Hi BB, here's the Giganotosaurus sclae from the theropods chart just by itself: . The Tyrannosaurus measured 13 m, to match the uppermost size estimates. Dinoguy201:17, 3 September 2007 (UTC)[reply]
Sue is the largest known from a complete skeleton, some remains indicate T. rex that might have been a little larger. But anyway, you're right, Sue is about 42 feet long. That's about 13 meters. 13m = 42.6 ft. 12 meters would be only 40 feet. The upper size estimate for Giganotosaurus is 13.7 meters, or 45 feet long. Dinoguy200:52, 13 September 2007 (UTC)[reply]
"shouldn't the largest estimate be bigger?"
Why? The estimtes are what they are. They're coming from published ources. If that means the largest T. rex estimates are only a meter or less short of the largest Gig estimates, that's just the way it is. However, if you look at Dinosaur size, you'll notice there's no reference for the Gig estimates, so I can't confirm that 13.7m is correct. They might be diffeent once somebody checks this in the literature. Dinoguy200:36, 14 September 2007 (UTC)[reply]
The thing is that height depends alot on posture. If the animal reared up to the extent it physically could, it probably could reach 5m. I wouldn't use heights as 'found' by the scale charts in the articles anyway, as that would be original research. Dinoguy223:37, 14 September 2007 (UTC)[reply]
Hi BB, Please Stop changing sourced information. This is a diagram I created just for you, [1]. It shows the holotype in blue, scaled to known bone measurements. The original is a skeletal drawing created by a respected palaeontologist, an will have a reasonable degree of accuracy. The reconstruction of the holotype is approximatly 12.5m (a size cited in literature). However Please Note that a complete tail is isn’t known, so therefore it's exact length isn't known, it could be shorter. (with minimal mass difference). The larger specimen (only known from an incomplete dentary) in the diagram is directly scaled from the holotype. Please understand that it's almost impossible to be sure of its exact proportions unless more is known. It's entirely possible that only its head 8% larger an the rest is the same, for example. Not all individuals of a species have exactly the same proportions. So Please, be happy with the sizes in the article, which are now sourced. Steveoc 8619:21, 16 September 2007 (UTC)[reply]
Please stop changing the cited values given in this article. The cite listed for Giganotosaurus weight says 6.2 t, not 6.2-8 t. The cite for T. rex length says 12-13 m, not 12-?13 m. If you are getting this information from another valid source, that's fine, bring it up for discussion on the talk page. But changing these values is misrepresenting what the cited scientists have to say. Dinoguy203:33, 22 September 2007 (UTC)[reply]
"The original weight for the gig was 4.16-8 tonnes as soon as it changed to 6.2 can't it be 6.2 to 8 tonnes, closer to the first estimate" The first estiamte, I think, was not based on anything. It was changed when a cite was found, and the cite said 6.2, notihng about 8. A number with a source always beats all previous numbers that had no sources, which could easily have been made up. Dinoguy200:29, 23 September 2007 (UTC)[reply]
"But alot of things about dinosaurs is purely speculation,"
No, very little in science is pure speculation. This is all based on evidence, and varying degrees of confidence in our methods.
"can,t we specualte from evidence and knowledge from other theropods that giganotosaurus could have been 6.2-8 tonnes."
You could, but you'd need a good reason for thinking that. You'd need to prove that the methods currently used to estimate dinosaur weight are wrong, or that heavier specimens of Giganotosaurus exist. The you'd need to publish this in a science journal. Only then could it be added to Wikipedia.
"also i thought the upper weight limit for tyrannosaurus was 7.5 tonnes"
Not according the the scientists cited in the Dinosaur size article.
"hi BB again, how fast would you say Deinoychus could run in mph?"
Impossible to know for sure, especially since no Deinonychus trackways exist. Based on research by John Ostrom (who was the discoverer of Deinonychus and one of the all-time leading experts on dromaeosaurs), it was not very fast comapred to most theropods, and probably much slower than modern flightless birds like the ostrich (40 mph) or emu (30 mph). It's legs were modified to accomodate the killing claw, and so speed was sacrificed. See the "Speed" section on the Deinonychus page. Dinoguy216:29, 23 September 2007 (UTC)[reply]
"do you agree with me and believe the largest gig found was 13.7 metres or Steveoc 86 and believe it was 13.2 metres?"
I don't know--I haven't seen an actual published source for either. DinoData says 14m. I think these are all just vaue estimates anyway, since Gig specimens are far from complete. According to Mickey Mortimer's site [2], the holotype (original specimen) was around 12.2m, but hard to tell exactly becuse it was incomplete. All other known specimens are just teeth, except for one large jaw bone. Its proportion to the original indicates the complete animal was 13.2m (that is, around a meter longer). The site doesn't say anything about 13.7 or 14m, so I think those estimates are wrong.
"Also it bothers me if anyones working on dinosaur speed why do they just go for the T.rex?"
Those studies usually pick a 'representative' f each type of dinosaur to get a general idea of how fast large, small, and medium dinosaurs could run. They probably picked T. rex and Allosaurus for large dinosaurs because they're the most well known and well studied. Compared to them, very very little is known about Gig, so there's no reason to include it and not dozens of other large theropods.
"what are the average estimates for a T.rex and gig and i though the smallest estimate for T.rex was smaller than 12 metres as i thought that was the average size."
Average for T. rex will be lower since many specimens are known, wheas Gig is only known from 2 large specimens so its average might be disproportionatly high. Either way, quickly scanning the size figures at Theropod Database, the average length of Gig is 12.7m, average T. rex is 11.6m. Dinoguy200:29, 29 September 2007 (UTC)[reply]
Hi BB, Remember that nearly all dinosaur sizes are estimates. As Dinoguy and I said above, the holotype isn’t complete and its exact length isn’t known! I don’t ‘‘believe’’ that it was 12.2m, I do think the estimates currently in the article are more truthful to the known material. That said nether You or I have actually seen the material, we havn’t measured it for our selves, so how can any of us actually say how long it really is. So we have to trust what the scientists say. The authors of the ‘’mapusaurus’’ paper say 12.2m for the gig holotype, and there’s a 12.5m estimate in one of the refs in the article. I know not of any scientific source that says 13.7m. Steveoc 8610:30, 29 September 2007 (UTC)[reply]
"Also on the dinosaur size article T.rex is stated as 6-8 tonnes but in the theropod database it is 5.7 tonnes should you edit it or not?"
