Talk:Animal locomotion/Archive 1

Diagram

Hi, can anyone give more information about what kind of diagram is desired? If anyone could post a link to a photo/scan of the diagram in Biology that would be very useful for illustrators. (see meta:Philip Greenspun illustration project/Round 1/Request list/17) thanks --pfctdayelise (talk) 01:16, 15 August 2008 (UTC)

Graph now exists: commons:Image:Energy cost locomotion en.svg. --pfctdayelise (talk) 01:18, 18 August 2008 (UTC)

Energetics

Please do not link to "aerobic" as it's a disambiguation page. Choose the correct usage from the page and link to that, or link to the Wiktionary definiton of the word. Thanks! You can help! Twirligig (talk) 21:14, 23 December 2008 (UTC)

Proposed project of interest - organismal biomechanics

Hi all, I'm trying to start a Wikiproject to cover Organismal Biomechanics, and I was wondering if anyone else would be interested? Articles such as animal locomotion. gait, muscle, and similar would be our targets. See my userpage for a list of what I'm planning to work on, including some truly awful articles in desperate need of attention. See proposal page at Wikipedia:WikiProject_Council/Proposals#Wikiproject_Organismal_Biomechanics. I'll keep anyone who signs up updated via their userpages until I get a project page made. Help of all kinds is appreciated, from brain dumps to wikifying, grammar and dealing with references. Mokele (talk) 01:38, 12 March 2009 (UTC)

New lead

As has been pointed out by Lambtron, there are some serious deficiencies in the intro. I took a whack at it before, and again just now, but it's still pretty unsatisfactory. Some aspects are just outright wrong (technically, movement isn't *essential* to survival since sessile organisms do just fine, but it is important), others are poorly phrased or insufficently explained. Any ideas? I figure it's overall structure should mirror the article and touch on key points such as energetics, terrestrial vs flight vs aquatic, generating forces, etc. Mokele (talk) 14:44, 21 July 2009 (UTC)

I reworked the intro paragraph; please have a look and revise as necessary when you have the time. Much more work to do here! Lambtron (talk) 20:35, 21 July 2009 (UTC)

Much better, thanks! Mokele (talk) 20:57, 21 July 2009 (UTC)

Human locomotion

why no human locomotion article ? --Penbat (talk) 20:38, 27 November 2010 (UTC)

Because humans are animals. Their locomotion in fundamentally the same as any other biped. Mokele (talk) 03:36, 28 November 2010 (UTC)

insufficient lead?

Is there a logical reason why the lead sentence seems to exclude gliding?__DrChrissy (talk) 12:05, 13 December 2014 (UTC)

Is gliding a type of self-propulsion? It seems more a method of travel than propulsion. Lambtron (talk) 16:14, 13 December 2014 (UTC)

Perhaps I should have worded my question a little more carefully. Should our use of "locomotion" exclude movement that is not self-propelled? Having looked at many definitions, they all include something like "moving from one place to another". I did not find one that used the term "self-propelled" or similar.__DrChrissy (talk) 17:19, 13 December 2014 (UTC)

I think the idea that the motion should be self-propelled (at least to some degree) has merit. The animal needs to have some control over where it is going. You wouldn't include animals being transported in boxes on ships in the article. I don't see that gliding animals are a problem. After all, they are still controlling the direction of the glide. Another example would be sliding downhill. If the animal has some control over how this happens then it would be a form of animal locomotion. If it has no control then it is an accident in progress. --Epipelagic (talk) 17:44, 13 December 2014 (UTC)

Yup, I agree entirely. I think it is my interpretation of the difference between "controlled-movement" and "self-propelled". A sugar glider will drop from a tree and guide itself to the tree of its choice, but gravity provides the propulsion. Just moving from one area to another, e.g. non-motile zooplankton, is clearly not locomotion.__DrChrissy (talk) 18:46, 13 December 2014 (UTC)

Gliders and sliders use gravity as their energy source for locomotion, but they still have some control over the outcome. Perhaps the article could refer to self-controlled propulsion, but difficulties then crop up with the term control. I once wrote an article called self-propelled particles about a minimum set of rules that each "particle" or animal in a swarm must obey for behaviours to emerge that are found in actual swarms. The individual particles are concerned only with what is happening to their nearby neighbours, and have no idea where they are going. But real world swarms exhibit directed behaviour not covered by the model, moving for example towards food sources and away from predators. That behaviour is presumably controlled by "particles" on the outer boundary of the swarm, which are the eyes of the swarm. This means that most particles in the swarm have no control over where they are going, yet we would still want to say they are "locomoting". --Epipelagic (talk) 19:29, 13 December 2014 (UTC)

