Bigfoot, an evolutionary argument for it's non-existence.

[Just thinking]

And what's with that foot? I mean, what is up with that?

It says, "Look at me, I'm shaped like a biped foot, but I have have a mid-tarsal break like a gorilla, and an underdeveloped achilles tendon"

I mean can someone please help me out with that?

Could be worse ... could look like this.

 

[William Parcher]

In the new NatGeo program at 16:30, Meldrum proposes that Gigantopithecus was bipedal. It was up to 10' tall and up to 1200 lbs. The narrator mentions that "most scientists agree that Gigantopithecus was a quadruped. Though some say it could only have carried its bulk one way." Then Meldrum says that "nearly 1000 lbs." is too heavy for a knuckle-walking primate. The compressive stresses would be too much for the shoulders and it wouldn't be efficient or effective. This problem would be solved if the weight was carried by the legs... bipedally.

 

[The Shrike]

Then Meldrum says that "nearly 1000 lbs." is too heavy for a knuckle-walking primate. The compressive stresses would be too much for the shoulders and it wouldn't be efficient or effective. This problem would be solved if the weight was carried by the legs... bipedally.

Good heavens, it's sounding like time for an intervention.

 

[Drewbot]

Here we have a fossilized knuckle walking primate weighing over a thousand pounds, however, this does not mean that a knuckle walker could weigh that much.

I wonder if he is thinking of brachiating, '1000 lbs is too heavy for swinging in trees'. could he make that mistake?

 

[William Parcher]

I don't understand your post, Drew.

 

[DennyT]

Quadrupeds would have trouble walking their pets.

 

[Drewbot]

I don't understand your post, Drew.

sat the first paragraph in Dr Meldrums voice and think about how silly it is

 

[William Parcher]

sat the first paragraph in Dr Meldrums voice and think about how silly it is

You wrote something that Meldrum would never say. Whether you think he is wrong or not; he doesn't actually contradict himself.

 

[DennyT]

Good heavens, it's sounding like time for an interventiohttp://www.csmonitor.com/2003/0604/p01s02-usju.htmln.

Meldrum seems to be looking at evolution through a keyhole and in reverse. He starts with the idea that Bigfoot exists and therefore Bigfoot makes sense in an evolutionary sense, then tries to make everything fit. It's a hard job but it pays well.

 

[Drewbot]

You wrote something that Meldrum would never say. Whether you think he is wrong or not; he doesn't actually contradict himself.

You say that he said this a few posts ago

Then Meldrum says that "nearly 1000 lbs." is too heavy for a knuckle-walking primate.

And on page 99 of LMS by Dr. Jeff Meldrum, he says:

Given Gigantopithicus's large size, activity in the treetops was virtually prohibited, and tropical fruits out of reach. It was most likely ground-dwelling, or terrestrial. Once restricted to the ground by it's bulk, there would be only two locomotor options- either quadrupedalism (including a possible form of knucklewalking or perhaps fist-walking) or bipedalism.

So, if he said that 1st quote in the program, he is clearly contradicting himself.

And my statement;

Here we have a fossilized knuckle walking primate weighing over a thousand pounds, however, this does not mean that a knuckle walker could weigh that much.

simply highlights that contradiction in a mocking way.

We have a fossil of a 1000 lb knucklewalking primate, yet it couldn't be knuckle walking, even though Meldrum has said it could be knucklewalking.


I think you are misapplying your

he doesn't actually contradict himself.

claim.

If he MEANT to say "To big to be a brachiator", then that would match up with his claim in the book. (see above LMS quote)

 

[William Parcher]

Drew, I think you've created another strawman argument by misrepresenting what Meldrum is saying.

Given Gigantopithicus's large size, activity in the treetops was virtually prohibited, and tropical fruits out of reach. It was most likely ground-dwelling, or terrestrial. Once restricted to the ground by it's bulk, there would be only two locomotor options- either quadrupedalism (including a possible form of knucklewalking or perhaps fist-walking) or bipedalism.

He's saying that a ground-dwelling primate has only two options for locomotion.

1. Quadrupedalism
2. Bipedalism

But he says that option 1 is not available to Gigantopithecus because it's too heavy.

I could make a similar example with a bird...

An extinct ground-dwelling bird such as the Dodo (Raphus) has only two options for locomotion.

1. Quadrupedalism
2. Bipedalism

Option 1 is not available to the Dodo because its wings cannot be used as front legs.

 

[Correa Neto]

Meldrum's claims regarding gigantopithecus weight x bipedalism or quadrupedalism can be tested in two ways.

1. Paleontologists use software to simulate dinosaur locomotion modes and how much weight could their bones resist. So, test possible skeleton models to see if they would resist the weight. One could get a maximum limit for the weight of knuckle-walkers, for example.

2. Check the fossil register. Are there any knucle-walking critters as big or larger than gigantopithecus? The answer is- YES. Chalicotheres.

