Talk:Physiology of dinosaurs

Scientific Classification
It would be more scientific and proper to instead use the term, endothermic, to refer to "warm-blooded" animals. Just a suggestion..

Misc
Does anybody know of any research that deals with whether ornithischians had bird-like air sacs? Philcha 21:21, 9 November 2006 (UTC)


 * <>

Well duh, that's the definition of "dinosaurs". Birds aren't dinosaurs anymore than the Japanese are Caucasians. Voortle 19:51, 23 November 2006 (UTC)
 * No. In practically all modern scientific literature birds are considered dinosaurs. The definition in no way excludes birds. That's the conservative scientific consensus. John.Conway 12:44, 11 April 2007 (UTC)

New discovery about how birds breathe casts doubt that birds descended from any known theropod dinosaur. Rainy Day (talk) 19:54, 1 February 2010 (UTC)


 * No, it doesn't. By that logic, tetrapods could not have evolved from fish, because tetrapods need their ribs to breathe (primitively, at least) while fish don't.  It's asinine. Mokele (talk) 20:55, 1 February 2010 (UTC)

"some may be warm blooded and some cold"
I think this should be removed because it's pure speculation. In particular it fails to address the fact that all known early (Triassic) dinosaurs had erect limbs, which implies that they were about as active as mammals and birds of the same size and therefore needed fairly fast metabolisms.Philcha 23:37, 22 December 2006 (UTC)

I second that--50.195.51.9 (talk) 13:55, 10 December 2012 (UTC)

Bad Bibliography?
The citation for Bakker's article in nature is wrong. Anatomical and Ecological Evidence of Endothermy in Dinosaurs, by Robert T Bakker, was published in Nature  238, pp 81-85. His nature 229 article contested the view that apatosaurus/brontosaurus lived underwater.
 * Okay, it's fixed. J. Spencer 20:55, 8 March 2007 (UTC)

Predator/Prey ratios

 * "There are no communities of large, cold-blooded animals to-day, so we have no grounds for assuming that such communities would have higher predator-prey ratios."

The section mis-characterises the debate here. Bakker uses other fossil communities as control trails to calibrate predator/prey ratios. There are criticisms of the p/p argument, but this list isn't a good explanation. John.Conway 12:50, 11 April 2007 (UTC)

And there are big problems with comparing living animals to long-extinct ones, particularly when we use words like 'large.' There are no land animals even remotely similar in size to say, sauropods, hadrosaurs or tyrannosaurids. 'Every comparison limps.'--Gazzster 09:25, 29 April 2007 (UTC)


 * I'm not sure Bakker did just compare "large" animals, and he certainly didn't just compare dinosaurs with living ecosystems. Ah well, I think I'll do a rewrite of the p/p section myself. People seem strangely uninterested in this article now. —John.Conway 10:15, 10 May 2007 (UTC)

Don't be discouraged John, it's a great article. Kudos.--Gazzster 05:19, 12 May 2007 (UTC)

Propose to move this article to Physiology of dinosaurs
I know I've been a bit of a movaholic recently, but the title of this article is clearly POV. I think we should move it to Physiology of dinosaurs, but I'm open to other suggestions. —John.Conway 16:13, 9 May 2007 (UTC)
 * I like it, with the old name kept as a redirect. J. Spencer 21:01, 9 May 2007 (UTC)

Yeah, good one! Besides POV, it's not a user-friendly title. We might even consider merging it with dinosaur. I mean, if you opened up Encyclopedia Brittanica looking for info about thermo-regulation of dinosaurs you'd look up 'dinosaurs', not 'warm-blooded'.Cheers.--Gazzster 22:12, 9 May 2007 (UTC)


 * I think the topic is large enough to warrant its own article — though it needs a substantial rewrite. Of course, it will still have the summary in the dinosaur article. —John.Conway 08:27, 10 May 2007 (UTC)

Proposed new structure
The article needs a good deal of simplification of it's structure and I'd like to start sketching on out here. To go with the new title, I think we should take some of the emphasis off metabolic rates per se, and break it down into systems (feel free to expand/edit this) —John.Conway 15:23, 11 May 2007 (UTC):


 * Metabolism
 * Growth Rates
 * Bone histology
 * Predator/prey ratios
 * Anatomical evidence/"Cruising speed"


 * Respiratory System
 * Air sacs
 * Nasal turbinates


 * Cardiovascular system
 * Phylogenetic bracket
 * Thescelosaurus heart
 * Sauropod controversy

Looks interesting. I don't know whether this would work, but it's a suggestion: divide the article into a 'for' and 'against' format. It's simple on the one hand, but maybe you'd have to treat of the same issues in both sections? Dunno. What's the 'sauropod con' by the way? Is it the problem of a reptilian heart pumping blood up to the brain?--Gazzster 05:25, 12 May 2007 (UTC)


 * I really don't like the way for/against article pan out - they end up just reading like he said/she said, and ends up repetitive. Plus, that's not the state of the science these days (I don't think it ever was as much as Bakker made out). Also the non-metabolic aspects of dinosaur physiology are important, and deserve treatment outside of mere supporting arguments about metabolic rates.


