied with the response from Dr. Meldrum.

Correa asked me to convey his thanks, which I did. I also posted most of the rest of the post. I then asked for "Comments? Anyone?"

I gathered Dr. Meldrum had already stopped posting here and I didn't expect another answer from him. I thought others might have something to add. I've already answered Correa's post on JREF, but my knowlege of Physics is zip, so I thought someone with more expertise than mine might care to comment on these good-sounding but apparently very flawed arguments.

I'm here to learn.

Thank you for the rest of the post.

Oops, something I forgot to add, is that with a flexible gripping foot, instead of traversing a mountain back and forth to slowly make our way up it, we could just go straight up or down it. Now that would save a lot of energy!

Great feedback, - thanks! You just confirmed my suspicion that there is a great deal of dynamics involved although I could have stated it better:


Still, even with the extensive "calculator gymnastics" I can't help but think that the end result of displacing "x" amount of "y" type of soil, is the summation of "z" total applied downward force. I also think that the apparent "flexibility" and "load spreading" characteristics of the Sasquatch foot model would tend to average the load distribution, thereby making "weight" (force x area) easier to calculate. It seems to me that the very "flatness" of alleged Sasquatch prints is a clear demonstration of "load averaging". If the load distribution uniformity of the foot was low or non-linear in nature, then accordingly there should be much greater variation in soil compression, - but this does not seem to be the case.

Maybe the way to go about this is by applying foot models under varying loads to a standard "soil" in a laboratory setting. Once a "foot dynamics" model has been developed using this approach, variations in dynamics can then be taken into account in field settings, provided a reasonably accurate soil compression factor can be measured.

While way out of my league, it sounds like an excellent thesis project for one of Dr. Meldrum's star students.

I wrote a nice long post the other day to try to answer Jim's question when my computer crashed, gotta love 'the bush.'

The first time I handled a live ape foot trying to see for myself how flexible the midfoot was, I was astonished at how INFLEXIBLE it was. I couldn't get even close to the flexibility shown in Jeff's great work with a young chimp, even with a young chimp. Gorilla feet are even less flexible. And this isn't an effect of the anesthesia.

I think the point is, and hope Jeff would agree, that we aren't talking about a truly mobile joint here, just a little bit of flexibility- maybe 10-15 degrees, which I'm sure he can better explain is all it takes to see what we think we are "seeing," and fits nicely into the evolutionary trend.

I had some more thoughts on sole pads and why I'd expect the opposite of what Jim suggested (that is that if the foot is flexible in a spot I'd expect LESS padding there- like on all other joints) but Jeff has already nicely articulated and illlustrated the case in great apes.

On last thought on toe placement in hopes of stimulating further discussion. As Jeff has shown, adult mountain gorillas tend to have relatively forward placed and almost pointing big toes, but this isn't the case for young mountain gorillas whose feet more closely resemble the chimp's in Jeff's diagram. I've recently wondered about this and can't remember if I managed to post this image elsewhere in the forum or not. The observation can be explained in two ways that are obvious to me, and perhaps more that I hope others can come up with. 1) younger gorillas are much more arboreal and therefore need a better grasping big toe, and 2) adult gorillas are lot heavier and their feet are therefore adapted to better carry that large weight. Obviously these two factors are related and there is also some measure of maturation involved.

So, scaled for length, here is an ~3 yo female MG foot (left) compared to an adult (~25 yo) female foot. Mass difference of about 20 kg versus 110 kg. And note that the adult foot doesn't have the toes as extended as in the infant foot.

Anyway, chew on this for a while if you like.

Apeman

Stole a bit more time to work on/think about this....

Here's a more complete group of feet. Still not perfect and deceptive in a lot of ways, but better shows the sort of forward progession of the big toe I'm thinking about. Keep in mind that if big toes on feet #3-5 were fully extended, they would look quite a bit more like #2. You can see the nails on the sides of the big toes on #3 and 4 (5 had an injury) which further shows that their postitioning, though relaxed, isn't correct in terms of how the foot hits the ground when walking/weight bearing. I'd argue that the position of the big toe for the mountain gorilla in Jeff's diagram, which I've included in reverse, is also a bit deceptive in that it should actually be more extended when weight bearing and not pointing as forward as it does. I'll try to find some shots of gorilla feet while walking to make a more convincing point, but that's a difficult task in the vegetation they live/walk in.