No. There's a pretty important difference between sources like Theropod Database (which list 5.7 t) and DinoData, and sources like the science journal currently listed (which list 6-8 t)--Theropod Database is an online, unpublished source. It has not appeared in a published, printed version that has been checked and reviewed for accuracy by other scientists. It's out there, so it's still ok to use, but it always gets beaten by official sources, like the one we cite on the Dino size article. Almost always, sources you find online are unofficial. That doesn't mean they're wrong, but for research to be totally valid it should go through the proper publication. I can personally vouch that Micky Mortimer (the guy who makes Theropod Database) is almost always right-on with his research. Unfortunately for everyone, none of it has been published in an official capacity, so whatever research has been must trump his, because this is an encyclopedia, not an unofficial web site. If people disagree with the official findings, they will challenge it. The thing is, getting things made official takes a lot more time than it does to publish things to the web. That might mean that Wikipedia has to be a little behind the cutting edge of dino science. But that's the way it is. Dinoguy213:47, 30 September 2007 (UTC)[reply]
Hi BB, i was refering to your persistant editing of the artical (usually without sources) but it apears there is ref for a 6-8 ton Gig, so I apologise. Please realise that the ref maybe out of date and may not be correct, note that the Dinodata page also shows older Mortimer mass estimates between 4.16- 5.2 tons quite a big difference betwneen those an 8 tons. (Mass estimates are often all over the place) .Once agian I apologise for not realising you had a ref. I also notaced that you tryed to add a 14.5m long gig estimate from the Mike Yaylor site. This estimate is most certanly wrong (and note the website hasn't been updated since 2003) refere to the diagram above basde of a fairly decent and more recent reconstruction. CheersSteveoc 8618:17, 2 October 2007 (UTC)[reply]
No, still no smoking gun evidence for feathers in Deinonychus. Also, no smoking gun evidence that Neanderthals or saber-tooth tigers had hair. But no sane paleontologist would doubt they did given current evidence from their relatives (modern cats, modern humans, Velociraptor, whatever). I can absolutely gauruntee you that after the discovery of quill knobs in V., nobody in the world except maybe creationists will doubt for a second that all paravians were feathered.
"if it did have feathered hands, face, neck and feet then surely that would cause a problem with feeding like todays birds as vultures don't have feathers on their feet,face and neck so rotting meat doesn't get caught in them so surely deinoychus sould be the same".
Why? Some birds have naked skin on their heads because of this, some don't. Saying Deinonychus surely did implies that we know it hunted and fed like a vulture, and given their vast anatomical differences (claw shape and size, shape of beak or lack thereof), there's no way we can say they were similar at all. Most carnivorous birds today have feathers on their heads (eagles, hawks, secretary birds, etc.). Most carnivorous mammals have hair on their face, neck, and arms. This whole "rotting flesh" thing doesn't appear to be a problem for wolves, lions, etc. What we know: All dromies with skin impressions have feathers on their heads, faces, even snouts, and arms/hands (wings, really). We know that dromie hands and arms could only move like wings. They might not have used their hands to hold and kill prey at all, it seems like their feet were designed to take over this role. So there's no good reason to assume they looked like vultures, and no reason at all to think they lacked wings (studies show that even with large wings, the wing claws of dromies would still be able to hold prey without damaging them, if they were used for that purpose). Like all birds, they probably did still have featherless feet. Though with things like Microraptor, we can't even be totally sure of that! Dinoguy202:13, 27 September 2007 (UTC)[reply]
"in walking with dinosaurs, utahraptors are shown shoving their heads deep into a iguanodon carcass although they were completely featherless."
WWD is simple speculation justl ike we're doing. There's no reason to think that they really fed or behaved the way they did in the show. In fact, given the very large size of Utahraptor compared to vultures, I'd say it's very likely they did not feed that way. There's no reason to think any dromaeosaur shoved their heads into carcasses like vultured rather than tore them apart like many other species.
Hi BB I saw that you wrote on Dinoguys talk page commenting on my Deinonychus pic, the reason it doesn't have featheres on its face is because it's an older pic which is wrong and I'm not sure how to remove it. If you look below it there is a newer version with feathers on the face and wings on the arms, hands and fingers. Steveoc 8612:27, 29 September 2007 (UTC)[reply]
"Hi bb again if its not to much trouble could you make me a size chart with a 14 metre giganotosaurus and a 12 metre t rex. Also do you spell t rex T.rex or T Rex"
What is the size chart for, if you don't mind my asking? It seems a little dishonest for a comparison chart to use a the lowest estimate for one species and the highest for another. If anything, they should portray both highest, both lowest, or both average size estimates. And it's spelled T. rex, always in italics, because it's a scientific name (unlike tiger or human, which are common names).