 * Yeah the sauropod controversy is the problem of pumping blood to the head -- though I think it can be expanded to lot of dinosaurs. —John.Conway 10:54, 12 May 2007 (UTC)

Cool. You're right.--Gazzster 12:45, 12 May 2007 (UTC)
 * The question is, what do we want the article to focus on? People looking for the physiology of dinosaurs are probably expecting a discussion of warmblooded vs coldblooded. I'd love for this to be a great article, but I'm having trouble wrapping my mind around structuring it. J. Spencer 02:43, 21 June 2007 (UTC)

Perhaps instead of calling it Physiology of Dinosaurs, we call it Thermodynamics of Dinosaurs or Metabolism in Dinosaurs or Temperature Regulation in Dinosaurs, with appropriate redirects. It could be organised this way:


 * I like having an article on the various interconnected physiological systems, as they all co-support each-other. Also, it's a good place to have discussion on things like respiratory and cardiovascular systems, which would be difficult to raise to article status on their own.
 * Again, I don't really like the pro/con structure, because we can't treat dinosaur like a "lump" (few people argue that small theropods were cold blooded but several argue that sauropods were, for example), and because it's not the state of the literature.
 * However I think you've pointed a few important things I missed out in my proposed structure above, so how about:


 * Metabolism
 * Intro w/ explanation of endothermy and ectothermy + advantages
 * Evidence
 * Growth Rates
 * Bone histology
 * Predator/prey ratios
 * Anatomical evidence/"Cruising speed"
 * Thermoregulatory structures in dinosaurs (plates, sails, etc)
 * The possibility/probability of varying metabolic models in dinosaurs.


 * Respiratory System
 * Air sacs
 * Nasal turbinates


 * Cardiovascular system
 * Phylogenetic bracket
 * Thescelosaurus heart
 * Sauropod controversy

—John.Conway 11:34, 21 June 2007 (UTC)

Cool, man. If I can help, please let me know.--Gazzster 11:56, 21 June 2007 (UTC)
 * Where would the recent discussion of opisthotony as evidence for elevated metabolic rates go (that animals with high metabolic rates are more susceptible to anoxia and thus having their necks and tails arch over their bodies upon death, as is seen in many dinosaur specimens)? J. Spencer 02:19, 22 June 2007 (UTC)
 * Interesting idea. Can you supply references? The only discussion I've seen are in expert forums like CMNH. the most obvious object to opisthotony as evidence elevated metabolic rates is that dinos and birds the only creatures whose anatomy allows opisthotony, since their necks are significantly longer and more flexible than those of other vertebrates.Philcha 22:45, 26 June 2007 (UTC)
 * It's Faux and Padian, 2007, from the May issue of Paleobiology; the abstract can be found here. J. Spencer 02:18, 27 June 2007 (UTC)
 * Thanks for the ref. When read it I realised I'd seen it before. I don't think it's good evidence for dino metabolism: the authors admit that toxins and other factors can cause opisthotony (in fact alkaloid poisoning and dessication of neck tendons were proposed as explanations for opisthotony pretty soon after opisthotonic fossils were first found, mainly of Compsognathus and Archaeopteryx); they don't offer any explanation of why the victims should have died of hypoxia, and that would be difficult considering how often dino fossils are found in this posture. For a more detailed critique see Dino Mailing List, including the rest of that discussion thread. It's worth looking out for further developments in this topic, but at present it's too speculative to be included here.Philcha 11:02, 11 July 2007 (UTC)

I really don't like the re-structure. The old structure was simple: In the new structure the part about crocs is very awkwardly placed.
 * Summary of the history of the debate about dino warm-bloodedness.
 * Summary of various types of evidence about metabolic rates - most favouring fairly high BMR, especially for coelurosaurids.
 * How could dinos have maintained high BMR and therefore probably homeothermy?
 * The problem of how fast warm-bloodedness evolved in dinos / archosaurs, considering that crocs are cold-blooded.