Nonetheless, we have 3 juvenile gorillas of progressive age (about 2.5, 3'ish and almost 5 yo), an adult female and an adult male (which are basically the same). Note the progressive shortening of the toe proportion (or elongation of the heel) and the forward'ish rotation of the big toe in relation to it's own axis compared to the other toes. Like I said, that aspect is exagerated in these shots but I'd guess would range from about 9:30 to 11 if we use the clockface analogy.

What does it all mean? Maybe bigfeet are just REALLY old gorillas whose big toes have migrated all the way forward? :wink:

Apeman

Dr. Meldrum;

Have you run any tests to see what kind of tracks are made by a man striding or running while wearing fake flexible prosthetic feet? Specifically, what kind of pressure ridges, if any, such a fake foot could make?

BipedC,


Don't get me wrong, not only at one time did think such a study would be interesting to have, but I actually gave some serious thought on doing this work myself. As I actually started to ponder the "nuts and bolts" of such an undertaking, I began to realize the limitations of what I could really ascertain. I really never proceeded beyond that for the following reasons:

1- The limitations on what I would be able to conclude providing I could obtain a decent amount of good core samples from alleged sasquatch tracks and the undeformed substrates they were deposited in. Long story short: After contemplating all the varibles, the only things I felt such an endeavor could conclude were if the print was indeed caused by compression(as opposed to digging the track out). Some very general thoughts could also be offered up on the minimum composite total of force necessary to cause the deformation that was present. I felt little could be concluded about mass of what left the tracks from these generalizations since mass is only one component of force(and not neccesarily the most important one, in a situation surrounding the very dynamic type of deformation likely caused by a sasquatch foot.)

2-How long it would take to get a decent sample size of data. At the time I was interested in pursuing this, Krantz was only adding a cast or two to his collection on a good year. Most Bf'ers are well qualified and know how to make castings and have the materials needed to do that. Castings can be copied long after they were originally made. Soil samplings for compression data requires the use of some fairly simple but very specialized equipment, not readily availible to most people that would have access to the prints in situ.

I can't figure out how to use the quote function to manipulate multiple quotes in a single post, so read between your lines for some comments:

"Still, even with the extensive "calculator gymnastics" I can't help but think that the end result of displacing "x" amount of "y" type of soil, is the summation of "z" total applied downward force."

Unfortunately, I can't see it being this simple due to the variables involved in the composite resolution of all forces involved and the rather dynamic nature that those forces are applied in something like the sasquatch foot. Soil really doesn't discriminate on how it's deformed. Again the variables would be enormous, and in all likelyhood the potential for unintentionally excluding some of those variables would be high. You would also eventually have to make some assumptions on what other factors other than mass (i.e. weight) are contributing to the force vectors that caused the resultant deformation. Just some examples: As the purported bipedal trackmaker speeds up/slows down, not only is it imparting changes to the magnitude of the total force vectors applied as it reacts with the substrate, but also it's altering periods of dual vs singular support. You'd have to make some assumptions if and when and to what magnitude this was happening.


"I also think that the apparent "flexibility" and "load spreading" characteristics of the Sasquatch foot model would tend to average the load distribution, thereby making "weight" (force x area) easier to calculate."

The problem here is that weight is a component of the force vectors but neither weight nor total force are at all dependant on the surface area over which the force is applied.

"It seems to me that the very "flatness" of alleged Sasquatch prints is a clear demonstration of "load averaging". If the load distribution uniformity of the foot was low or non-linear in nature, then accordingly there should be much greater variation in soil compression, - but this does not seem to be the case."