Hi, there. In case you didn't know, when you add content to talk pages and Wikipedia pages that have open discussion, you should sign your posts by typing four tildes ( ~~~~ ) at the end of your comment. On many keyboards, the tilde is entered by holding the Shift key, and pressing the key with the tilde pictured. You may also click on the signature button located above the edit window. This will automatically insert a signature with your name and the time you posted the comment. This information is useful because other editors will be able to tell who said what, and when. Thank you! --SineBot12:54, 27 September 2007 (UTC)[reply]
Hi, there. In case you didn't know, when you add content to talk pages and Wikipedia pages that have open discussion, you should sign your posts by typing four tildes ( ~~~~ ) at the end of your comment. On many keyboards, the tilde is entered by holding the Shift key, and pressing the key with the tilde pictured. You may also click on the signature button located above the edit window. This will automatically insert a signature with your name and the time you posted the comment. This information is useful because other editors will be able to tell who said what, and when. Thank you! --SineBot15:13, 2 October 2007 (UTC)[reply]
Yes, I remember hearing about some study a few years ago which said carcharodontosaurids used a "slashing" bite while tyrannosaurids used a "crushing" bite. They speculated that maybe carchs were eating sauropods. There's no actual evidence for this though, not like we have for tyrannosaurids eating hadrosaurids. It's just based on the fact that there were a number of large sauropod species in the same environment, but that doesn't really mean much--lions don't usually eat adult elephants. My opinion is that at most, they probably hunted baby sauropods. One new study showed that titanosaur armor wasn't useful in adults and got more "spongy" as the animals grew. This implies that the presence of armor in titanosaurs was mainly to protect them while they were young, when the armor was harder and denser. So gigs might have partly fed on baby titanosaurs. Dinoguy223:24, 2 October 2007 (UTC)[reply]
Hi BB, sorry for the delay in responses. My computer crashed last week, so I've only been able to check my stuff online sporadically. Hopefully I'll have it back from the shop by next week... Anyway, Giganotosaurus comes from the Rio Limay formation, so it lived alongside the titanosaurs Argentinosaurus and Andesaurus, as well as the diplodocoid Rebbachisaurus. The only non-sauropod hebivore was Anabisetia, an iguanodont. There were also other carnivores, namely Mapusaurus and the smaller Ilokelesia (can't assume gig only ate the plant eaters!). I'd class a 'baby' titanosaur for these purposes as anything small enough for a gig to prey on it without serious risk of injury (with predators always, always avoid unless they're totally starving). Not sure what size limit the paper said titanosaur armor was effective up until, however--that might be a better benchmark.
I've heard of evidence that T. rex hunted in packs, but this is based mainly on other kinds of social behavior. For example, some rex had evidence that they had bad wounds that were healed, and that implies they were brought food or cared for by other animals. I don't think there's any actual evidence that they hunted in packs, however, but they probably had some kind of social behavior. There's no real evidence that Mapu hunted in packs, however--just the fact that a lot of them were buried together, but that could be anything. Similar evidence from raptors was recently shown that they were mobbing on carcasses, not hunting in a pack. As for other carchs, it has been suggested that they hunted in packs to bring down sauropods, because they were the dominant herbivores in that environment. But that evidence was based on Mapusaurus (which has been talked about in rumors and such for over ten years before it was fianlly described. Those rumors got way out of proportion, like, for a while the dinosaur eventually named Mapusaurus was widely believed to be much larger than gig and was famous as the "undescribed largest theropod").
Either way, it's never a good idea to add stuff like this unless it's backed up in actual papers. A lot of unofficial speculation goes on in paleontology that doesn't belong in Wikipedia! Dinoguy201:44, 10 October 2007 (UTC)[reply]
Hey BB, few responses...
"Also ages ago i was wondering on edmontosaurus speed and although someone gave alot of info nobody answered my question so would yopu say edmontosaurus could run at the same speed as t.rex or faster/slower?"
I think the most often cited study about this is by Hutchinson & Garcia (2002). They calculated that T. rex was not very fast (top speed of 11 mph), but was faster than the hadrosaurs and ceratopsians it hunted (this would include Edmontosaurus, Triceratops, etc.). The newest study that came out this year says 18 mph for T. rex, so if Hutchinson & Garcia are right about relative speeds, that would mean edmontosaurs might have been a bit faster as well, but still not as fast as rex. These are all based on adult rex as far as I know--juveniles had limb proportions like ornithomimids and were probably pretty fast.
"Also when you said other t.rex may have brought bck carcasses for wounded ones i believed t.rex could scavenge carcasses to survive or had a good enough immune system to overcome such wounds (knowing T.rex's lifestyle it could have been wounded everytime it went hunting)!"
Imune system wouldn't help in recovering from wounds except to fight infection, but we have no way of knowing what that was like. We don't know very much at all about rex's lifestyle, but we know enough about how all other animals behave to know that it probably did not get injured on every hunt! In almost every case, an injured predator is a dead predator, and rex was just a regular animal like any other, so this must have been true for it too. Predators are always cautious and try not to "fight" with prey too much. If it looks like they might get hurt, they'll back off. The fact that a rex got hurt and lived is very, very surprising, which is partly why the social hypothesis had to be thought up. Other theropods weren't so lucky--look at Big Al. It has a lot of evidence of disease and injuries, and they finished it off at a young age.
"Hi BB again was was wondering about that time i asked you about theropod height and looking at your scales i may be wrong but it looks like they are in a runnng pose, slightly crouched and if they were standing normally or walking they would be taller i could be wrong but i want to know what you think to this."
Oddly enough, based on what I know about how their legs worked, I think they'd be shorter in a standing pose! Dinosaurs could not extend their knees very much, and in the running pose size charts, the knees are all at the very maximum amount they could possibly stretch. The knees would be flexed a lot more if the dinosaur were standing, which I guess would make them shorter overall (only by a foot or two, but still shorter). Dinoguy215:15, 22 October 2007 (UTC)[reply]
"you stated that rexs didn't like to fight with their prey but would they have had a choice? Triceratops and torosaurus are far from defenceless although rexes may have gone for younger dinosaurs and angry mother is still a fierce enemey to be reconned with don't you think, also either its just me or is it that with the fossil skeletons of theropods like the pictures of sue and the gig fossil picture on the gig article that they seem to be taller than in your size scales, it probably me but again whats you view on this?"
Well we know from fossil evidence that rex were hurt in the leg by a Triceratops in at least once case. It definitely happened, just probably not that often if the rex could help it. They most likely did go for juveniles but picked their battles to minimize risk, just like every predator alive today. That doesn't mean it wasn't still risky! Predators make mistakes and get killed or wounded (and if wounded, often starve to death). All the photos of gig and rex skeletons are museum mounts, and if you look closely you'll notice they're up on 3 or 4 foot platofrms, making them look big compared to the people standing next to them. The photo in the gig taxobox is even more misleading because the person standing in front of it is a little kid. Dinoguy222:43, 22 October 2007 (UTC)[reply]
Hey BB, few replies:
"Hi me again i was wondering about rex speed and when it was thought onl t be at 11mph it stated that this was still faster than triceratops i always thought triceratops speed was 15 mph also would have thought edmontosaurus would be faster/same speed as they were around 12,13 metres meaning they had the same/a bigger stride length thn most rex and should have been able to go faster as they were only 4.4-5 tonnes while rexes were 6-8 tonnes."