I appreciate that you're trying to broaden the scope of the article so that it does not focus exclusively on warm-bloodedness. But:
 * Is there enough material that relates to aspects of dino physiology other than warm-bloodedness? I'm not sure there is.
 * Even if there is, I think a better structure would be: (a) various individual aspects of dino physiology; (b) the issues about warm-bloodedness, including history of the debate, evidence not already discussed (polar dinos, limb posture), possible mechanisms for high BMR and homeothermy and finally the croc puzzle.Philcha 22:45, 26 June 2007 (UTC)

Stuff cut from article
I cut the following in the restructure, but we might want to re-include it at some point: —John.Conway 15:27, 25 June 2007 (UTC)

*Richard Owen coined the name "dinosaurs" in 1842 and speculated that they were active and warm-blooded. Most 19th century scientists and illustrators (e.g. Charles R. Knight) followed this view. *In the first half of the 20th century scientists emphasized dinosaurs' reptilian heritage and regarded them as sluggish and cold-blooded. *In 1968 Robert T. "Bob" Bakker, inspired by John Ostrom's analysis of Deinonychus, published a paper which proposed that dinosaurs were warm-blooded and active. This started a vigorous debate about the metabolism, activity level and temperature regulation of dinosaurs.

==How could dinosaurs have maintained stable, fairly high temperatures?== If dinosaurs were at least fairly warm-blooded (which is still subject to debate), one has to ask how they maintained stable, fairly high temperatures. Several mechanisms have been proposed, and at least some dinosaurs may have used combinations of mechanisms or different mechanisms at different stages in their lives.

===Inertial homeothermy=== Inertial homeothermy is found in many large creatures - because of their low ratios of surface area to volume, they lose and gain heat very slowly. But the earliest dinosaurs, many later dinosaurs and the young of all dinosaurs were too small to benefit from inertial homeothermy.

===Gut fermentation=== When large animals eat coarse vegetation, digestion takes so long that the food ferments and generates heat. But this mechanism is impossible for carnivores and for the small dinosaurs mentioned above.

===Metabolic heat generation=== Birds and mammals generate heat by converting fat into energy - this is known as endothermy.

If dinosaurs were at least fairly warm-blooded, endothermy is the only known thermoregulatory mechanism which would have been available to small species and to very young dinosaurs.


 * Looks good so far; the bulleted history section as a lead was pretty soft, but I think its general ideas could be rehabilitated if we wanted such information back in (perhaps borrowing from Dinosaur and Dinosaur renaissance)?. J. Spencer 15:32, 25 June 2007 (UTC)


 * I think removing these items was a mistake. I'm old enough to remember when everybody just assumed dinos were cold-blooded (and the more active mammals drove them to extinction by eating their eggs); and the history also explains why the debate still is often heated and even acrimonious (you should see some of the comments in the expert forums) - paradigm shifts usually meet fierce resistance. The other stuff about possible mechanisms for maintaining high BMR and homeothermy is important to in order to complete the analysis, particularly the point that gut fermentation and inertial homeothermy were not possible for small dinos and therefore not possible for the earliest dinos.Philcha 23:00, 26 June 2007 (UTC)


 * I'm all for having historical context, but this was just too thin. Having said that, though, there really should be a brief description of attitudes, which could have a robust paragraph for each of the cut historical bullet points, plus a "modern" paragraph saying where we've gone since Bakker and Ostrom. J. Spencer 03:33, 30 June 2007 (UTC)


 * I understand the historical context, but I agree with J. Spencer that the above was too thin -- it just didn't do the job. I also think that something needs to be written, perhaps based on the physiology section of the dinosaur renaissance article. As for debate recently, it's vastly altered to the point of non-existance, and rarely acrimonious. I haven't seen many fights over it on the DML in the last six years (and there's been no shortage of acrimonious debate on other subjects on the DML!). — John.Conway 19:06, 30 June 2007 (UTC)

History
I threw together a couple of general paragraphs on the early history. How's the tone?

Early interpretations of dinosaurs: 1820s to early 1900s
The study of dinosaurs began in the 1820s in England. Pioneers in the field, such as William Buckland, Gideon Mantell, and Richard Owen, interpreted the first, very fragmentary remains as belonging to large quadrupedal beasts. Their early work can be seen today in the Crystal Palace Dinosaurs, constructed in the 1850s and which present known dinosaurs as elephantine lizard-like reptiles. Despite these reptilian appearances, Owen speculated that dinosaur heart and respiratory systems were more mammal-like than reptile-like.

With the discovery of much more complete skeletons in the western United States, starting in the 1870s, scientists could make more informed interpretations of dinosaur biology. Edward Drinker Cope, opponent of Othniel Charles Marsh in the Bone Wars, propounded at least some dinosaurs as active and agile, as seen in the painting of two fighting "Laelaps" produced under his direction by Charles R. Knight. In parallel, the development of Darwinian evolution, and the discoveries of Archaeopteryx and Compsognathus, led Thomas Henry Huxley to proposed that dinosaurs were closely related to birds. Despite these considerations, the image of dinosaurs as large reptiles had taken root, and most aspects of their paleobiology were interpreted as being typically reptilian for the first half of the twentieth century.

