Talk:Bipedalism

Tool Use
RPG Hamaca — Preceding unsigned comment added by 123.243.10.202 (talk) 11:19, 10 June 2015 (UTC) There's an unattributed line about tool use leading to bipedalism, which seems odd considering some pre-australopithecines were bipedal, and yet tool use is completely unevidenced before A. garhi. Can we just delete this?

Support removal
It is absurd that the AAH gets so much attention on this page, when it's a main article for an important concept in paleoanthropology and animal evolution. In any case, I support this removal of Algis' work. He's hardly a big name in anthropology, and is a primary source discussing a single experiment. Wikipedia should be based on secondary sources - review articles and the like - making this inclusion inappropriate particularly when there are better sources from more reputable authors (who haven't tried to spam the idea across wikipedia). WLU (t) (c) Wikipedia's rules: simple/complex 14:11, 21 March 2010 (UTC)


 * Actually, I disagree about primary sources; I feel they should be used whenever possible in preference to secondary sources, as a lot of secondary sources are obsolete, mistaken, or just plain wrong. It's just that this particular one didn't actually support the claims being made. Mokele (talk) 16:25, 21 March 2010 (UTC)


 * However, your initial sentence made me think - I'm not really familiar with any work on why, exactly, dinosaurs became bipedal in the first place (either theropods or the later ornithishcians), nor the few bipedal crurotarsans. I'll have a look around the primary literature, but it's an interesting problem.  It's occurred multiple times, but only in this one lineage, with the only real exception being humans.  I'll ask some of the paleo folks I know. Mokele (talk) 16:25, 21 March 2010 (UTC)
 * The advantage of primary sources in terms of being less obsolete is only really meaningful in a short timespan, and are themselves vulnerable to being obsolete, are more vulnerable to being mistaken or wrong (because with a 95% certainty, 1 in 20 experiments will be wrong) and are far, far more vulnerable to being cherry-picked to support a tenuous conclusion. Not to mention the fact that in most cases you have to do some original research to get them to say anything useful in a lot of pages, and per WP:PSTS we're supposed to use them.  That's a general comment, regards the AAH the whole idea is bad since it's not a serious theory anyway (and SYNTH and UNDUE both support it being bad to use primary source to buttress the material).  The only reason there is any extra material in that section is because it is unfair to portray paleoanthropology research as depicting humans never interacting with water, or ignoring it.  Still tenuous though.
 * I do agree that the page needs more focus on nonhuman bipedalism and bipedalism as an evolutionary strategy in general - all this focus on the AAH, the tendentious editing from AAH boosters, is a distraction from the actual purpose of the page - a discussion of how bipedalism has evolved and why. WLU (t) (c) Wikipedia's rules: simple/complex 17:01, 21 March 2010 (UTC)
 * I can see there is no point trying to argue against biased people like "WLU" who have hijacked any page which might give Hardy's idea a little credit. WLU's determination to keep waterside hypotheses in the same "crazy box" as Von Daniken and creationism seems to have no end but in the end it demonstrates an alarming lack of the power of discrimination. I will not try to edit this page any more but I think it is a very disappointing that the ignorant sheep mentality against this idea even denies papers published in peer reviewed journals any credibility. The fact that I am not a "big name" in anthropology is neither here nor there. It is a good paper which made some important points on human bipedal origins. The "AAH", as you keep referring to it, is a misnomer. The "aquatic ape" was meant to be an ironic label. It's an irony that anthropologists, amazingly, have never understood. Rather than rolling their eyes at the prospect of "primate seals" or "mermaids" perhaps they should have spent a moment considering if moving through water could have caused sufficient selection to make a difference to our evolution. The fact that all apes switch from quadrupedal locomotion to bipedal locomotion (not just posing momentarily) when they find themselves in waist deep water is about the most compelling evidence imaginable for a model of bipedal origins - and people like WLU dismiss it out of hand. Shocking. AlgisKuliukas (talk) 13:48, 26 August 2010 (UTC)
 * When you can cite a large number of peer-reviewed sources that demonstrate support for the theory, so you are no longer promoting a pet theory, then the page can change. In the meantime it's undue weight on a minor theory that's not really a big player in the field.  No original research, no advocacy, no promoting your own work.  Them's the rules.  WLU (t) (c) Wikipedia's rules: simple/complex 00:33, 29 August 2010 (UTC)