So, I believe (2) is a good indication that he's most likely wrong.

In theory, sustaining a given weight with four collumns (quadrupedal or knuckle-walker) should be easier than with two (bipedal). Its a mere question of weight distribution. But if the four collumns are poorly projected...

 

[William Parcher]

2. Check the fossil register. Are there any knucle-walking critters as big or larger than gigantopithecus? The answer is- YES. Chalicotheres.

Estimated weight for Chalicotheres are up to 772 lbs (350 kg).

 

[LTC8K6]

Those ground sloths were pretty big and I think they knuckle-walked.

Also, with the posture of knuckle walkers, isn't the weight shifted rearwards? That way they can rise up on their hind legs easier to reach things.

 

[Drewbot]

Those ground sloths were pretty big and I think they knuckle-walked.

Also, with the posture of knuckle walkers, isn't the weight shifted rearwards? That way they can rise up on their hind legs easier to reach things.

I can find nothing in the journals about the weight limits of knuckle walking.

I wonder if that is a personal theory. He needs Giganto to be a biped now.

 

[The Shrike]

Some good stuff in attached paper. A case can be made that some large ground sloths were capable of knuckle-walking, but it was quite different than that which we see in apes today. Of course, orangs don't walk like gorillas either, so there's probably a lot more locomotory (locomotive?) plasticity than we generally appreciate even in the Primates.

But all Meldrum needs is one reference stating that Megatherium was at least occasionally bipedal and he can say "See? Really big animals can be bipedal."


PS: PDF I wanted to attach was too big. Check out Bargo et al. 2000 from the Journal of Vertebrate Paleontology. LIMB BONE PROPORTIONS, STRENGTH AND DIGGING IN SOME LUJANIAN (LATE PLEISTOCENE-EARLY HOLOCENE) MYLODONTID GROUND SLOTHS (MAMMALIA, XENARTHRA)

ABSTRACT—The mylodontid ground sloths (Xenarthra, Tardigrada) are among the most intriguing components of the Lujanian (Late Pleistocene-Early Holocene) fauna of the Pampean region in South America. Limb proportions and resistance to bending forces were studied in Scelidotherium, Glossotherium and Lestodon to infer their locomotory abilities. Body masses were estimated using scale and computer-generated geometric models. Allometric equations were calculated from humeri, ulnae, radii, femora, tibiae, and the pes, and were used to predict linear dimensions from body mass. Slopes and intercepts were obtained using Model I and II regressions. An indicator of strength was calculated for humeri and femora. Body masses of approximately 850, 1,500 and 4,100 kg were estimated from scale models for Scelidotherium, Glossotherium and Lestodon, respectively. The proportions and capacity to resist bending forces of the limb bones of Scelidotherium and Glossotherium indicate that they were well adapted for strenuous activities in which force is enhanced over velocity, such as digging. We consider these taxa as possible builders of the large Late Cenozoic burrows present in the Pampean region. Although limb proportions of Lestodon are comparable to those of the others, its low strength indicator suggests that its limbs were not as well designed to perform such strenuous activity.

 

[William Parcher]

Ground sloths walked on the side of the "hand", not the knuckles. There may be evidence that they were bipedal.

Several South American ground sloth fossils were studied for the possible functioning of the limbs (Vizcaíno et al 2008)...

* Researchers using trackways and biomechanical calculations said Megatherium americanum and some mylodontid sloths could walk upright (were bipedal).

* If ground sloths were bipedal, then arms were free for other tasks such as digging and/or defense.

* Farina and Blanco (1996) suggested Megatherium arms and claws weren't used for digging, but instead were capable of fast, aggressive action perhaps in defense.

* By contrast with Megatherium, two mylodontid sloths analyzed seemed to be very well suited for powerful digging and they may have produced burrows seen in Pleistocene sediments exposed along sea cliffs in Argentina. (Vizcaíno et al 2001)

 

[William Parcher]

(Ground sloth) Feet are twisted inward when walking ( McDonald 1977).

 

[Drewbot]

Has anyone found anything about the weight limits of a knuckle walking ape? Is Meldrum talking out of his derriere when he says Giganto couldn't be a knucklewalker because it is too big?

The ground sloth could obviously walk on it's hands, and got huge, but do we have anything
about the limits of a gorilla or a giant ape that couldn't walk on it's knuckles?

 

[Correa Neto]

Estimated weight for Chalicotheres are up to 772 lbs (350 kg).

Heck, 350kg would enough to make a HUGE primate IMHO...

Now, if the animal walks over knuckles, feet straight or twisted, well, I think its not a big issue regarding the OP. The question is if huge primates can be bipedal or not.

It seems a quadrupedal locomotion is a good option. I suppose the forelimbs can supported by knuckles or twisted or straight feet. Its a matter of adaptation.

A similar argument could be raised for bipedal. Solid columnar legs could evolve to support such a beast. The question becomes - how much would these would compare to the most common bigfoot renderings?