Motion isn't classified as locomotion simply because the motion is controlled. Is a controlled downhill slide on a snowboard "human locomotion"? How about body surfing? The "loco" prefix implies some sort of integral propelling force. A train needs a locomotive -- which is an integral part of the train -- to propel it. Lambtron (talk) 19:58, 13 December 2014 (UTC)

Actually, the word in English derives from Latin loco "from a place" (ablative of locus "place") + motionem (nominative motio) "motion, a moving." The inference that "locomotion" is self-propelled is your inference. I have no problem with sugar gliders locomoting (made up word?). I also have no problem with animals behaving as a swarm; each individual is locomoting to ultimately get from A to B, but those at the periphery might locomote differently because of other concerns (I believe swarming birds respond to the behaviour of the nearest 7 individuals). I have more of a problem with e.g. spiderlings who spin a thread, then throw themselves to the mercy of the winds with no further control (as far as we know). This fits with with the derivation of the word, but not with my understanding of its useage.__DrChrissy (talk) 12:21, 14 December 2014 (UTC)

My impression of this article is that it's primarily concerned with mechanisms and methods animals employ to create motive forces. For example, how a frog propels itself into the air, or in the case you mentioned, how a spiderling throws itself into the wind. That said, I have no problem with discussing ways animals travel after they have created the requisite motive forces. I do think, though, that if the focus of the article is being changed to give equal weight to animal travel along ballistic trajectories and random air currents then the article should probably be moved to "animal movement" or something similar. Lambtron (talk) 20:27, 14 December 2014 (UTC)

"Animal movement" would include sessile animals. Locomotion means moving from one place to another. Sessile animals don't locomote, though they still move. For example, corals wave tentacles. DrChrissy pointed to the etymology for locomotion, a moving, from a place [1]. Note the technique or the means of how an animal moves is irrelevant when deciding whether it is undergoing locomotion. What counts is the process or the fact that it is moving relative to its environment.

Some dictionary entries are...

• movement or the ability to move from one place to another - Oxford dictionary [2]
• An act or the power of moving from place to place - Merriam-Webster [3]

The lead sentence in the article has gone through these changes...

• "In biomechanics, animal locomotion is the study of how animals move" - Richard001, 28 August 2007 [4]
• "The term animal locomotion describes the various methods by which animals move through their environment. "- HCA, 21 July 2009 [5]
• "Animal locomotion, which is the act of self-propulsion by an animal, has many manifestations, including running, jumping and flying." - Lambtron, 21 July 2009 [6]

Suppose you were in a hot air balloon, drifting in the wind. There may be little control but there is still a clear sense in which you are undergoing locomotion (moving from place to place). Following the etymology, beetles that use gravity to roll down sandhills to escape predators are undergoing locomotion, even if once they are under way they have have little control. Likewise, the spiderling uses the wind as a means to undergo locomotion. The mechanics or means of how the movement happens is irrelevant. All that counts is whether the animal is moving relative to its environment. The reference to self-propulsion in the lead sentence is misleading, since it could be read as implying that the animal must power itself or have control. --Epipelagic (talk) 22:47, 14 December 2014 (UTC)

Well that's the rub, isn't it? "Locomotion" has multiple meanings and can be used in various contexts to mean different things. What is clear is that the article currently is focused on how animals move themselves, not on how their environments change their physical shapes or transport them. It is also clear that the mechanics of movement is not only relevant, but a predominant theme throughout the article. For proof of this, please read in the article about energetics, cost of transport, the processes of burrowing through soil and swimming through water, overcoming inertia and maintaining momentum, and skeletal structures that facilitate various types of self-propulsion. I am not opposed to discussions of spiderlings floating in the wind, beetles rolling downhill or the parabolic trajectories frogs follow when airborne -- or gliding, but these topics are unsuitable for the lead sentence because they have only minor coverage in the article. Lambtron (talk) 02:20, 15 December 2014 (UTC)