"Aquatic ape hypothesis" changed to "Wading models"
I made this change because AAH is not the only hypothesis that talks about wading bipedalism. Wrangham, Cunnane and Niemitz are professionals in their own fields, their theories have good evidences and are only loosely related to AAH. Niemitz even rejects AAH, grouping him with it is unfair to him. Even if AAH is to be debunked as a whole, the plausibility of these wading models should not be affected. (BTW, wading in shallow water is a *terrestrial* locomotion, not aquatic/semi-aquatic.)

You may object my editing using UNDUE, but please look at other models. Many of them are discredited (e.g. stone tool carrying -- wrong evolutionary time) or unconvincing on key assumptions (e.g. monogamy in provisioning model). Even the thermoregulatory model (in fact one of my favorite theory) also lose ground becuase Ardi & Lucy didn't live on a hot dry grassland (so it isn't the initial stimulus = isn't the origin). These hypotheses are out-dated but still enjoy "full coverage", there's no reason why only water-related ideas have coverage reduced (I don't suggest to reduce those out-dated hypotheses, they're important historical ideas). Chakazul (talk) 17:48, 25 March 2010 (UTC)
 * Not a bad change, but an even more generic title might be better. WLU (t) (c) Wikipedia's rules: simple/complex 00:33, 26 March 2010 (UTC)
 * May I suggest:


 * The influence of water is more than just the AAH; though it is significant because of its popular appeal, it has no real research support or acceptance. But real theorists publishing in serious journals have proposed the influence of water making the AAH a bit of a sideshow and detracting from the serious scholarly attention which does exist for a small number of researchers. WLU (t) (c) Wikipedia's rules: simple/complex 00:46, 26 March 2010 (UTC)


 * Your choice of "Influence of water" is not bad too, but I suggest "Wading models" with some reasons. (1) It's the common theme of those hypotheses (Niemitz: wading, Cunnane: wading for nutrients, Wrangham: wading for fallback foods), and "influence of water" may mean drinking/using/splashing of water, not specific to wading. (2) It's a parallel to other categories e.g. "carrying models" -- it actually consists of competing hypothesis like carrying infant/carrying food/carrying tools, and those authors won't say that they belong to a bunch of "carrying models". Similar for "wading models", it's just a convenient term.


 * Why I say they're independant studies -- Cunnane is sympathetic to AAH, but his main thesis (diet and brain) is well supported by hard evidences, his idea on bipedalism is just a logical extension to it. Wrangham (primatologist) started research on bipedalism *before* the existence of AAH (e.g. Wrangham 1980 "Bipedal locomotion as a feeding adaptation in gelada baboons and its implication for hominid evolution"), and he didn't mention AAH in the thesis -- no need to. Niemitz mentioned AAH, but rejects it: "[AAH] did neither fulfil the criteria of a hypothesis nor of a theory" (in ref). If these researchers reached similar conclusions from different starting points, using purely scientific methods, then it *is* science. Lumping them with AAH is a kind of fallacy: if they look similar, then they must be in the same gang.