Changing views and the Dinosaur Renaissance
However, in the late sixties views began to change. Paleontologist Robert Bakker, in a series of papers in the 70s and 80s, beginning with his 1968 paper The superiority of dinosaurs, argued strenuously that dinosaurs were warm-blooded and active animals; capable of sustained periods of high activity. In most of his writings Bakker framed his arguments as new evidence leading to a revival of ideas popular the the late 19th century, frequently referring to an ongoing dinosaur renaissance. He used a variety of anatomical and statistical arguments to defend his case, the methodology of which was fiercely debated among scientists.

These debates sparked interest in new methods for ascertaining the palaeobiology of extinct animals, such as bone histology, which have been successfully applied to determining the growth-rates of many dinosaurs.

Today, it is generally thought that many or perhaps all dinosaurs had higher metabolic rates than living reptiles, but also that the situation is more complex and varied than Bakker originally proposed. For example, while smaller dinosaurs may have been true endotherms, the larger forms could have been inertial homeotherms, or many dinosaurs could have had intermediate metabolic rates.

arbitrary break
I'm much happier with this. Shall we add it? J. Spencer 15:00, 1 July 2007 (UTC)


 * Looks good, stick it in. —John.Conway 16:00, 1 July 2007 (UTC)
 * 'Tis done. J. Spencer 17:09, 1 July 2007 (UTC)

Heading "Anatomical Evidence"
I originally titled this section "Posture and gait", and still think it's a much better title because the evidence and arguments all relate specifically to posture and gait rather than to other features of skeletal anatomy, while soft anatomy is covered in other sections of the article.Philcha 10:16, 11 July 2007 (UTC)
 * I think a postural heading makes more sense at this time than "Anatomical Evidence". If we were to add to that section, a more general heading would be needed, but the writing covers a more specific topic. J. Spencer 15:03, 11 July 2007 (UTC)

Heading "Evolutionary context"
I originally titled this section "The crocodilian puzzle", and still think it's a much better title because the crocs raise all the paradoxes discussed in the section: cold-blooded but with anatomical features otherwise found only in warm-blooded animals; early crocs looked distinctly cursorial; if early dinos were warm-blooded and all other archosaurs were cold-blooded, dinos or their unknown immediate ancestors became warm-blooded in an incredibly short time (compared with the therapsid-mammal lineage). These problems would not exist if there were no extant crocs or if modern crocs were at least partially warm-blooded.Philcha 10:28, 11 July 2007 (UTC)
 * This one I think should stay as "Evolutionary context", but I think the text should work in birds as well somewhere for phylogenetic bracketing purposes. J. Spencer 15:03, 11 July 2007 (UTC)
 * What does "phylogenetic bracketing" do for the reader? When I produced most of the content of this article in Jan 2007 (see the history), it had a fairly easy-to-understand progression: arguments and evidence (mostly favouring moderate to high BMR and homeothermy); but if dinos were at leasty fairly "warm-blooded" from the start, crocs create paradoxes: "warm-blooded" features in cold-blooded animals; and if the last common ancestor of crocs and dinos, which lived in the early to mid Triassic, was cold-blooded while dinos (mid to late Triassic) were warm-blooded, dinos must have evolved "warm-bloodedness" incredibly fast (compared with evolution of mammals). So I titled it "The crocodilian puzzle", which is accurate and, when it appears in the TOC, tells the reader up front that there is a puzzle.
 * I think part of the problem is the change from "Warm-bloodedness of dinosaurs" to "Physiology of dinosaurs". At present virtually all the published material appears to focus on thermoregulation. The only exceptions I can think of right now are: the problem of how sauropods got blood to their brains (the "giraffe" problem); the problem of how sauropods breathed (all that "dead space" in a trachea longer than any giraffe's); whether dinos (especially sauropods - again!) used gizzard stones to aid digestion; the discovery that female T rex had a type of bone in her legs which is currently found only in female birds and is thought to be a calcium store for egg-laying. Even if the page included all this, it would still be 80% about thermoregulation, and some of the additional topics have been discussed mainly in the context of thermoregulation (the sauropod breathing problem; gizzard stones).
 * We may actually need an overall "Physiology of dinosaurs" article plus more detailed articles on specific topics including "warm-bloodedness" (for which there is easily an article's worth of content). And for an article specifically about "warm-bloodedness", I still think the structure I produced in Jan 2007 was considerably better.Philcha 16:30, 13 July 2007 (UTC)

Reproductive biology
I've just added this section - the 2nd one that's not mainly about thermoregulation / metabolic rate.