I don't know who said Triceratops was 15mph, but my bet is that the newst studies would argue against this. They didn't calculate actual speed for all the animals, just relative speed, i.e. what was faster than what. So if you agree with that study, if T. rex was 11mph, because of biomechanics, Triceratops had to have been less. As for stride length, T. rex certainly had a bigger one than any hadrosaur, due to its lower leg/upper foot ratio, which is the important thing to look at for speed, rather than overall length of the leg.
"Hi BB again this is just a thought that i want your view on, as young hadrosaurs were lighter than their parents would they have been able to run quadrupedally? Also would adult hadrosaurs be able to run quadrupedally, not running at their top speed bipedally just a very slow quadruped jog?"
I've seen conflicting studies on how often hadrosaurs moved quadrupedally. It probably varied by age and species, as you figured out. My guess is that juvies would have moved bipedally more often, adults more quadruped (because of their size). I don't think there's any evidence that hadrosaurs could "run" at all, more like fast walking (running means both feet leave the ground at the same time). I doubt they could even gallop, as some people think ceratopsioans could. They weren't built that way. But if I had to guess, I'd say the smaller species would be better than, say, a sauropod-sized lambeosaur. Most things I've read, though, suggest that when moving fast, they would have been bipeds. Quadruped movement would have been for slow speeds only. So I doubt any ran quadrupedally. Dinoguy200:56, 29 October 2007 (UTC)[reply]
Hey BB< yes got my computer back last week. Sorry I haven't replied, but I'm havig trouble keeping track of your posts on my talk page--you should separate new topics into paragraphs and sign your comments with 4 ~s. You raise some good questions concerning speed in relation to wieght--I don't know the answer, and I don't think anybody does. I don't know of any studies that have examined questions like this yet. I hadn't seen Arthur's gig drawing, it looks quite good! Thanks for pointing that out. I don't think the current one's tail is too flexible, however--carnosaur tails weren't stiff as a rod, in fact that was only true of droameosaurids and some other earlu birds/maniraptorans. The tails of other tetanurans were not as flexible as, say, a lizard, but could still bend a good deal. Dinoguy212:50, 10 November 2007 (UTC)[reply]
Hey BB. You're right, the sample size for gig is much smaller than for rex or Allosaurus. In those two cases, we can probably be reasonably sure that we know what the 'average' size was, and which individuals are above or below average (for example, things like Sue and C-Rex were big by T. rex standards, Big Al was small by Allosaurus standards. We can't be so confident yet for Gig. However, we can compare it to its relatives. Mapusaurus is known form a whole range of sizes. The largest estimates are based on the largest fragments of bone--most specimens are smaller, so we can be pretty sure that the gig-sized Mapusaurus was on the upper limits for size. It would be reasonable to assume the same is true for gig, and the few gig specimens we have represent the upper size limits. But there's no way to be sure right now. Dinoguy2 (talk) 01:23, 17 November 2007 (UTC)[reply]
I think a safe assumption would be that gig was slower than T. rex (especially the smaller or not fully grown individuals), since tyrannosaurs in general had more ornithomimid-like leg proportions than carnosaurs. C-rex was estimated to be 14m, but I think that was an overestimate, not sure how big exactly it really was (I don't think it's been published yet?), probably about the same size as Sue.Dinoguy2 (talk) 23:40, 17 November 2007 (UTC)[reply]
Hey BB! I don't know what the stride length is for gig, or if it's ever even been calculated, so I couldn't tell you. Do you have a link to Steveocs graph so I can see where the height difference comes from? Dinoguy2 (talk) 21:06, 20 November 2007 (UTC)[reply]
Ah, ok. In Steveoc's diagram, the back is angled upwards slightly more, so the height difference is due simply to the pose of the animal. This is why when scientists measure height in dinosaurs, it's always to the hip, not to the head, since that's the only part of the body that doesn't vary, at least while standing. If you look at both my and Steve's diagram, the hip height in both is 3.5 meters, so they are the same height in reality. Dinoguy2 (talk) 20:10, 21 November 2007 (UTC)[reply]
I think T. rex hip height estimates re about the same as gig--3m at the hip, around 3.5 for the really huge end of the scale (I think Sue is around 3.5), Dinoguy2 (talk) 22:24, 22 November 2007 (UTC)[reply]
Probably a bit bigger (4m?), but no way to tell since the 14m specimens are only known from a jaw bone, nobody knows what the leg proportions would be. Dinoguy2 (talk) 17:16, 23 November 2007 (UTC)[reply]
Hey BB, there's some evidence that large dromaeosaurs lived in groups (based on footprints). Not much evidence for other types of dinosaurs, though. There are lots of instances where a lot of predator bones/teeth are found together, but these are more likely predator traps or mobbing behavior. So there's no solid evidence for pack hunting in any dinosaurs, though they might have all ganged up on prey without actually cooperating (there's evidence they were killing each other as well, which can hardly be called cooperation!) Dinoguy2 (talk) 20:24, 27 November 2007 (UTC)[reply]
Yes, very interesting! However, a lot of people on the DML are skeptical that the bigger leg muscles mean it can run faster (the example they used is that elephants have much larger leg muscles than ostriches, but ostriches can still run much, much faster). Still the mummy is really cool (especially the idea that they can figure out skin patterns based on scale size), can't wait for the show on NatGeo. Do you know for sure that it's an Edmontosaurus? I hadn't heard it referred to a specific genus yet. Dinoguy216:57, 4 December 2007 (UTC)[reply]
Hey BB, it's impossible to say for sure of course, but I think a safe bet would be that the new findings in that hadrosaur apply to all hadrosaurines, at least (assuming that's what subfamily it's in). Whether or not the idea that bigger leg muscles = faster in hadrosaurs still needs to be tested too. Again, elephants have much larger leg muscles than ostriches. Merry Christmas! Dinoguy2 (talk) 15:28, 24 December 2007 (UTC)[reply]
Hey BB, I've always seen that in arguments about JP3 as well. No study has been done on Spino bite force... in fact, I don't know of any bite force studies other than T. rex. I don't know of any reason spinosaurids would have had poor bite force. Probably not as good as rex, but for all we know it could have been strong. No way to know until somebody studies it. The whole "Spino had weak bite force" thing seems to have been completely made up by JP fans, in my experience (usually the same ones who constantly deny it was larger than rex, too). Dinoguy2 (talk) 00:06, 7 December 2007 (UTC)[reply]
Yes contrary to what jurassic park fans may say Spinosaurus would have had a pretty strong bite! You have to remember that cretaceous fish and prehistoric fish in general, were heavily armored compared to today's specimens. One article that I recall(I can find it if you want)mentioned that biting through such prehistoric fish would have been akin to biting through chain mail. Other than that spinosaurus had a well developed secondary palate like crocs as I recall, which would have made its skull pretty resistant to torsional stresses and such. Not as powerful a bite as t.rex of course but strong in its own right spino's bite force would be.DinoJones (talk) 21:59, 25 December 2007 (UTC)[reply]
Hmm, can't seem to find any cites for the T. rex leg wound--I'll ask around. Maybe it's not published yet. Here's the new size chart: Dinoguy2 (talk) 17:35, 18 December 2007 (UTC)[reply]
I was surprised to see Andrewsarchus come out that small as well, but I knew it would be as soon as I read the info in the wiki article regarding its proportions. It's skull is not even a meter long, and weight estimates based on relatives are less than the average size of a grizzly bear! Any claims that it was the largest land carnivore are clearly exaggerated. Kodiaks and polar bears are larger, it's just that Andrews has a relatively long skull. Dinoguy2 (talk) 20:05, 18 December 2007 (UTC)[reply]
"We model a quite small tyrannosaur (FMNH PR 2211 I think), which should be the same as an ornithomimosaur I'd expect; about twice as good at running as an adult Tyrannosaurus."