 * Now I treat your suggestion seriously: (1) There's no need to elaborate everything about AAH here, it's dealed in its own article. (2) Please provide reference support for your claims: "it (you mean the influence of water?) has no real research support or acceptance" and "real theorists publishing in serious journals... making the AAH a bit of a sideshow and detracting from the serious scholarly attention". Without proper support, these statements sound like personal opinions or conspiracy theory. Chakazul (talk) 05:26, 26 March 2010 (UTC)


 * Mokele: I've reverted your undo. Reasons are given for my change, please give your reasons before you make the rollback. Chakazul (talk) 05:36, 26 March 2010 (UTC)
 * The AAH proposes a much stronger interaction than "wading", and only the AAH see water as a primary driver of evolution while the other models see water as one factor with small impact. You may have mistakenly thought that my entire entry was proposed for inclusion.  It was not.  Only what is in the blue box is what I propose, and it uses essentially the same text as is currently available with only a bit more elaboration - sources are the same as the current version.  Water is still not seen as the primary driver of evolution within paleoanthropology, even if it is seen as having some influence.  Any section should be short since aquatic adaptations are still well-shy of the theory of human bipedalism.  There needs to be multiple, convergent, mainstream sources pointing to the same idea - water had a strong influence on human bipedalism.  I don't believe they are there, even if you can pick out from the thousands of papers published every month, a couple that propose some push from water.  I've reverted your revert - discuss first, then lets paste a consensus version.  WLU (t) (c) Wikipedia's rules: simple/complex 10:37, 26 March 2010 (UTC)


 * I feel strange that my entire editing is reverted a few times, in that it's neither vandalism nor unsupported information. Is there a WP rule that someone can/should guard the article like a police? Well, anyway, let's discuss.


 * I suggest to use your first paragraph, because it does tell the truth about AAH. Readers will know about it and also aware of its current reception. How about use my sentences on Cunnane, Wrangham and Niemitz? It's useful to let readers know the existence of these models. Provided that the paragraph is not too elaborated, WP is a good starting point for deeper digs. "Wading models" would be a better title, because this article is not about AAH (only it puts more importance on water). Despite all AAH's other claims, only its "wading bipedalism" component is relevent here, and in fact the least controversial aspect of it.


 * So my suggestion looks like


 * Removed "small but significant" -- a bit ambiguous, and the authors don't claim that the pressure is small. Chakazul (talk) 07:46, 28 March 2010 (UTC)

The entire last sentence of the first paragraph is pretty suspect - there's certainly no way to claim it's had "the most" public interest, and the length of time an idea has been around means absolutely nothing. It also notably lacks any strong note about *why* AAH and wading theories are rejected (lack of evidence, rarity of aquatic movement of any type in modern apes, etc.). I also don't like the "name dropping" - I think it's unencyclopedic, and smacks of promoting names over ideas. Mokele (talk) 15:40, 28 March 2010 (UTC)


 * In fact the notions "human evolved in savannah" or "Man the Mighty Hunter" are even more popular, although they are now scientifically inaccurate, they still survive in school textbooks and popular memes.
 * We can say that AAH is not accepted by the mainstream, but the wading theories are in better situation. Even to the harshest criticizers of AAH (e.g. Jim Moore, Langdon, and many biologists/anthropologists), wading bipedalism as a stand-alone idea seems to be less criticized or ridiculed, presumably because it requires fewer radical assumptions, and it does happen in many apes/monkeys (they go biped when wading occasionally).
 * I don't mean to "name dropping" or hide AAH under another name (well that's the bad practice in creationism/ID), I just wish to be fair to the idea itself and to the scientists who do real researches.
 * Any more idea on my suggestion? Chakazul (talk) 17:27, 30 March 2010 (UTC)
 * P.S. Mokele: again, "lack of evidence" would not be a reason, or else all the carrying / behavioral / thermoregulatory models would be rejected already, due to their lack of any evidence. Chakazul (talk) 17:34, 30 March 2010 (UTC)