I've also moved "Respiration" before "Metabolism". IMO "Metabolism" should come last because it uses arguments / evidence from the other sections. I'll check to polish up inter-section references. Philcha (talk) 10:33, 20 January 2008 (UTC)

Physiology of dinosaurs is collab for March 2008
Nominated December 9, 2007;

Support:


 * 1) J. Spencer (talk) 01:59, 10 December 2007 (UTC)
 * 2)  Firsfron of Ronchester  16:23, 10 December 2007 (UTC)
 * 3) --Gazzster (talk) 01:17, 29 March 2008 (UTC)

Comments:


 * It's a topic of perennial interest to the general public (every dinosaur article in newspapers always works in "cold blooded" and "warm blooded" somewhere), already has a lot of work put into it, and can be compartmentalized, i.e. people can take on certain sections that interest them. Inline citations are a big issue, as is deciding if the current format is best. J. Spencer (talk) 01:59, 10 December 2007 (UTC)

Hello? Anybody around? J. Spencer (talk) 03:50, 7 March 2008 (UTC)

Yes, but my ideas on how to improve this page have not met with acceptance. Philcha (talk) 18:23, 2 April 2008 (UTC)

Down to business. First, I suggest everything that's not exclusively about metabolism comes before the "metabolism" section, because that uses most of the other topics as input. If that's OK I suggest the structure is probably OK, but needs enhancements where noted:
 * History of study - probably as is, at least for now.
 * Reproductive biology. Do we have any other material? I assume nesting behaviour is off-topic.
 * Respiratory System
 * Air sacs. Need to sort out the arguments against Ruben, with refs.
 * Uncinate processes on the ribs. As is.
 * Move "Respiratory turbinates" to metabolism - there's no dispute that dinos did not have them, the dispute is about whether that places an upper limit on dino metabolism.
 * Cardiovascular system. As is, except "the structure is not necessarily tied to metabolic rate" might need to be re-phrased in view of "The crocodilian puzzle", where the researcher cited was based largely on embryology of croc heart.
 * Feeding and digestion (new)
 * The gizzard debate.
 * Chewing mechanisms. Mainly advanced ornithisicians, AFAIK.
 * Metabolism
 * [Evidence] - remove, it does nothing.
 * Growth rates. As is.
 * Bone structure. Apart from medullary bone ("Reproductive"), it all appears to be about metabolism. As is.
 * Oxygen isotope ratios. Explain "inertial homeothermy" as this is its 1st appearance.
 * Predator-prey ratios. Needs refs, this may cause content to change a bit. What's the best position? It's weak argument, but one of the earliest in the dino renaissance.
 * Posture and gait. Needs refs! Should probably be earlier, as IMO its a very strong argument (applies to juveniles, small early dinos, the lot) and one of the earliest in the dino renaissance.
 * Feathers. Needs refs, but I think there are plenty to re-use from Dinosaur and Origin of birds. How much detail? Last time we discussed this we failed to resolve which article should carry most of the detail.
 * Geographical evidence. Needs refs, probably re-use from Dinosaur.
 * Respiratory turbinates (moved because there's no dispute that dinos did not have them, the dispute is about whether that places an upper limit on dino metabolism). Philcha (talk) 20:08, 17 April 2008 (UTC)
 * Evidence for behavioural thermoregulation. Needs refs.
 * The crocodilian puzzle. Needs restructure, as it repeats the dilemmas before going to the resolution. Needs more refs. Always frustrates me, because I know that several years ago I read a book that described crocs' ectothermy as an embarrassment and proposed in desperation that crocs were secondarily ectothermic - but can I find the passage!!?? Philcha (talk) 14:16, 17 April 2008 (UTC)

Notes:
 * Dinosaur body temperature: The occurrence of endothermy and ectothermy argues for endothermy in some lineages. (Paleobiology, Winter 2003  by Seebacher, Frank) Philcha (talk) 21:37, 17 April 2008 (UTC)
 * Need help checking the refs used in A Reply to Ruben on Theropod Physiology to see if they're usable. Philcha (talk) 22:54, 17 April 2008 (UTC)
 * "Growth rates" may become its own section, "Life cycle", covering growth rates, sexual maturity and mortality tables.
 * Check out research behind Early dinosaurs crawled before they ran - suggests very young Massospondylus were quadrupeds and needed parental care. Philcha (talk) 00:10, 18 April 2008 (UTC)
 * Check whether Phylogenetic context for the origin of feathers has anything useful Philcha (talk) 19:49, 18 April 2008 (UTC)

Extensive list! "Reproductive biology" may be just a subset of something else at this point, like "growth rates". I'm not quite sure where you're going with "feeding and digestion" - could you expand on your ideas for that section? J. Spencer (talk) 03:52, 21 April 2008 (UTC)