"Tyrannosaurus are very close in build to ornithomimids. I mean, they look the same but have more robust bones. Maybe those are the animals we should be comparing tyrannosaurs too???? Paul's 1988 book comes to mind."This is all missing the point of the research. Anatomy matters a lot, but so does physics. The best we can do is try to evaluate their importance using scientific methods.
Actually, as that last one points out, Greg Paul probably talks about this in Predatory Dinosaurs of the World. You might try looking there if you have/can find a copy!
"Also the newest speed theory for a rex is 18 mph, what makes this estimate more reasonable then the theory of it moving 24-25mph or should the latter not be ruled out( it seems a little "unfair" on the rex that hadrosaurs get to wizz of at 28 mph)"
It depends on which papers methods you agree with more. I personally think the 18mph estimate is better, given the mass of the animal.. but maybe T. rex was a lot lighter than we think, in which case the faster speed makes more sense. As Hutchinson says, it all depends on physics, and changing any of the numbers in the equation changes the whole thing. I also doubt hadrosaurs could run 28mph just because they had big thigh muscles. I'll wait to read some kind of actual study, but I have a feeling the TV show sensationalized that for the sake of an exciting story.
"wouldnt it be easier and safer to live and work in packs? Although the deinonychus find shows cannabalism, couldnt that just be a fatal confrontation with another pack trying to steal the tenontosaurus meat?"
Anything is possible, but three things need to be considered--evidence, inference, and parsimony. We look at the evidence, compare the evidence with known behavior of real animals either related to Deinonychus (birds) or that we think lived similar lifestyles. Then parsimony comes in--the basic guideline in science that the simplest explanation is best until new evidence disproves it. The idea of competing packs of Deinonychus engaged in some kind of primate-like turf war doesn't make much sense in any of these criteria. Is it possible? Yeah, but there's no reason to think so. The best explanations are that either they were mob-feeders like many modern birds, or that they have some kind of very loose social structure, like other modern birds. Hawks and such may travel together and assist in kills, but this isn't really a "pack", which is a completely mammalian thing. I think given the studies on mob behavior and new footprint evidence of social groups, the best explanation is that they travelled in loose "flocks". But this probably varied by species, and there's still no evidence that they coordinated in any way on kills. This also happens to mesh with the fact that they were bird-like. My personal feeling is that dromaeosaur behavior was more like vultures than wolves, though they probably weren't pure scavengers.
And no, I don't think it's always more efficient to work in packs. 99% of modern day carnivores don't do this, even when they're very close relatives (foxes vs wolves, lions vs. tigers or any other cat really...). Even in the same species, cooperative hunting might happen occasionally or by accident, like hawks, but they spend most of their time hunting alone. However, you're probably right that it's safer--many modern birds live in flocks for safety reasons, I think. Maybe dromies were the same way. Dinoguy2 (talk) 22:58, 7 January 2008 (UTC)[reply]
That assumes they lived in flocks all the time, and didn't just tend to travel in the same direction when a bunch found themselves in close proximity. At the moment we only have one single set of footprints from a giant dromie species to go on. The same area preserves footprints from much smaller dromies or troodonts that show typical, random movement you'd see in other types of birds. So even if one species lived/hunted in flocks, there's good evidence that another didn't, or had a much looser 'social structure'. It probably varied greatly by species, which means it's even less scientific to propose such behavior for any one, like Deinonychus. Dinoguy2 (talk) 20:13, 9 January 2008 (UTC)[reply]
"Velocirator's speed was 25 mph and deinoychus was bigger and had a longer stride length, would deinoychus have been faster than velociraptor? Also what science journels do you read fo dino info as i was wondering if i could purchase them anywhere."
Who said Velociraptor was 25mph? The only speed estimate I've ever seen published for any dromaeosaur (though I could be forgetting something obvious) is the one I recently added to the Deinonychus article--based on footprints that probably belong to Deinonychus, it's walking speed was about 6mph. I'm not sure if Velociraptor has a significantly different foot-lower leg ratio, that needs to be taken into account as well as stride length.
For dinosaur info I basically just read online discussion groups like the Dinosaur Mailing List and DinoForum, and if I read about interesting papers, I can go look for them. Most are available online nowadays (just type the citation into google or google scholar) but you need to access them from a library or university internet account (or go to a library that carries the journal you're looking for in print). There are so many it's not really practical to just brows them for info, which is why keeping up online helps me out a lot. Also, if there's a paper you really want to read, ask around at Wikipedia, maybe somebody here has it and can email it to you! Dinoguy2 (talk) 16:25, 20 January 2008 (UTC)[reply]
Oh, the speedy Gonzales Compsognathus paper! From what I've read that has a lot of technical problems with their results. See the discussion starting here: [3] I'd take those speed estimates with a big dose of salt. Most important part:
"Regardless, it seems to me that some parameter fed to the evolutionary algorithm resulted in the model "expecting" mass to predict speed in a linear fashion (which is dubious to start with), and in an inverse manner (which is even worse)."