Of course. I wonder if we are just arguing in separate directions, past each other? The examples you think don't belong in the lead were merely picked for discussion on this talk page, because they are can help clarify what locomotion is. I agree they don't necessarily belong in the lead. However I don't see that the concept of animal locomotion is ill-defined and has multiple meanings. The lead needs to clearly establish what animal locomotion is, which at the moment it doesn't. Then the rest of the article can go on to deal with modes of locomotion and the other issues you mention. --Epipelagic (talk) 03:39, 15 December 2014 (UTC)

Well, perhaps you're right; this thread started with a question about the absence of "gliding" in the lead and evolved into a debate about the meaning of "animal locomotion". What is animal locomotion if it isn't self-propulsion? That definition seems highly correlated with Webster's definition of having the "power to move from place to place" and Oxford's "ability to move from one place to another", and it fits the content of the article very well. I suppose that technically, an animal has the ability to move if not anchored in place, and it would have the power to do so if wind provided that power, but that's obviously a stretch and inconsistent with what this article is about. Lambtron (talk) 06:55, 15 December 2014 (UTC)

With that I disagree. The most recent book on animal locomotion, Principles of Animal Locomotion by McNeill Alexander, has an entire chapter titled "Gliding and soaring". --Epipelagic (talk) 07:29, 15 December 2014 (UTC)

Just to clarify, my original posting was perhaps badly worded. My objection is to the inclusion of the word "self-propulsion" because this excludes gliding, rolling, etc. These behaviours might have only minor coverage at the moment, but editors might have been reluctant to contribute to these because of the existing lead sentence.__DrChrissy (talk) 13:01, 15 December 2014 (UTC)

I have been researching the term "animal locomotion" and I still have not found a definition that includes the term "self propelled" or similar.

I propose the lead sentence reads " Animal locomotion, in ethology, is any of a variety of movements that results in progression from one place to another. Some modes of locomotion are (initially) self-propelled, e.g. running, swimming, jumping, flying, soaring and gliding. There are also many animal species that depend on their environment for transportation, a type of mobility called passive locomotion,[7] e.g. sailing (some jellyfish), kiting (spiders) and rolling (some beetles)."__DrChrissy (talk) 14:12, 15 December 2014 (UTC)

It's a fundamentally fuzzy issue, with a lot of "I'll know it when I see it". Thinking about it, what really matters is probably control, either throughout the movement or just at initiation - a ballooning spider has control over the initiation at least, a gliding lizard has some control over the trajectory, but a plant spore has none. Some "locomotion" may not even involve movement (a hovering hummingbird, a station-keeping fish), but still needs control. That may be key - locomoting animals have at least some active control over their position in space, and locomotion is the active exercise of that control, whether initiating a subsequently passive movement, actively moving from place to place, or maintaining position against a flow or gravity.

That said, we probably don't want to spend too much effort on a perfect definition (especially since it may be WP:OR), in favor of a practical one that's readable and informative. Note the page Reptile, the intro of which consisted of 20% useful, readable information and 80% excessively technical diversion into the paraphyly of the group, even though there was a huge section of the actual article about it. I would just grab something out of Alexander, Biewener, Hildebrand, or one of the other textbooks or popular-ish books, and cite it. HCA (talk) 15:06, 15 December 2014 (UTC)

HCA, can you give more fuzzy examples to support your view that the issue is "fundamentally fuzzy". The only fuzzy case I have seen so far is to do with hovering animals. Although a hovering hummingbird is stationary relative to the flower or the ground, it would not generally be stationary relative to the wind. Even if it was, it would still be actively engaging the mechanisms it uses for locomotion. Stationary phases could be regarded as an integral part of the hummingbird's journey, much as stops to let traffic through could be seen as an integral part of a car journey. Fish also hover in water, but because fish bladders can make them neutrally buoyant they have less need to engage their swimming muscles. It makes a certain sense to regard hovering hummingbirds as locomoting, though perhaps not hovering fish. --Epipelagic (talk) 20:35, 15 December 2014 (UTC)

I would consider ballooning spiders to be an excellent example - it's clearly a purposeful transportation movement by the spider, but they also rely solely on external forces. Ditto for salamanders rolling downhill. Even the soaring flight of vultures would be "fuzzy" since, although they need some active effort to get to the thermals, once they get there, they simply maintain a fixed posture with some control movements and let the environment provide the energy. If an animal can get a free ride, it will. HCA (talk) 15:33, 16 December 2014 (UTC)