Again, I wouldn't be so quick to arrive at these conclusions. To a large degree your premise may be correct per individual track. Again the problem arises in trying to determine how much of the force causing the deformation can be attributed to mass. For instance if you take a person(of known mass) walking at 4mph and compare the deformation he/she is causing in a known substrate, to the same person traversing the same substrate at a higher rate of travel those results are going to be different, providing they aren't compressing the substrate completely at 4mph. Yet, the compression present at the higher rate of travel may exceed that caused by the same person traveling at 4mph while carrying a significant load to increase their respective mass. Again, how does one go about ascertaining how much of the resultant force vectors are caused by mass and not other contributing factors?


"Maybe the way to go about this is by applying foot models under varying loads to a standard "soil" in a laboratory setting. Once a "foot dynamics" model has been developed using this approach, variations in dynamics can then be taken into account in field settings, provided a reasonably accurate soil compression factor can be measured."

Soil compression can be measured with absolute certianty regardless of the dynamics involved in how the deformation was caused. This is simply a matter of collecting a compressed sample, cooking the moisture out of it and comparing it's dry density to that of an of an uncompressed sample of the same substrate. Even if one were to develop a good "walking model" the dynamic variables involved that influence the force vectors are eventually going to cause you to assume the sample was indeed collected under conditions that are consistant enough with your model(s) to even determine a very loose conclusion about the mass of what may have caused the deformation.

Again, I think your question is a good one, and one that I had a decade or so ago. As I thought about attempting to develop this, I realized that any definitive conclusions I could draw on the mass of whatever left the tracks via compression analyis, would simply be bad science.

Thanks for the feedback WillinYC, I'll take your word for it since math isn't my strong suit.

Just seemed to me that there was some potentially valuable data going to waste.

Biped,

I wouldn't really look at it as potentially wasted data. Even though there's severe limitations on what conclusions can be drawn from the data, I think the data may have value indirectly. Eventually one of the scientists involved in the bigfoot subject will write a paper or dedicate a chapter of a book to the subject of drawing correlations between the depth of purported bigfoot tracks and the respective mass of the the purported track maker. Eventually one of those scientists will ask the same questions you did, delve further into the variables involved, take the time to educate themselves and conduct experiments to realize the limitations. Although their conclusions probably won't be definitive to any degree, it wouldn't be that hard to at least improve on the efforts made thus far on the subject.

Interesting. I agree that using a tire as an analogy is valid to explain why bigfoot footprints may be deeper than would be expected using a simple calculation of the "flat foot." I have used this analogy for years though I am not sure I ever wrote it down before (except in my own notes). If you look at a tire track, it is obviously flat. Yet it was not created with a flat tire; presumably it was round. Bigfoot leave a flat print but I think it would be more appropriate to say they have flexible feet rather than flat feet. They may be called "flat" relative to humans in that they do not have an arch. To figure out the weight of a car you cannot go back and calculate the surface area of the tire track. What is the surface area of the tire track. Obviously it may be many miles long. Similarly, trying to calculate the weight of a bigfoot with a flexible foot may be impossible. So as WillinYC pointed out, think only of the portion of the tire that is impacting the ground at any given time. As the tire rolls along the force of every tread is eventually pushed relatively equally into the ground. The result is a flat track. The force moves forward on the tire as it theoretically does on the bigfoot foot as it rolls through the step. This may be one reason why the prints seem deeper than the expected weight should distort the ground with a known surface area.

Jim,

I think you explained that a lot better than I did, especially in respect to depth of impression vs. mass of print maker. In retrospect, my explanation was probably as "clear as mud" to most. Just to further clarify to anyone who's still wondering about what we're speculating about, I don't think either of us are suggesting that the purported sasquatch foot hits the ground incrementally like a tire. Simply that the force applied to such a foot is probably best viewed as being resolved along an incremental band that moves from front to back more so than in the human condition.