In other words, because of an apparently major calculation error, their model finds that the smaller an animal is, the faster it goes. If this were the case mice would be faster than cheetahs. Worse, it works inverse, meaning that as an animal gets bigger, it gets slower, until some point where it starts getting faster again, so that giant animals (like T. rex) are also extremely fast! This is pretty clearly just plain wrong, based on observations of how modern animals work. Dinoguy2 (talk) 22:06, 20 January 2008 (UTC)[reply]
Hey BB, you raise some interesting questions about gracile/robust rex and prey size. I don't know the answer, and I don't think anyone has ever done studies like that. There's not much speculation about the reasons for gracile/robust at all--what you're suggesting is sub-species of T. rex that specialize in different prey. I'm not sure what type of study could be done to test that, but it's a good idea for somebody to do as a Masters thesis someday! I also don't know about distribution of various sized prey--rex had a pretty huge range (Canada to New Mexico at least), but then again, a lot of the big prey items are thought to have migrated (maybe that's why rex had such a big range), so my guess is that the prey size would depend on the season, but would otherwise be pretty uniform, if you can call it that, with big prey items coming in and out of areas at specific times of year. I think the fact that hadrosaur nest sites tend to be found in "high country" far from large water bodies might support this, but again, that's just a guess.
As for which hadros lived with rex, Edmontosaurus was far and away the most common. I think it's a safe bet the newest dino mummy is and Edmont. However, I can't remember if it was found in the Hell Creek or Judith River formation. If it was Judith River, I don't think Edmontosaurus lived there along side rex--the hadrosaurs known from that one are Brachylophosaurus and Lambeosaurus. In that case, Brachy would be a safe bet, as it's another hadrosaurine similar to Edmont, and it would probably compare well to the Brachy mummy "Leonardo" that was all over the news a few years ago. But we won't know for sure until it's published. Who knows, it might be a new species.
And you're right about the theropod scale diagram--I uploaded a new version a few weeks ago. All the measurements should be the same, though I used better skeletals for some of them (Spino and Theri are all new). The main reason was that I wasn't happy with the head size of Spino in the old one--it didn't match up to published sizes. So I used a new model I made based on WP:Dino-approved images (it's the one I made for the comparison by suborder). I also made Carch bigger, because the new species shows that some did grow longer than rex, despite Mortimer's estimates. If you stretch out Gig and Rex into perfectly straightened poses, Gig would be about 13.5 or 14m in the new one and Rex would be 13. Carch would be 13.5, which is good because I scaled it based only on the skull (tried to make it exactly 1.6m), so the proportions in that particular illustrations ended up giving an animal the same size as the upper published estimates. Hopefully that means the whole thing is more accurate than the last one :)
(Oh, and you may notice I also added a throat pouch for rexy, which is known from skin impressions. Not sure if they're published or not. Same deal with the Edmontosaurus in the ornithopod scale). Dinoguy2 (talk) 00:09, 12 January 2008 (UTC)[reply]
"in dino autopsy the hadrosaur running position was with its tail raised in the air and its front body closer to the ground with its arms tucked in, do you know what positions maniraptorian, tyrannosaur, and carnosaur theropods would have been in while running?"
No, the methods they used to get that pose were a unique computer modeling program, if I remember from the show. It's possible they modeled other types of dinosaur but I don't know--remember the show was just like an 'ad' for the real study which will be published some time in the future, that will contain all the actual scientific info.
"Also the hadrosaurs was fast due to muscles in its tail, is there evidence of this in other dinosaurs?"
Don't think there have been studies on that, and again, the reaction to most scientists I've heard about that show is that it's very questionable whether or not big tail muscles will = fast running. We'll have to wait for the paper to evaluate their methods.
"Lastly due to deinoychus sickle claws, the running speed has been reduced to no more than 20-25 mph"
I wouldn't say reduced, I don't know of any studies that ever said they could run faster than that. It's not due to the sickle claw directly, it's due to the short foot, and the foot may have been shorter, in turn, because of the sickle claw. It's just the simple formula of comparing the ratio between the foot and lower leg. Dromies all have a poor ratio in that department, but it varies. Dromies as a whole were among the slowest theropods, based on that ratio. Other dinos with sickle claws, like troodontids and Archeopteryx, may have been a bit faster, but I'm not sure. Out of curiosity, which study estimated Deinonychus at 20-25mph? Dinoguy2 (talk) 01:19, 18 January 2008 (UTC)[reply]
Hey BB! First of all, I don't think there's any official source calling the JP raptors "Deinonychus" or "Velociraptor antirrhopus"--this was made up by fans. In the book they're V. mongoliensis, and in the movie they're just Velociraptor. Writing something like Velociraptor antirrhopus nublarensis is kind of a lie, as Paul never used these JP "subspecies"... the fanwanking on that chart is pretty impressive. And yes, they're way too big to even be Deinonychus. Closer to Utahraptor size, but the proportions are still way off. A Utahraptor of that height would have been about 20ft long, as the tails on those JP creatures are generally too short. As for your speed questions, I've pretty much told you everything I know about dinosaur speed, and that's in the neighborhood of all anybody knows. This is a very inexact science right now, and very few studies have been done. Further, usually only one 'representative' of each group is studied, because the idea is to just get a general idea of what dinosaurs of certain sizes and body plans might have been capable of. When somebody published speed estimates for say, Edmontosaurus, the implication is that most other hadrosaurs of that size would have been around the same speed, give or take, blah blah blah. It's more a tool to provide a general idea that very specific data points in most cases. I don't really have an opinion on which are more reliable, but my gut feeling is that the slower estimates would tend to be more correct for such massive animals. Unless the weight estimates are too heavy, which is also a possibility. I seriously doubt a 25mph T. rex if it really weighed 8 tonnes, but if it weighed 5 or 6 as the low-end estimates have it, that's another story. Dinoguy2 (talk) 16:10, 23 January 2008 (UTC)[reply]
Hey BB, thanks for the offer on the squamate scale charts. Haven't quite gotten to that yet, as I'm mainly focused on dinosaurs at the moment and nobody's really requested anything specific (just things like varanids, mosasaurs, etc.) A mosasaur chart would probably be first on the list if I get to it, but I want to re-do Deinonychus first. The problem with Arthur's image is that it's not a straight-on lateral view, there's a bit too much of a skewed perspective there. I'll probably just take an image of another dromie and change the proportions a bit. If you have any good photos of komodo dragons in lateral view, it would b great if you could upload them to commons. Once they're on there, they're free to use, plus they'd be cool for the articles. As for Utahraptor, I did make it smaller than in the other image, on purpose--I've heard that new studies on it will show it was smaller than usually thought, so I scaled it to the lowest available size estimates from current papers. The fact I used a different base drawing may also skew the proportions a bit. I don't want to re-do the scale in the current Utahraptor article, though, until the paper is officially published and I can get some more solid size data. Dinoguy2 (talk) 22:28, 23 January 2008 (UTC)[reply]