 * Re "Reproductive biology" may be just a subset of something else at this point, I think that's an occupational hazard :-(
 * Re "feeding and digestion", I'm currently thinking of gastroliths (widely-claimed, possibly not true) and the impressive grinders / dicers of hadrosaurs / ceratopsians. I.e. tools to speed up digestion, which will also contribute to the section on metabolism. Of course looking around for refs may also turn up some other aspects, which is is either a benefit or an occupational hazard.
 * I'd be very grateful if you could help with anything where you see help is needed, and specifically (that I'm aware of):
 * Any other material about the anatomical aspects of the debate about air sacs caused by Ruben et al.
 * Any other material about the debate about nasal turbinates.
 * The explanation that dinos had short adult lives because of sexual competition (Erickson, Currie et al) does not convince me at all: the brunt of such competition falls mainly on males in just about all vertebrates, but "Sue" was only 28 at death and she was falling apart (arthritis, gout, fungal infections, etc); most metazoans have instinctive behaviours that prevent intra-specific competition from being fatal or even seriously dangerous. So we need to look for other limiting factors on dino longevity. But I haven't found anything usable.
 * Posture and gait. That seems to have dropped off the radar since Ostrom (1980).
 * Behavioural thermoregulation in sail-back dinos. And anything else about stegosaurs' plates.
 * Metabolisms of Triassic non-dino archosaurs, and when mammaliforms / whatever became "warm-blooded". Philcha (talk) 08:27, 21 April 2008 (UTC)


 * Feeding: Okay, now I see. The one author to really hit the food processing/physiology link is (surprise) Bakker; I'd have to check to see if it was used elsewhere.
 * On air sacs/turbinates: the references in "A Reply to Ruben et al." look decent; I don't see any red flags.
 * On dinosaur growth rates: It's original research at this point, but I'd guess the short lives of dinosaurs may have something to do with their being more r-strategists than K-strategists; lay a bunch of eggs, get that batch of kids going, and repeat. Under such a system, there's less pressure for adults to live as long as, say, elephants, whales, or apes.
 * The Complete Dinosaur and The Dinosauria II have good overview sections on metabolic topics, and it's common for books in the Glut series to have a section specifically on new metabolic findings. Historically speaking, there's a good overview sans refs in David Norman's Illustrated Encyclopedia of Dinosaurs (1986).
 * Speaking of which, in 1986 the arguments considered were: dinosaur posture (including the high heads of sauropods); activity levels (Deinonychus); brain size and behavior; latitudinal spread of dinosaurs; predator/prey relationships; bone histology; and the dinosaur-bird connection. Looks like the new areas are isotopes and turbinates. J. Spencer (talk) 03:33, 22 April 2008 (UTC)

Faulty reference
You appear to have specified the wrong reference for ref. 17: RuebenJonesEtAl1998 ... : it is identical to RuebenJonesEtAl1997 (ref. 16)! Smith609  Talk  14:53, 31 May 2008 (UTC)

Removed from "Crocodilian puzzle"
I'm removing
 * On the other hand, the fact that non-avian dinosaurs became suddenly extinct while crocodilians survived the K-T boundary adds further support to the theory of dinosaur's endothermy. Endothermic animals have a much faster metabolism than ectothermic ones, so that they need much more food to survive. Bigger animals also need more food for obvious reasons. Whatever the primary cause of the extinction was, it most probably passed through a disruption of food chains with the consequent starvation of animals (see the article Cretaceous–Tertiary extinction event). Some big size ectothermic animals, such as crocodilians, survived due to their especially low metabolic rate and food needs, while dinosaurs, as any other big endothermic species, probably died due to their higher food needs. Thus, extinction appears as another piece of evidence supporting that dinosaurs where endothermic animals.

because it has no refs and fails to take account of the endothermic survivors - birds and mammals. -- Philcha (talk) 09:16, 4 August 2008 (UTC)

I' am adding the cited paragraph because the references already appear in the article of Cretaceous-Tertiary extinction event. Although they were endothermic also, some birds and mammals could survive because of their lower needs of food, since they were small animals.80.102.140.84 (talk) 16:51, 4 August 2008 (UTC)Juan Casado


 * If you think the the references in Cretaceous-Tertiary extinction event support this idea, you should have added them to the text in this article too. If the problem is that you're unsure about how to format references, post the authors, dates and titles here and I'll check them out. Note that ref numbers are useless because they can change abruptly if some one add new refs or moves some text that contains refs.
 * You'd also need to take account of the fact that there's debate about whether "non-avian dinosaurs became suddenly extinct" - a question on which scientific opinion seems to change every few years. - Philcha (talk) 11:29, 8 August 2008 (UTC)