 * My point is that popular support should be omitted entirely - it's hard to assess and completely irrelevant. After all, there are *far* more people in the US who think humans were made from dirt by a magic sky pyxie than came from an ape, aquatic or otherwise.
 * I also don't like giving wading so much credit - it hasn't attracted much attention yet, period, whether positive or negative. Many of the publications are just a few years old, which, in scientific time, might as well be yesterday.  If you can cite a source AAH critics seeing wading as more palatable, great, but if not, a simple lack of response is not an endorsement.
 * As for "lack of evidence", we have plenty of evidence that modern apes of all sorts experience intense thermoregulatory demands, carry objects for great distances, etc. All we have for wading is a rarely observed activity (which AK's own paper shows occur only a tiny percentage of the time) of dubious selective pressure.
 * Re: "lack of evidence" -- I would like to know any real example of modern primates go bipedal because of thermoregulatory demands, or carry objects for long distances. But even there're examples, they can only be hints/analogies, not really evidences for the human condition. Chakazul (talk) 21:32, 5 April 2010 (UTC)
 * And names stay out. It's poor formatting, verges on argument by authority (presenting only one set of claims in the format of "A real live scientist found that blah blah blah"), distracting, and unencyclopedic.  We have references by number, just like Nature, and if it's good enough for Nature, it's good enough for WP. Mokele (talk) 19:14, 30 March 2010 (UTC)
 * I don't like the use of names either, bar Morgan simply because of her prominence re: the AAH and that she has a separate article. I don't really think any of the water-based theories deserve much discussion or even names - none of these are primary drivers of bipedalism theories, and have a very limited research base.  From what I know (and that's not much) the woodland mosaic is considered the primary driver and environment of the evolution of bipedalism.  Right now, as a recent review article Niemitz is the best source we have for human evolution related to water, but the "amphibian generalist theory" shows up exactly once in google scholar .  It deserves a mention, but hasn't yet revolutionized theorizing about bipedalism.  This article suggests simple energetic efficiency in locomotion is the primary driver of bipedalism, but it's difficult to find review articles using the search terms I can think of.
 * The failing of other sections in no way support having a low-quality aquatic adaptations section. They should be cleaned up or removed (as I did with the Savannah hypothesis).  WLU (t) (c) Wikipedia's rules: simple/complex 00:54, 1 April 2010 (UTC)


 * True that the relevent papers by Wrangham and Niemitz are not much cited in google scholar, but Cunnane's idea is more influential (2003 paper cited 61 times, 2005 book cited 23 times). I think Cunnane's name could be mentioned, may be not the other two.
 * Wading models are not quite influential or revolutionizing by now, but they're surely legitimate and plausible like others. They deserve a mention in this article, ignoring them will give a misundertanding that no such idea exists.
 * The only thing I insist is to change the section name, because these scholarly models are not weaker versions of AAH which propose an overall semi-aquatic life, while wading is still basically terrestrial (i.e. after the acquisition of bipedalism by wading, other features could still be acquired in inland scenarios). That's why Niemitz being an anthropologist could still have his wading papers published.
 * I agree to clean up other sections. Many of them lack citations, and some sound like personal opinions. Chakazul (talk) 21:32, 5 April 2010 (UTC)
 * I've made the changes, I hope the change is minimal. Chakazul (talk) 21:43, 5 April 2010 (UTC)

Persistence hunting
Can mention of Persistence hunting be made in this article? It seems like a good way to compare the advantages of bipedal motion, particularly in relation to the disadvantages of quadripedal running and it's effect on thermoregulation in animals that must pant. Roidroid (talk) 13:08, 13 December 2010 (UTC)

Morgan's Aquatic Ape
The section needs a simple statement informing readers about the absence of scientific standing for this "theory". If we remove that statement, then we need to remove Morgan's "theory" altogether, as per WP:UNDUE: "Generally, the views of tiny minorities should not be included at all, except perhaps in a "see also" to an article about those specific views. For example, the article on the Earth does not directly mention modern support for the Flat Earth concept, the view of a distinct minority; to do so would give undue weight to it." Morgan's "theory" is as credible as a flat earth "theory".