I agree the hovering hummingbird is a fuzzy example, but not these additional examples. Ballooning spiders, salamanders rolling downhill and soaring vultures are not self-powered but use the wind or gravity as their power source. But following the etymology they are clearly locomoting. Generally, if you are moving from place to place you are locomoting. It doesn't matter what mode if used to locomote or where the energy comes from. Would you argue that drivers cannot not use cars for locomotion? Maybe if a salamander accidentally rolled down the hill it might be fuzzy, but even then I think it would be reasonable to say it underwent an involuntary or accidental locomotion. --Epipelagic (talk) 20:55, 16 December 2014 (UTC)

Wait, I think some wires got crossed. I'm not arguing for self-powering being required, but rather against it - hence examples of passively powered but controlled locomotion. I think a control-based definition would separate plant spores and drifting planktonic invertebrate eggs from ballooning spiders and soaring vultures, but that's completely 100% WP:OR on my part (though it's possible some of the more controls-oriented animal biomechanics folks have already arrived at the same idea). HCA (talk) 15:10, 17 December 2014 (UTC)

I think we can rule out spores as being a problem because this article is about Animal Locomotion. I have taken several of the other contentious examples to Passive locomotion in animals. I also extend this to parasites that locomote in the body and on the body. These are changing their locality, even though their host may be perfectly stationary. These can all be teased out in a logical way where locomotion means a change of place, and then explanation given about the mode of propulsion or relativity of place change. It was my hope that an editor would come along and merge this into the Animal locomotion article.__DrChrissy (talk) 17:48, 17 December 2014 (UTC)

The peculiarities of stationary fish and hummingbirds do not worry me. They are not stationary (am I saying they are not office supplies!). They are locomoting small distances, very quickly to remain in the previous position. A fish in a flowing stream may have an objective of remaining at point A. However, the stream will push the fish to point B, at which time the fish locomotes to get back quickly to point A. This might be a tiny distance, but it is using locomotion to get from point B to point A.__DrChrissy (talk) 21:16, 16 December 2014 (UTC)

The definition I proposed above is modified from "Locomotion, in ethology, any of a variety of movements among animals that results in progression from one place to another." found here [8]. I removed "among animals" because ethology is the study of animal behaviour and is therefore probably unnecessary.__DrChrissy (talk) 15:41, 15 December 2014 (UTC)

HCA hit the nail on the head -- it is a fuzzy issue. There is no formal, universally accepted definition of "animal locomotion". When I think of "animal locomotion" I don't think of barnacles being transported on whale bodies or spiderlings floating in the wind; I would classify those as "animal transportation", in which animals are being moved by external forces. That's an important distinction that is implicit if one examines the content of this article, and explicit given the article's current definition. If we employ the broadest possible interpretation of "locomotion" then we could logically include pet carriers and the Earth itself, which is "locomoting" animals through space. If this is truly unclear, instead of lumping "animal transportation methods" into this article -- which would completely change its character and focus -- why not just rename it to something unambiguous? Something like "animal locomotion (self-propelled)". Lambtron (talk) 16:27, 15 December 2014 (UTC)

It seems to me that it is only fuzzy when it is the method (mechanics) of movement that is considered. I'm afraid HCA left me a little confused that the term should relate to the element of control...but the question was left, how much control is needed for the movement to be defined as locomotion. If we define locomotion as "movement" of the animal with no mention of the mechanism, we can then include sections on self-propelled, minimally controlled, passive locomotion, transported animals, whatever. If we were to create a page Animal locomotion (self-propelled) an immediate respnse would likely be for someone to create Animal locomotion (passive) which I am sure would be immediately followed by editors wanting the articles to be merged with one title Animal locomotion. Can anyone verify that locomotion means self-propelled? If they can, this needs to be in the article to prevent this confusion arising again.__DrChrissy (talk) 19:33, 15 December 2014 (UTC)

Can you explain Lambtron why your idea, that animal locomotion must be self-propelled and excludes things like gliding or rolling downhill, is different from original research? Your examples of a barnacle on a whale and of animals transported by a carrier ignores that all motion is relative to something, which is why I used terms like "relative to its environment" several times above. The barnacle's environment is the whale itself and the environment of an animal being transported by a carrier is the carrier itself. --Epipelagic (talk) 20:43, 15 December 2014 (UTC)