GAN??
I believe this article can be brought up to GA-level is somebody is willing to put a bit of time into referencing the last bits of the article. Nergaal (talk) 02:05, 10 September 2008 (UTC)

Possible restructure
This article was originally all about dino metabolism, but now has a fair bit of material about other aspects of dino physiology. The question is whether it's now a good idea to restructure completely so that all topics which are not exclusively about dino metabolism are in separate sections from the "Metabolism" section. The advantages are that somweone who's interested in specifically those aspects can find them easily, and it's easy to add new content under these heading even if it's not related to metabolism. The disadvantage is that the "Metabolism" section would then contain a lot of summaries of preceding content, e.g. "Some analyses of dinosaur respiration favor endothermy while others favour ectothermy. Saurischians had air sacs from a very early stage, and these became more extensive as time progressed. Air sacs are generally regarded as a sign of fast metabosisms. Theropods had well-developed uncinate processes, which suggests they were capable of sustained streuous activity, and therefore probably had high metabolic rates. On the other hand Ruben et al's conclusion that dinosaurs lacked respiratory turbinates have apparently not been seriously challenged, and the lack of such structures to prevent dehydration suggests low resting metabolic rates." I think that would be the longest of the "summaries", but there would have be others, e.g. on food grinding mechanisms in some clades but not others.

Suggestions? -- Philcha (talk) 19:05, 12 September 2008 (UTC)

Polar day
Hi, Dan Gluck, you're probalby right about the day in thwe Mesozoic being < 24 hrs. Can you provide a citation? --Philcha (talk) 09:41, 24 October 2009 (UTC)

Mammal lung size calculations in "Air Sac" article off.
Under the "air sac" section in the article, some of the proposed figures are off as to regard to what a dinosaur lung size with a mammal respiratory system.

Mammal lung size are pretty linear across the range of mammal sizes (from rats to whales), with lungs representing about 1% of the body mass, and tidal volumen 8 to 10 ml/kg. A 30 dinosaur would have the tidal volume of around 300l. The amount of air exchanged per breath varies between species - for humans, only 10 to 15% of the total lung volume is exchanged, while whales exchange around 80% of their total lung volume with each breath. Taking a relatively 20% exchange, the lung size for a 30 ton dinosaur with mammal like lungs would only be 1500l in size.

Also, the lung size in an avian respiratory system does not tell the entire story. For avian respiratory system, air sac size also needs to be taken account, and the volume of the air sac is several times greater than the lung. The combined air sac and lungh volume in birds is usually greater than mammals, which is why you don't see a bird with a weasel like frame. (For example, a 100 kg ostrich has an air sac volume of 15 liters. An equivalent sized mammal would only have a lung size of 10 l.)  —Preceding unsigned comment added by 66.51.147.97 (talk) 00:25, 2 April 2010 (UTC)

various issues
There are a bunch of things that are not "round and smooth" about this article. I can't fix them all myself (time!), so if anyone is willing help.....I'll tackle them one by one, though, so this is a to-do list for me. Please point out sources (especially popular books etc.) to me, and add points that shoulod be fixed! HMallison (talk) 13:51, 14 June 2010 (UTC)
 * Lead: should have a final sentence explaining the current more-or-less-consensus (dinosaurs = homoiotherm tachymetabolic endotherms).
 * History of study: Tornier, Hay etc. are not mentioned, in fact NO supporter of bradymetabolic poikilotherm ectothermy is explicitly cited - thus the 'changing views' in the Dinosaur Revolution are without base to change from. Owen doesn't work, nor Huxley etc.
 * Feeding and digestion: is a bit unstructured
 * Reproductiv biology: here, the entire issue of population recovery should be mentioned (Sander et al. 2010 summarizes)
 * Respiratory system: tidal volume of Plateosaurus should be added (it is certainly avian)
 * flow-through lung of crocs should be added, plus implication from EPB approach: flow-through or high degree of preadaptation is ancestral for dinosaurs.HMallison (talk) 12:59, 4 November 2010 (UTC)
 * Cardiovascular system: Seymour's and Gunga's calculations and their implications need mentioning; the "Dinosaur with a heart" is not really needed here.
 * Growth: there is plenty of new data on sauropods; should be added.
 * Metabolism: needs the terms "ectothermy, bradymetabolism, poikilothermy" explained. Also, some restructuring: the way the section is set up a reader can not step in at a sub-heading with ease, but needs to read the entire section (njo idea if this can be improved).
 * the leed is not a summary, but an introduction. This should change. HMallison (talk) 19:52, 25 September 2010 (UTC)
 * The Ruben et al nonsense about the hepatic septum must be removed, or clarified: the supposed septum is a break in the rock - duh! HMallison (talk) 21:36, 6 May 2011 (UTC)