Also, in retrospect I probably should have mentioned that the range over which most soils deform plastically is a small one. Most people probably assume that if you apply a force of given magnitude to a known area of support on an undeformed soil sample, that doubling the magnitude of the force will result in a similar increase in the deformation(i.e. compression).
This really isn't the case. Individual soil particles in a homogenous substrate do tend to be roughly the same size, but are not uniform in shape. The individual particles are in contact with one another, but there is a latticework of interstitial void spaces surrounding each particle. When a soil is "compressed" , the actual individual particles don't get compressed, but simply the void spaces surrounding those particles become smaller. As those void spaces become smaller, the force required to cause futher compression, increases in a nonlinear relationship. When the void spaces are gone, increasing the force several times over is simply not going to cause any significant increase in deformation.

I think any conclusions being drawn about the apparent "flatness" of sasquatch foot anatomy from any prints thought to be real need to consider the very distinct possibility that the percieved "flatness" can actually be a factor limited by the substrate(providing the foot that left it whether it's a real foot or a fabrication, isn't rigid and is itself subject to deformation). As that substrate approaches it's compression limits.

It worked like a charm. I just preordered my copy from Amazon.com. :closedeyes:

My gawd, what a wonderful thread. This is what the BFF is all about, IMO. Great job you peeps! :new_thumbsupsmileyanim:

I am humbled to be able to sit here and read and learn from Dr.Meldrum, awesome, can't wait for the book!

i'm late to the party but can I say wow? wow

Maybe we can revive the party. I'll second your "wow".

Since I was still skeptical that Dr. Meldrum’s foot could easily make the track shown in the Laverty photo, I decided to use a photo produced by Dr. Meldrum as a model to show how its foot should theoretically deform the ground and I did my best to be fair and open minded. To show where the joints flex, the first frame in the animation shows how I broke up the picture. I modified it by providing flexibility at the transverse tarsal joint (aka mid-tarsal break (MTB)), and the metatarso-phalangeal (MTP) (toe) joint. I also used a photo of the side view of the Laverty print from Colobus’s previous post, cut the edge of the cast surface, and pasted it on the last frame of the animation to create a relatively accurate cross section of the print. Somewhat to my surprise, I was able to create a relatively fluid and natural movement and so I thought I would share my animation. It is not a perfect replication, the movements are crude, and deformation of soil is guestimated. Dr. Meldrum’s comment regarding an eye witness suggesting a curved foot also seems to fit the recreation. I would like to point out that flexibility at the Tarsal metatarsal joint (TMT) joint, and shortening the metatarsals and increasing the ankle bones as I had suggested should also be able to form the track. I still prefer my larger ankle bones and shorter metatarsal. Still, in my opinion, there is more agreement than disagreement. Essentially, the ridge in this recreation seems to be created by Patty pushing downward harder on the later part of her step. I suspect if this step were more fluid, it would have ended in a flatter more typical print. To see the animation, I believe you need to click on the thumbnail photo below.

As animals grow larger, they generally should adapt with thicker bones, larger proportionate feet, or shorter bones to deal with the greater stresses associated with increased size unless there are mitigating factors providing a good reason for long foot bones. With bigfoot, perhaps their toes are relatively long to help provide more propulsion when it swims. Some of the fastest swimmers have big feet and putting on flippers obviously greatly increases swimming ability. I think there is pretty good evidence that bigfoot are comfortable in the water and possibly even semi-aquatic. Some of the stories from Alaska especially support this aspect of their behavior. Green also noted that nearly all sightings were near major bodies of water. I remember hearing about some footprints displaying what appears to be webbing though I cannot claim any personal knowledge about this particular characteristic.

Another thing that seems to lend some credence to the long toes in Dr. Meldrum’s reconstruction, is the Yeti foot print from Shipton’s famous photo, assuming it was not faked. It shows one very large but short big toe, one very long middle toe and three small toes which seem to operate together. The length of the middle toe seems to provide evidence that long toes are not necessarily maladaptive.