In case it's not obvious, no one can "verify" that "animal locomotion" must involve either self-propulsion or "movement relative to environment" because the term lacks a standard definition. However, any reader can verify that the article is almost exclusively focused on self-propulsion, and that focus is consistent with both the definition in the lead and dictionary definitions of "locomotion". The lead is not a mandate; its job is to summarize the article which, in this case, is all about animal self-propulsion. Clarifying the topic in the lead is not OR -- it's standard WP practice and essential information for readers so they can quickly learn what the article is about. Lambtron (talk) 23:11, 15 December 2014 (UTC)

If the body of the article is as you say, "all about animal self-propulsion", then the article itself is unbalanced. Are you arguing that it is okay for the lead to be unbalanced because the body of the article is unbalanced? The usual convention is that the lead need not cite sources so long as they are cited adequately in the body of the article. But that is not an excuse to avoid verifying what is in the lead. --Epipelagic (talk) 00:00, 16 December 2014 (UTC)

I don't understand what you mean by unbalanced. Lambtron (talk) 03:56, 16 December 2014 (UTC)

I think the issue is being avoided here. Statements on WP should be verifiable. I have read dozens of definitions and none have included "self-propelled". I have asked for verification here on the Talk page but none has been forthcoming. Who else has used the qualification of "self-propulsion" in a definition of locomotion? I am going to place a verification tag in the article. I hate doing this to a lead sentence as it makes the whole article appear sub-standard, however...__DrChrissy (talk) 10:50, 16 December 2014 (UTC)

I agree that the issue is being avoided -- and necessarily so. How can we ever agree on what is meant by "animal locomotion" if it has no commonly accepted or formal definition? How can we "verify the accuracy" of an interpretation of such a term? So instead of trying to do the impossible, the lead takes a logical and pragmatic approach -- it explains what is covered in the article. I understand and appreciate your dilemma: You want to create and give equal weight to new content that is outside this article's current scope, but it's impossible to fabricate a new definition that will withstand the scrutiny the current definition is receiving. One way around this problem is to create a new article that encompasses and gives equal weight to all forms of natural animal movement, active and passive. That would allow this article to retain its concentrated focus on self-powered movement -- a diverse topic that IMO deserves its own article. If "animal locomotion" is deemed by consensus to be a confusing title for this article then let's find a better title for it. As for hypothetical future proposals to merge the new article with this one, let's cross that bridge when we get to it. Lambtron (talk) 15:02, 16 December 2014 (UTC)

"loco" = place, "motion" = movement. Where is the qualification this must be self-propelled? I respectfully request verifiable sources must be provided as there is dispute about the opening sentence (not the title). I am not asking for a consensus of outside parties or a commonly accepted definition, I am asking for just one single definition outside of this WP article that defines "animal locomotion" in terms of being "self propelled". Please....it only takes one verifiable source.__DrChrissy (talk) 15:31, 16 December 2014 (UTC)

On the other hand, WP has a page for species, yet there's an old saying in biology that the most vicious bloodsport in existence is locking a dozen biologists in a room and asking them to define "species". HCA (talk) 15:33, 16 December 2014 (UTC)

This is not about reaching consensus amongst a dozen biologists. It is about any one of those biologists being able to say that someone else has used "self-propelling" as being a necessary part of "Animal locomotion". Where is this single piece of evidence? Otherwise, this is Original Research and should be removed.__DrChrissy (talk) 15:46, 16 December 2014 (UTC)

Well, we could lock a dozen biologists in a room and task them with defining "animal locomotion", or we could avoid the ensuing bloodbath and accept the lead as is because it simply and clearly explains what the article is about. I'm a proponent of the latter, but I would encourage you to revise the lead if you feel you can improve its explanation of the content, or the title if you feel it doesn't match the content. Lambtron (talk) 16:48, 16 December 2014 (UTC)

Proposal

Here is a restatement of DrChrissy's proposal for the lead so it doesn't get buried:

" Animal locomotion, in ethology, is any of a variety of movements that results in progression from one place to another. Some modes of locomotion are (initially) self-propelled, e.g. running, swimming, jumping, flying, soaring and gliding. There are also many animal species that depend on their environment for transportation, a type of mobility called passive locomotion,[9] e.g. sailing (some jellyfish), kiting (spiders) and rolling (some beetles)." (from DrChrissy above)

• There seem to be some delicate issues to do with how and whether control by the animal enters into the picture. As well as "passive locomotion", could something be added about "active locomotion", moving "purposefully from place to place". [10] Also, I'm not sure that jumping, soaring and gliding should be described as self-propelled. Maybe as self-initiated. --Epipelagic (talk) 21:05, 15 December 2014 (UTC)