Hey BB, good questions! We don't know the extent of feathers on the faces of any raptors except Sinornithosaurus. If you take a look at the "Dave" specimen (the really beautiful one articulated on a single slab), you can see the feathers come most of the way down the face and cover about 3/4 of the snout, with the end of the snout naked. This is assuming the feathers are preserved perfectly in life patterns of course, but it doesn't look very disturbed to me, so I think it's a safe bet. As you noticed, the amount of feathers on the face vary from species to species in modern raptors, so it's really up to artistic interpretation. I don't know if this thoery has been published, but I remember people discussing the possibility that early birds and raptors, etc. retained clawed hands with flexible fingers partly as a grooming aid. So pack hunting isn't needed to expalin how they groomed--they had more and better tools (wing claws, teeth) for grooming than most modern birds do (also, are you sure cheetahs are pack hunters? I thought they hunted solo, but that's just based on what I've seen on TV, haha). The large raptor prints from China--we don't know what made them. They're from an animal the size of Achillobator, but Achillobator lived in a later time period. There must have been a similar, slightly earlier species that hasn't been discovered yet. Oh, and I also learned recently that a series of footprints were found in Canada that probably belonged to Deinonychus. I haven't been able to get the paper (too old to have been put online) but as far as I know it was travelling solo. Estimated speed was 6mph, but it wasn't in a full run (just a reasonably fast walk). Dinoguy2 (talk) 18:32, 25 January 2008 (UTC)[reply]
Well, it certainly didn't get off scott free in the fighting dinosaurs, but isn't that evidence that they didn't hunt in packs? All predators could benefit from pack hunting--most still don't, simply because they never happened to evolve that behavior. All predators could probably use the ability to fly too, but that doesn't mean wolves will ever evolve wings ;) I'm working on the Deinonychus scale now, should have it up by tonight. Deinonychus fossils haven't been found in Canada yet, but the prints are from the same time period, and it's known from Montana which is probably close enough. They didn't have border checks back then ;) (Maryland is a mid-atlantic state of the US, not in Canada by the way). Dinoguy2 (talk) 23:12, 25 January 2008 (UTC)[reply]
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Hey BB, sorry it took so long to get back to you, been busy this week for a change, haha. That is a possible scenario for the fighting dinosaurs, but without any evidence we can only speculate, and in science it's best to go with the simplest explanation available. That is, if there's no evidence that other raptors (or protos for that matter) were involved, there's no good reason to assume that, though it's always possible. Heck, how do we know a pack of Protoceratops didn't attack the Velociraptor, trying to get its eggs or something? ;) I'll put Smilodon on my list for size graphs, actually I might do that before the squamates, it sounds more fun! There are some very good high-res images of the "Dave" specimen here: [4]Dinoguy2 (talk) 18:01, 31 January 2008 (UTC)[reply]
Slimodon is almost done, will post it soon! Senter 2006 is this paper:
Senter, P. (2006). "Comparison of Forelimb Function Between Deinonychus And Bambiraptor (Theropoda: Dromaeosauridae)." Journal of Vertebrate Paleontology, 26: 897–906.
It's a very comprehensive anatomical study of dromaeosaur forelimbs, how they could move, and how they couldn't move. I can send you a copy too if you'd like, just drop me an email! Dinoguy2 (talk) 21:49, 7 February 2008 (UTC)[reply]
Hey BB, that sounds like the old school 1970s depiction of Deinonychus that was very popular before more detailed studies were done of how dromaeosaurids were built (back then they were thought to be much more carnosaur like, IIRC). It was also done right at the beginning of the dinosaur renaissance, and I have a feeling that's why it is more "upright". I wonder if people were trying to fit the new ideas about speed, non-dragging tails, etc with old ideas of an upright posture. This is the most up to date skeletal reconstruction of Deinonychus that's been published: [5]. Basically, anything that differs very much from this is old and outdated. Dinoguy2 (talk) 18:39, 9 February 2008 (UTC)[reply]
No, I used a modified version of SteveOC's Utahraptor drawing for the stencil, but the proportions should be the same. I don't know why it comes up to a human shoulder in those other diagrams, it's hard to tell without looking at them. I've seen two mounted Deinonychus skeletons in person, and they certainly don't come up to the shoulder (except the one at the AMNH, which is jumping ;) ). Again, without seeing the diagrams you're talking about, my guess would be that the proportions are wrong. If you took an outline with a tail that's too short and made it 3.4 m long, it's obviously going to end up being taller and overall too large. One way to check if a diagram is right is to use measurements other than overall length. What is the approximate skull length and hip height in the diagrams you're talking about? Deinonychus should be 1m at the hip and have a 0.4 m skull. If they're bigger than that, then the proportions are wrong and therefore the scale is wrong too. Dinoguy2 (talk) 14:29, 10 February 2008 (UTC)[reply]
Well 1m is a generalization, the only published height estimate I know is 0.87, which is 'around' 1m. Also, the legs in the scale I made are significantly flexed, so it may actually be too tall. I think hip height is just measured by adding the lgenths of the leg bones, but the animal definitely did not stand with legs perfectly straight--in fact theropods couldn't extend their knees very much at all. I'm not sure if this is taken into account when estimating hip height or not. Dinoguy2 (talk) 00:49, 12 February 2008 (UTC)[reply]
Thanks! I haven't read the paper about the crampon style dromie claws yet, but from what I've heard it's probably a good possibility. The authors apparently suggest they were used in climbing/clinging to the side of large prey. I have to wonder why they didn't factor tree climbing into the equation, which would make a lot of sense for the smaller species. Dinoguy2 (talk) 17:52, 13 February 2008 (UTC)[reply]
Hey BB, for some reason that DinoForum link stopped working. You can get to it now through here:[6] Just from what I remember, the only giant theropod eggs come from Mongolia. Some have been attributed to therizinosaurs, and at least one has turned out to be from a giant oviraptorid (hey, I wonder if it could be Gigantoraptor!). Here's a link: [7] I remember hearing something about possible tarbosaur eggs too, but these might have turned out to be therizinosaurs as well. I haven't read the papers about therizinosaur nests yet, but from the pics I've seen it looks like they were in clutches of several eggs but not as many as, say Citipati, Maiasaura or Troodon. Dinoguy2 (talk) 14:42, 16 February 2008 (UTC)[reply]
Hey BB! Sorry bout the late reply, missed a few of your posting due to others posting at the bottom of my page, and I've been pretty busy at work. I'll see if I can answer everything I missed...