Yet I was/am still skeptical. The double ball seen on Primateer’s enhanced photo seems like it would not function correctly for a foot that dorsiflexes (the motion of opening the fist (or raising the toes)) as opposed to plantarflexing (the motion of making a fist). The human hand and a chimp’s foot obviously work well in plantarflexing. A chimp can grab a branch with a foot in a similar way that a human does with its hand. Yet the human foot functions primarily in dorsiflexing. The human foot has a pad (not split) behind the big toe at the ball. It is not split in my opinion because it operates in plantarflexion and if the pad were split, there would be an exposed spot between the pads that would be more susceptible to injury because it would be unprotected by a pad. Patty's double b*lls seems to be relatively widely separated. I think Patty probably typically walks with plantarfelxion as shown in the animation and in a manner similar to humans and the main stresses should be in similar areas to ours. I am skeptical that the ball pad would split for a creature with foot functioning primarily in plantarflexion unless there are separate joints. It is a somewhat difficult concept to convey and I hope I didn’t butcher any of the technical terms. Anyway, hopefully someone can provide a explanation for the separated double b*lls.

Nice work Jim.

The double ball thing is a puzzler. I'm not convinced of its frequency outside of the bluff creek area. It seems to be one of those items that's hard to get a handle on. Much like the old one - is there such a thing as an "hourglass" shaped track? Or is it a regular track merely impressed into a harder substrate?

Anyway... a few days ago I posted something in another thread that you might find interesting, as it has tangential relation to this thread. It's something I brought up with Jeff some months ago, and so I thought I'd let you test drive the ideas a bit. Again, nice work.

...."Your post brings up an interesting point however. That is the change in angle seen in these putative MT Breaks in various trackways, and within the same trackway, and why MT Breaks are apparently only occur some of the time.

Based on analysis I've done over the last seven months or so (some of it original data collection, and some review of previously collected data) I think I MAY have found out why this appears to be so, and under what conditions MT Breaks can occur.

Basically I've come to the conclusion that the MT Break - that is the physical evidence of the flexion of the transverse tarsal joint - is not solely due to midfoot flexibility, but also corresponds to the passage of the other leg (contralateral limb) in the swing phase, and the resulting shifting of weight distribution on the joint, AND the cadence.

These conditions appear to all be met only between certain rates of movement. Prior to that initiating rate, and after the maximum rate is exceeded, the MT Break is not appreciably present. It is also possible that arm swing beginning or ending may be coincident. As far as what those rates are I'd have to say somewhat slower than Medium (where medium = cruising speed). Very subjective I know.

As far as the angle of the Break itself within the track, that appears to have a fairly simple explanation. While the MT Break is postulated as being the physical evidence of midfoot flexibility, it does not exactly mirror the angle of the transverse tarsal joint, merely it's position (It is a position along the length of the foot where flexion occurs and the sheer forces act upon the substrate).

Back to the angle business. As people who are observant doubtless know, the angle of Toe Out, and the changing straddle, both change with cadence. As one begins to walk the Toe Out is greatest, momentum is lowest, and armswing (which also acts in stabilization) may or may not be present. Increase speed and at some point the arms will begin swinging (if they have not already). As the cadence increases, angle of Toe Out is reduced in both feet, as is the straddle. Increase speed enough and straddle all but disappears, and the Toe Out is virtually zero - the foot is parallel to the direction of travel. Almost there.

These observations about Toe Out and straddle appear consistent with putative sasquatch trackways. While the centerline position of the MT Break left in the track marks the transverse tarsal joint, the angle appears to be always perpendicular to the direction of travel (and sheer force)(and possibly GRFV). So within that window of speeds at which the MT Break may occur, there are a variety of Toe Out angles, and thus varying angles of the MT Break as expressed in the track floor.

Most people have an idea of the "Classic" sasquatch trackway, and most of those candidate trackways have a Toe Out angle that is low, and very little straddle, and a very long step. In other words ... trackway maker was going at a good clip making a bee line for somewhere. But when an individual animal is just starting walking, or moving slowly looking from side to side, the trackway has noticeable straddle (because at lower rates of speed there is less stability) and the Toe Out angle is greater (for the same reason of stability)."