I support the idea of incorporating "purposeful locomotion" and/or "non-purposeful locomotion". The Portugese man o' war drifts (without purpose) completely at the mercy of winds and tides (although it can deflate its sail and temporarily sink ....purposeful locomotion?). The flea jumps 100 x its height but has no control over its direction (purposeful escape, but non-purposeful control of direction). We can sort out all these differences once we agree on the lead sentence/s which at the moment is exclusive rather than inclusive.__DrChrissy (talk) 22:34, 15 December 2014 (UTC)

• What about hummingbirds hovering? Lambtron (talk) 23:11, 15 December 2014 (UTC)

That's currently being discussed above. --Epipelagic (talk) 00:00, 16 December 2014 (UTC)

Why was the lead changed while this discussion is in progress? Shouldn't there be at least some sort of consensus before major unilateral revisions are made? Lambtron (talk) 16:53, 16 December 2014 (UTC)

I changed it for one simple reason - the previous version was not verified...despite repeated requests. The current defintion/opening sentence can, and is, verified.__DrChrissy (talk) 18:30, 16 December 2014 (UTC)

There is clear consensus for these changes. You seem to be persisting with the original research you introduced into the lead, requiring all animal locomotion to be self-propelled. You have been repeatedly asked to verify your claim with reliable sources. In case you didn't notice, DrChrissy, perhaps motivated by your obduracy, has just written an excellent new article, Passive locomotion in animals. The article is about animal locomotion which is not self-propelled. I have linked some policies and guidelines relevant to this discussion which may further clarify things for you. --Epipelagic (talk) 18:56, 16 December 2014 (UTC)

It seems to me that this article, which is quite important to zoology, is still unbalanced. The scope is still excessively constrained, and should include more acknowledgement of things like animal migration and animal navigation. Also, there should be a section on the reasons why animals need to locomote, such as the capture of prey and the avoidance of predators. The ability to locomote competently is a key survival strategy, and that should be brought out in the article. Some of these issues are mention briefly in the second paragraph of the lead, but not really followed up in the body of the article. --Epipelagic (talk) 10:07, 18 December 2014 (UTC)

I usually see gliding listed under terrestrial locomotion, as opposed to powered flight, e.g., flying squirrels vs. birds. I suppose the difference is that the power for the glide is usually supplied by scansorial locomotion, i.e., climbing. Moving to a higher place increases your potential energy. Gliding converts potential energy into kinetic energy. Zyxwv99 (talk) 02:57, 24 March 2015 (UTC)

Scansorial v arborial

In the section "Terrestrial" it says, "Some animals are specialized for moving on non-horizontal surfaces. One common habitat for such climbing animals is in trees." Climbing animals links to Arboreal locomotion. Climbing locomotion is actually known as "scansorial" and is not quite the same as arborial.

Locomotor mode / Descriptive definition

• Gliding

Bridge gaps between trees by gliding usually with patagium

• Arboreal Spend most of the time in trees foraging, traveling, resting, but occasionally travel on the ground

Scansorial

• Capable of climbing for escape, eating, or leisure, and probably spend a considerable time both in

the trees and on the ground

• Terrestrial

Spend most of time on the ground, but able to swim, climb, and burrow occasionally, but not specialized for those

• Semiaquatic

Capable of swimming for dispersal, escape, or foraging as well as on the ground

• Semifossorial

Regularly dig for food or to build burrows for shelter, but do not exclusively live underground

• Fossorial

Efficiently dig burrows for shelter or foraging underground exclusively

• Saltatorial

Capable of jumping

Also, humans and most terrestrial placental mammals have a "parasagittal gait." Birds do to, but evolved it independently. The sagittal plane is the anatomical plane (imaginary construct) that divides the body into a left half and a right half. A parasagittal plane runs parallel to the sagittal plane. When we humans walk our limbs move forward and backward, each within a plane defined by the joint that attaches the limb to the torso. When standing in the resting position, the limbs hang straight down. Same for dogs, cats, horses, and cows.

Rock hyraxes, on the other hand, are said to have an armadillo-like gait. Monotremes are widely reported as having a "reptile-like" gait, although scholars now seem about equally divided on whether this is correct. Some think the monotreme gait is largely an adaptation to semi-fossorial locomotion, which adapts readily to semi-aquatic due to the similarities of the forelimbs and shoulder girdle, i.e, digging animals loosen the earth, then "swim" through the soft earth.