The problem here is one that has arisen in other articles, that the fringe belief has become popularised despite being held by no credible scientists. As a result it really should addressed in the article since it is clearly notable. But it can’t be simply added without comment because it is a fringe theory.Mark Marathon (talk) 02:33, 9 January 2014 (UTC)


 * Morgan’s promotion of the influence of wading on human bipedalism is the issue in this article, not her general theory the status of which is discussed in the AAH article. There is no consensus for removing reference to it, see above under "Aquatic ape hypothesis" changed to "Wading models". The claim sourced to  Meier that ("It is not accepted by or considered a serious theory within the anthropological scholarly community") belongs in that article not this one  though I note it is out of date with respect to her later work which has attracted renewed interest since the demise of the savannah hypothesis.  Your personal opinion of her work, which has been published, eg, in the New Scientist, or of its status in the scientific community as on a level with flat earth theory is uniformed prejudice. Almanacer (talk) 11:06, 11 January 2014 (UTC)

Increased capabilities of postural/locomotor neural control - new hypothesis
All quoted hypotheses do not address the issue of the appropriate control of the newly emerging posture. They take for granted the ability to control upright bipedal locomotion with additional trunk rotations and head, eye and forelimb movements. To perform locomotion and assume a certain posture, the basic condition (conditio sine qua non) is to ensure the stability of the body. In a recently published article: Significance of adequate postural control in the appearance of habitual upright bipedal locomotion, Sekulic et al. Medical Hypotheses 2012; 79: 564-71 new hypothesis was published. Analysis of qualitative indicators of stability of the body during different types of locomotion in primates suggests that bipedal locomotion is not variation of some other type of locomotion. Transition from quadrupedal to bipedal locomotion is accompanied by a qualitative difference in body stability. Because of assuming an upright bipedal posture, the center of mass is lifted, the surface of the base of support is reduced, and the body structure does not provide passive stability in relation to moments of force of the body around Y-axis (quadrupedal mammals already loosed stability provided by body construction around X and Z axis). Additional head movements, trunk rotations, forelimb manipulations with objects and surveying the surroundings are necessary for survival, but they increase the degree of freedom of movement and further complicate the task of maintaining balance in the case of a postural change from erect quadrupedal to erect bipedal. This article presents a hypothesis that the transition from quadrupedal to habitual upright bipedal locomotion was caused by qualitative changes in the nervous system that allowed controlling the more demanding type of locomotion. The ability to control a more demanding posture increases possibilities of interactions between the organism and the complex environment and consequently increases the survival rate, breeding possibilities, and chances for occupying a new environmental niche. Existing data show that ability to execute the more demanding type of locomotion was made possible because of changes in the frontal lobe and pyramidal system. Only after the more demanding posture was enabled by changes in the nervous system, could advantages of bipedal over quadrupedal locomotion be utilized, including better scanning of the environment, carrying food and infants, simultaneous upper extremity movements and observation of the environment, limitless manipulation of objects with upper extremities above the individual, and less space for rotating around the Z-axis. The aforementioned advantages of habitual bipedal over quadrupedal locomotion are present in physically complex environments, such as the forest, which is associated with the appearance of habitual bipedal locomotion. — Preceding unsigned comment added by Sekulic1965 (talk • contribs) 08:07, 11 April 2014 (UTC) Sekulic1965 (talk) 08:26, 11 April 2014 (UTC)


 * Regardless of the merits or flaws of this idea, until there is evidence (not just a hypothesis), it cannot be included. HCA (talk) 18:28, 11 April 2014 (UTC) If there is evidence, than this is not anymore hypothesis. So far we only have hypotheses without real crucial evidence. Hypothesis about increased capabilities of postural locomotor control and consequently appearance of upright body posture and locomotion is not credited on equal basis to rest of hypotheses. It should be among the rest of hypotheses on the main page about bipedalism. Sekulic 1965