As I was reading the information in your post (which is very interesting) I started thinking about foot size and also talocural (ankle) joint location in relation to body weight, muscle mass, and bone density. For example, in the Draft horse breeds the hoof is much larger in proportion to the size of the body then in light horse breeds, not because of the greater height of the horse (because many light horse breeds such as the Thoroughbred are often as tall as a Draft horse) but due to the greatly increased muscle mass and higher bone density (ie: weight) the weight bearing surfaces on the Draft have to carry. Draft foals are not born with hooves that are proportionally any larger then those found in foals of light horse breeds since they are not yet carrying the increased body weight (see example below). Also, in order to compensate for the greater body weight fully grown Draft horses also usually have less of an angle to the hock and fetlock joints with these articulating slightly forward then in lighter breeds. My point being that following the same weight (not height) to foot size ratio is it safe to assume that this would also be true when estimating the height of a full grown Sasquatch by studying the print size when there is no data on print depth? More specifically, considering the weight to "foot" size ratio above is it safe to assume that a full grown Sasquatch would not be as tall as a human being with the same size print due to the increased muscle mass?



Click to view attachment

I am just blown away by the knowledge expressed in this thread. I'm very impressed by the research that the posters have done concerning this subject.

:bffrules:

I would wonder if Dr. Meldrum could take a few minutes once a month or so and address some of the subjects that come up in this field. It would be greatly appreciated.

I agree and there is some evidence to back it up. For example Patty's height is 5.5 times her foot length assuming a foot of 14.5 inches and 80 inch height (slightly stretched). Both my wife and I are 7 times our foot length in height. So if I kept my proportions but grew into Patty's foot length, I would be 14.5 inches X 7 or 101.5 inches tall (8.5 feet). Wow, much taller than I expected. Patty has a very large foot compared to my wife and me. As a animal gets taller yet maintains the same proportions, its volume (weight) increases in 3 dimensions, whereas cross-sectional area of the ankle bone (for example) only increases in two dimensions. This necessitates a proportionately bigger foot for a draft horse or presumably Patty IMO.

Very interesting conclusions. I hope you don’t mind me thinking out loud a bit as I respond. I think it likely that the prints with the deepened forefoot occur when there is a deviation in their step from uneven terrain, or from some behavior that the Sasquatch is exhibiting. Do we know which frame in the film the Laverty print corresponds to (if any) and can we tell what Patty was doing at that particular step? i.e. was she looking back at Patterson? Was it one of her first steps after seeing P&G.


I suspect that you are correct. She has probably shifted the maximum weight on that foot. It has been shown that she keeps both feet on the ground an unusually long time and perhaps if she steps out a little further with the other leg, she is more likely to create a print with the forefoot more deeply imbedded in the substrate because she would be forced to put more weight on it at that point in the step.



Presumably after the animal gets to speed, its cadence will be more fluid. It makes sense to me that there would be flatter prints after it reached a good speed. In starting up, it might need to “dig in” a little to adequately accelerate. As a young child, I remember hearing stories that seemed true to me, that the Lakota (Sioux) were taught to walk with their toes slightly inward or straight, presumably to increase their walking efficiency. I would always try to achieve this also when hiking. The idea is have your big toes in a line with your feet pretty straight. To deviate from this, you would waste some energy in rotational forces if I understand it correctly (I didn’t think of that as a kid though). For me, bigfoot walking in a straight line with low Toe out angle makes a lot of sense as they seem to achieve the Lakota ideal.



I am still not convinced that you can definitively mark the transverse tarsal by measuring the print because if my animation is at all accurate, it involves a sloped curved sole surface with a thick pad. I think the margin for error there is pretty great.

I think you have a good theory explaining the varying angles of the ridge. If the foot had a large toe out angle during one of the initial steps, I would expect the ridge to still be perpendicular to her route as you suggested because her angled foot is pushing backward in the opposite direction of travel and thus resulting in a slightly different ridge angle on the footprint. I think a thick pliable pad would also tend to help form a ridge perpendicular to the force.