Zyxwv99 (talk) 21:11, 22 March 2015 (UTC)

Interesting stuff, but I don't understand why a rock hyrax and an echidna (monotreme) are not also parasaggital. Why are they classified differently?__DrChrissy (talk) 22:16, 22 March 2015 (UTC)

The problem is, many of those terms are very sloppily used, even in the scientific literature, with widely varying prevalence. I called the page "arboreal locomotion" as a catchall for climbing locomotion because the same principles apply whether it's a tree or a mountain face, but also because the term is much, much more familiar to the general reader (and about 95% of the work out there is specifically on arboreal situations). It's easy to make categories and talk about specializations, but how do you draw lines, especially with incomplete data? Is 60% of the time in water enough to be semi-aquatic? 40%? 30%? 80%? What if nobody has quantified their movements in the wild, or demonstrated performance tradeoffs for various traits (it's harder than you think)? Similarly for "sprawling": how adducted do the humerus and femur need to be before they before "erect" or "semi-erect"? Is is still parasagittal if the're a mere 5 degrees of abduction? 10 degrees? I guess I'm saying don't attribute more specificity and precision to these terms than is really present; ultimately, they're all just human-imposed categorizations. Add clarifications and such as needed, but don't get too carried away. HCA (talk) 22:34, 22 March 2015 (UTC)

Yup, I understand what you are saying. I recently added videos of blennies climbing up a perspex sheet. I really don't know how this should be classified, or whether it is actually just a behaviour that occurs in the laboratory. It seems likely they could use this to climb trees, so are these arboreal fish?__DrChrissy (talk) 22:42, 22 March 2015 (UTC)

I've spent a lot of time on YouTube watching videos of armadillos and rock hyraxes, and still can't figure out what that's about. It does, however, come up in the literature. More to the point, I've been reading dozens of research papers from Google Scholar on early mammals, pre-mammals, and near-mammals, and the terms listed above come up a lot. As for how you determine these things, paleontologists are going by adaptations visible in the fossils. I think this is explained in the article cited. It's not that much different from looking at the teeth and trying to figure out it it's an insectivore, an herbivore, or whatever. In other words, there are distinctive patterns. So semi-aquatic would be defined in terms of its skeletal structure and how it moves. And finally, as Wikipedians I don't think it's our job to classify anything based on our own opinions. We're supposed to find out what the experts have to say. It's just that at some point we also have to make the effort to understand what they're saying and why. That's why I'm going to watch some more rock hyrax and armadillos videos Zyxwv99 (talk) 01:40, 23 March 2015 (UTC)

Oh, I'm not saying don't follow the sources. I'm just saying to be aware that these terms are not always used in very rigorous ways, either in extant or extinct species, even in the technical literature, and for every clear example, there's an ambiguous one. The issues with armadillos and rock hyraxes are just such examples. Regard them as tentative labels until verified by sufficient field observations or lab studies. They're not valueless, but don't take a single paper's statement as gospel truth, either. HCA (talk) 14:56, 23 March 2015 (UTC)

My impression is that they've been doing lab studies with detailed measurements since Leonardo da Vinci. In the early days of science (Galileo, Newton) this sort of thing was all the rage. That's when they established the convention of rounding off angles to the nearest five degrees, measuring abduction, adduction, rotation, pronation, etc. When photography was invented in the early 19th century they took this to new heights. Then in the 1870s Eadweard Muybridge pioneered the use of cinematography in animal motion studies. In 1895 the x-ray tube was invented. Pretty soon they had x-ray movies of the duck-billed platypus filmed from above, from the side, and from in front, with the movies analyzed frame-by-frame. Since then they've figured out how to measure the metabolic energy animals expend in various forms of locomotion. The platypus expends 2.7 times as much energy walking on land as it does swimming in water. The hard part is that I am just learning this stuff myself and am struggling to learn difficult words (such as scansorial, fossorial, parasagittal) that I keep running into while trying to learn about early mammals. Zyxwv99 (talk) 15:17, 23 March 2015 (UTC)