Savannah Based Theory
I think that in the Savannah Based Theory section it would be worth mentioning something about how bipedalism in the savannah would have helped regulated body temperature by reducing the surface area of the body exposed to the hot savannah sun. The section of the Savannah theory that talks about the fossils having curved fingers suggesting bipedalism adapted to arboreal life could be its own section. In that section it could be mentioned that the arboreal bipedalism could have evolved from upright running in the trees aided by using the arms to grasp braches for balance. — Preceding unsigned comment added by Pallotta.8 (talk • contribs) 23:05, 29 September 2014 (UTC)

This article is great in many ways but can be improved in some parts. For one, it could mention how one of the purposes of the human foot is for propulsion. It talks about how it was built to support weight and maintain balance, but it does not mention the importance of shock absorption. If it weren't for shock absorption our joints could be worn down and not last as long. Also, the article could mention how the human foot evolved under selection to be a flexible rather than stiff structure. Christine K. — Preceding unsigned comment added by Koporc.3 (talk • contribs) 06:24, 1 October 2014 (UTC)


 * I'm not sure it should be phrased that way - as you point out, the human foot as a lot of roles, but the same could be said for the foot of a turkey or lizard, and you could easily say those those roles are required for any effective locomotory limb in any species. The referenced article, in contrast, is more about elastic energy storage and recovery as a specific adaptation in human feet. HCA (talk) 14:12, 1 October 2014 (UTC)

Response: I can see your point! This article does focus more around that subject, but I was just putting a suggestion for that part of the article. The evolution of the human foot has so many aspects to it, without them we wouldn't be able to walk the way we do today! I was just suggesting putting more content about it so the article was more informative, maybe having it as some extra/background information. Koporc.3 (talk) 18:00, 10 October 2014 (UTC)Christine K.

Suggestions
I had a couple of suggestions for this article. First, while this is over the evolution of bipedalism in general, I think this article could talk more in depth about the specific lineages and evolutions leading up to bipedalism in humans as well as after. Also, the evolution of sexual dimorphism/lumbar spine that accompanied bipedalism could be made into its own paragraph in this article. It is only briefly mentioned. Lastly, the theories as to why amphibians and reptiles never developed bipedalism could be added to the respective sections within this page. -Sam Stephensen


 * Agreed, though the last point is only correct of amphibians - the page already lists many examples of bipedal reptiles, including lizards, parareptiles, and *tons* of archosaurs (including dinosaurs, birds, and non-dinosaurian archosaurs). HCA (talk) 14:20, 1 October 2014 (UTC)

Some suggestions that I have for the page include the following: The Evolution of Bipedalism tab describes how there are twelve different hypotheses but fails to discuss each one. It’s missing the knuckle walking hypothesis. I think it could also use some more information on the traveling efficiency hypothesis, such as who proposed this. The Physiology tab could use more information about how different bones of the body changed or they could connect readers with the Human Skeletal Change due to Bipedalism page (https://en.wikipedia.org/wiki/Human_skeletal_changes_due_to_bipedalism) The Physiology tab could also discuss how the tibia is formed and that the way the bone is distributed helps to support the weight of humans walking bipedally.

Cole.622 (talk) 01:06, 2 October 2014 (UTC)

Suggestions: 1.) In the biomechanic's section, material can be added to discuss the efficiency of bipedalism compared to quadrapedalism and the kinematics in animals such as chimps that invoke bipedalism. 2.) I agree that the different hypothesis could be discussed more or even outlined and that there is little on here for a terrestrial shift for bipedalism. The inclusion of the Knuckle walking hypothesis would definitely help balance this. 3.) The flexible branch theory could also be added to the end of the Savanna-Based Theory which suggests that bipedalism arose arboreally and was retained as primates descended from trees rather than being innovative at the time.