 * You're probably right. Wikiproject Dinosaur announced 2 "improvement drives" about 3 months apart in IIRC 2008, and I was the only contributor! Since then I've mainly adapted stuff I've created elsewhere. And between other projects and RL, I'm very short of time. So I'll be very interested in what you can contribute. --Philcha (talk) 15:04, 14 June 2010 (UTC)
 * The "dinosaur with a heart" section can go; it's a remnant of an earlier expansion that I added because it was available. I always had trouble with this article because I could never figure out how to make it work structurally, so I'd pick at it for a while until inspiration ran out, then come back in a few months... J. Spencer (talk) 02:38, 15 June 2010 (UTC)
 * Hi, J. Spencer. IIRC the "dinosaur with a heart" was disreputable at the time. But I'd keep the section, as IMO one function of WP is debunking misconceptions that are spread by non-scientific "sources". --Philcha (talk) 03:41, 15 June 2010 (UTC)
 * TBH, the dinosaur with a heart was pretty unbelievable when annocunced, but given the fact that Schwitzer showed nicely how in exactly that kind of sediment iron-rich body fluids (blood) can lead to the formation of haematite concretions preserving soft tissue (blood cell?) shapes, the idea that "Willow" has a concretion in the rough shape of its heart is not that outlandish anymore.
 * So the part should stay, as Philcha points out, with claryfiying remarks, but the section does need proper data.
 * I'll try to come up with a sort of re-structuring soon. HMallison (talk) 06:42, 15 June 2010 (UTC)

Warm and Cold Blooded
Just a note that this article is riddled with 'warm blooded' and 'cold blooded'. These need to be replaced with endothermy and ectothermy throughout. Warm blooded and cold blooded have been defunct terms for at least a couple decades. They certainly don't qualify as lay-language in place of jargon either - they're just plain wrong. An ectotherm is in no way 'cold blooded' (a gigantotherm would be a warm blooded ectotherm, but so is a lizard on a hot rock), and endotherms can go through torpor that leaves them the same temperature as the background environment, so that they're not uniformly 'warm blooded' either. Anyway, just a note that this needs to be done. As it stands large chunks of this article read as if it were taken from an encyclopaedia from 1982 and the terminology needs some serious updating. — Preceding unsigned comment added by 118.139.76.65 (talk) 04:23, 9 April 2015 (UTC)

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Accurate title proposed
I brought a precision to the preliminary note, but the fact is that I really think that the title of the article should be moved to "Physiology of non-avian dinosaurs".

Who agrees with the above? Kintaro (talk) 14:34, 30 May 2017 (UTC)
 * A glance at the article indicates all dinosaurs, including birds, are covered. Some of the images specifically show birds. FunkMonk (talk) 16:12, 30 May 2017 (UTC)
 * Please, FunkMonk, note that birds are always mentioned in comparison with their extinct relatives, the non-avian dinosaurs. Physiology of birds is a different subject here since the article mainly focuses on the controversies of physiology of NON-AVIAN dinosaurs, this is why a "Preliminary note" was added in the heading of the article and this is why I think the move should be done. Kintaro (talk) 16:50, 30 May 2017 (UTC)
 * If we move it, we will have to specify every time they're mentioned in the text too. Just so someone remembers this in the event. FunkMonk (talk) 17:11, 30 May 2017 (UTC)
 * Mmmmmmmm... ok, let's keep it as it is. Kintaro (talk) 17:19, 30 May 2017 (UTC)
 * Recently many new lines of evidence have been brought to bear on dinosaur 120.28.149.140 (talk) 13:18, 22 November 2023 (UTC)

Eggshell geochemistry
Saw this article today, which seems pertinent. Peaceray (talk) 16:40, 19 February 2020 (UTC)

"During the early years of dinosaur paleontology ... sprawling ... lizards."
Owen and Hawkins both reconstructed dinosaurs with upright limbs, not sprawling ones. See the Crystal Palace reconstructions, or Owen 1841, pp. 108 and 140. Owen initially linked dinosaurs to lizards, see 1841, p. 104, without considering them true lizards, but others such as Cope would link them with crocodiles and/or birds. I suggest removing "sprawling" and replacing "lizards" with "classic reptiles." 173.73.0.102 (talk) 02:28, 14 July 2023 (UTC)


 * the physiology of dinosaurs has historically been a controversial subject. 120.28.149.140 (talk) 13:13, 22 November 2023 (UTC)
 * the physiology of dinosaurs has historically been a controversial subject particularly there thermoregulation 120.28.149.140 (talk) 13:19, 22 November 2023 (UTC)
 * Physiology of dinosaurs has historically been a controversial subject
 * Particularly their thermoregulation 120.28.149.140 (talk) 13:13, 22 November 2023 (UTC)