Oh, I know; comparative biomechanics is my field. But, like most things, the closer you get to it, the more you see the annoying complexities and the gaps in our knowledge. For instance, there's a LOT of animals for which we don't actually have quantification of their wild movement patterns, actually measuring truly maximum performance is fraught with difficulties, and mechanically intuitive tradeoffs can be concealed in statistical noise, differences in overall individual quality, or compensatory adaptations. There's a lot of stuff we simply don't know, species that nobody's ever gotten into the lab, areas that just plain don't receive much attention. Plus, for every good rule in biology, there's always an exception, possibly including that rule. Every good paper will raise more questions than it answers, after all. ;) HCA (talk) 19:58, 23 March 2015 (UTC)

Pedalism Section

I am not sure the title of this section "Pedalism" is the best choice, and the initial paragraph in this section could also probably be improved. As it is, the initial paragraph (sentence) attempts a definition of pedalism but fails in this regard, especially since the objective of the initial paragraph would be to introduce the subsections under Pedalism. Just quickly searching for a definition to the word "pedalism" (e.g., Google search) fails to even find a definition of the word in general. However, what IS clear is that the word derives from French/Latin (1605-15; (< French pédale) < Latin pedālis of the feet), meaning "foot/feet." Therefore, if "pedalism" is in fact an actual word, it would mean "having to do with the number or use of feet" and not with the number of legs or arms (i.e., not all appendages which appear to be legs may have feet or be used or meant for walking or for locomotion at all).

In addition, this section does not clearly delineate whether "pedalism" is determined by the number of "walking appendages" or by those which are actually USED for locomotion. For example, because a praying mantis primarily uses its front pair of major appendages as "arms/hands" does that ACTUALLY make a praying mantis a quadruped? According to Merriam-Webster a quadruped is "an animal that has four feet." This makes sense etymologically ("ped" means "foot/feet"), and also because the praying mantis doesn't really use the front pair of appendages as feet. Jdevola (talk) 14:35, 1 June 2016 (UTC)

I've removed the neologism as inappropriate. Mantises walk on 4 or 6 legs, which doesn't make them quadrupeds; the Nymphalidae do walk on 4, but they aren't Quadrupeds either. We should focus on the topic, which is locomotion, and avoid needless WP:OR-ish definition which leads nowhere useful. Most of the difficulty goes away when text is fully cited, by the way. Chiswick Chap (talk) 07:24, 4 October 2016 (UTC)

Should Fish locomotion be moved?

Just to let people know there is discussion over at Fish locomotion regarding whether it should be moved to Fish movement. DrChrissy ^(talk) 20:28, 1 October 2016 (UTC)

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Active flight?

Among aerial locomotion I find gliding, soaring and balooning as subsections, but not a single word about active flight (i.e. wing-flapping used by most birds, winged insects and also by bats). I looked twice and still didn't find it! --Episcophagus (talk) 11:43, 14 October 2016 (UTC)

There was a not terribly wonderful paragraph, uncited. I've added a section heading and main link, which only go to emphasize that a proper summary of the main article is needed. Actually, the main article (Flying and gliding animals) does rather need to be split into two (say, Active flight in animals, Gliding in animals). Chiswick Chap (talk) 11:52, 14 October 2016 (UTC)

Do you mean article or section? DrChrissy ^(talk) 13:27, 14 October 2016 (UTC)

Ah, thanks. I've added the main article link I intended. Chiswick Chap (talk) 13:52, 14 October 2016 (UTC)

I agree with such a split, but of course this is a discussion we should be having over there. DrChrissy ^(talk) 13:54, 14 October 2016 (UTC)

The immediate concern is to write, illustrate, and cite the section over here... Chiswick Chap (talk) 14:09, 14 October 2016 (UTC)

locomotory organ, ?

See Talk:locomotory organ, does locomotory organ deserve at wiktionary entry to clear up what it is / isn't (are legs organs .. or not) MfortyoneA (talk) 20:07, 5 April 2017 (UTC)

I see the term "locomotor structure" used more often, but both are pretty rare, even in the primary literature, and usually reserved for either making broad generalizations about all animal movement or to describe some particularly weird anatomical trait of a given species which is used in locomotion. HCA (talk) 14:34, 8 April 2017 (UTC)

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Side-issue

The sections "Quantifying body and limb movement" and "Methods of study" diverge from the article's subject, how animals move, to the subsidiary topic of how scientists may choose to study how animals move. As the article is already rather long, I suggest we split these off as a subsidiary article, leaving a 'Main' link and a brief summarizing paragraph. Maybe I'll just boldly go there before any more of it accretes... Chiswick Chap (talk) 12:37, 11 September 2020 (UTC)

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