Ondrejech.1 22:25, 22 October 2014 (UTC)


 * Be extremely careful about #1. "Efficiency" has a very specific definition, namely the fraction of input energy converted to useful output energy, and within biomechanics that usually means the ratio of external work to muscle chemical energy consumed.  Two organisms can have different Net Cost of Transport (as measured by either respirometry or isotope methods), but the same muscular efficiency. HCA (talk) 14:15, 23 October 2014 (UTC)


 * Good to know,thank you for the advice! — Preceding unsigned comment added by Ondrejech.1 (talk • contribs) 00:47, 28 October 2014 (UTC)

Suggestions-CK
This article could also include the evolutionary concepts that this subject relates to.


 * 1) To begin with, the development of the human foot has happened over millions of years which coincides with Darwin’s theory of gradualism. Our foot is the result of many years of change that occurred at a very slow rate.


 * 1) The development of the foot also had to be evolutionary advantageous or else it would not have been naturally selected for. Hominids who started walking most likely were able to give themselves and their offspring more resources to better survive because they developed new behaviors from traveling terrestrially such as hunting.


 * 1) The need to run was most likely naturally selected for as well; the stronger more propulsive foot was proven beneficial. Whether it was being able to run away from predators or chase after prey, the ability to run must have been very important because we can see it in the way the foot is designed. It most likely gave the organisms a better chance of survival, in which they were then able to reproduce and pass off their beneficial traits to their offspring.


 * 1) Another concept that this evolutionary adaptation goes along with is that of common descent. Even though it is a controversial topic, scientific research has proven that we have a shared ancestry with apes. The Hominidae include orangutans, gorillas, chimpanzees, bonobos and humans; our most recent ancestor are chimpanzees. This group which includes humans are referred to as the great apes. The divergence between humans and the last common ancestor is now estimated to be eight to ten million years ago.

As Francois Jacob wrote, “evolution is a tinker not an engineer”. Evolution did not suddenly produce organisms, organisms emerged from the genetic variation that was present in the already existing gene pool (National Academy of Sciences).


 * Evolution tinkered with the genetic information it already had available and over time new organisms and adaptations emerge from preexisting ones. You can see this with the present day human foot.

Koporc.3 (talk) 20:37, 18 November 2014 (UTC)Christine K.
 * You have five toes which are all in line with each other. Evolution took what used to be a diverged big toe used for grasping or manipulation and eventually after “tinkering” that toe was better placed when in line with the other toes in order for the organism to walk better. Also, the toes are shorter. The decreased need for grasping objects with the feet over time selected for toes that were not used for that. Keeping in mind though we still possess some flexibility, which is important for the mechanism of walking; you can flex your toes up and down. The hands however are used for the same original purpose, so tinkering with them was not as necessary as they were and are still used today for grasping and manipulation of objects. Also, one can deduce why the need for the foot to evolve to the way it is today by watching someone walk on their hands. It proves to us that the design is not as efficient. You can still walk on your hands and move forward and backward, but supporting your body weight for an extended period of time and balance proves to be more difficult.

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Knee bending
Bij most bipedal animals, including humans the knee bends forward. However by birds the knee bends backward. I see no mention of this.Smiley.toerist (talk) 11:01, 30 April 2019 (UTC)
 * Sorry. birds have 'normal' knees but they are invisible and wat we see bend the wrong way are the ancles. Smiley.toerist (talk) 11:13, 30 April 2019 (UTC)

Bipedalism
Bipedalism 70.70.230.22 (talk) 14:30, 16 December 2022 (UTC)

“where a tetrapod moves”
Definition incorrect: the Ostrich is not a tetrapod, though considered a biped. Gil_mo (talk) 07:24, 19 October 2023 (UTC)

Raccoon ability of walking on forelimbs
About the Limited bipedalism in mammals section. Raccoons also rarely walk on their forelimbs: https://twitter.com/CameraTrapSue/status/1772329198645809482?s=19 https://twitter.com/CameraTrapSue/status/1772278606640644351?s=19 I'm not sure how to incorporate this into the article, but I'd appreciate it if anyone that feels qualified would take a shot. Aveaoz (talk) 22:06, 18 April 2024 (UTC)