The only other paper I can find in a quick search on carnosaur bite force is Rayfield et al. 2001. They studied the bite force of Big Al, and found it was lower than T. rex or an alligator (so less than 13000n I think?). But they also found that the skull was built stronger than what you'd expect for that bite force, and that they probably used fast, high-impact attacks rather than grappling attacks. I've seen the bite force for Gig listed online as 1500-3000n (probably confused n and psi, not sure how to convert those myself) which makes sense given the allosaur estimates but I can't find a source for that, could just be somebody's educated guess.
I used GSP's Giganotosaurus skeletal for the outline. It was out of the files I've collected online over the years, not sure where/if it was published. Hopefully just using the outline makes it somewhat ok! :x
Mesozoic Snow--there's a good thread on this on the DML, starting here:[8]. Snow doesn't fossilize, but freeze cycles leave behind coarse, polygonal soil in the rock. I don't think anybody has studied to see if this is present in any dino formations. The best we can say right now is that dinos at the north and south poles (Antarctica/Australia, Alaska/Northern Canada) would have seen some snow, assuming they didn't migrate to avoid it. Exactly how much is impossible to tell. I don't know if T. rex range extended far enough north to have been in the snowy areas. There probably wouldn't have ever been snow in Montana or southern Canada back then.
I'm not sure about the warm-blooded thing. I think the evidence right now points to most dinosaurs being somewhere in between "warm" and "cold" blooded. They grew fast, like warmblooded animals, but other features of their bones look cold blooded. Even early birds have coldblooded-looking bones, so full bird-style warm bloodedness probably didn't evolve until fairly advanced flying birds above Enantiornithes. Dinoguy2 (talk) 04:44, 4 March 2008 (UTC)[reply]
Not sure which rex bite force numbers are best, haven't read those papers. But based on what I have read it's probably on the high side. Rex was built to eat animals bones and all, you need a big bite force for that. Dinoguy2 (talk) 21:58, 6 March 2008 (UTC)[reply]
I don't think the evidence is nearly good enough to say for sure, but it does look like most dinosaurs had some type of parental care. Maiasaura is the classic example, but there are sauropod footprints showing protection of younger individuals in the middle of the herd, and evidence that oviraptorids fed their young in the nest. Some dinosaurs like Psittacosaurus have often been found with flock of young preserved around them, and this might even be related to the burrowing behavior of some small ornithischians (most famously Oryctodromeus). I don't think there's any evidence of whether males or females cared for the young, but in modern birds it's usually both, for what that's worth. Dinoguy2 (talk) 20:58, 11 March 2008 (UTC)[reply]
Hey BB! Your idea about older gigs being larger works in theory, but there's a lot we don't know. For example, T. rex is very well known with a lot of specimens, and we can pretty easily estimate age-related growth curves. Gig is not nearly as well known, I don't think anybody has tried to estimate how old the few known gig specimens were. It's possible the big ones were just as old as Sue, or that Gig had different growth patterns than Rex, reached maximum size at a different time, etc. There are too many variables to say that a very old gig could have been 15m, but it's possible in theory. What we'd need is a study comparing rex and gig growth curves (like this one [9]), but that may not be possible given the poor sample size for Gig. Maybe for Mapusaurus though, which is known from a wide range of sizes/ages.
I don't think any allosaur speed tests (you mean how fast they could deploy the axe-like bite?) have been done. I'm also not too up on my bite force measurements, so I'm not sure which estimates are good and which not so great, I'd have to first read the papers and then do some learnin' about exactly how these tests are performed. Do you have citations for the gig bite force of 3 tonnes I could read? Dinoguy2 (talk) 23:50, 29 March 2008 (UTC)[reply]
Hi BB, the 18m megalodon estimate is listed in Renz, Mark (2002). Megalodon: Hunting the Hunter. It would be nice if the Megalodon article listed whatever primary sources this book used, but since that size was part of the request I'll take the cite's word for it for now. As for allosaur bites, I guess it's possible the axe-attack could have broken bone the way hitting somebody with a bat can break bones, but we're talking fractures here--tyrannosaurs jaws were designed to crush up, not just break, bone. For this they had special d-shaped teeth. If an allosaur or other large theropod attempted such a bone-crushing move, it probably would have broken all their teeth first. There are two recognized species of Dilophosaurus but may only really be one--D. breedorum is possibly a synonym of D. wetherilli, and "D." sinensis is a separate genus that will be getting a new name one of these days. breedorum is slightly larger than wetherilli, 6.8m vs 6m. Not sure how big D. sinensis is. I'll see what I can do about the dilo chart. And there's already a pretty nice Smilodon scale diagram in the article, so mine would be a little redundant :) Dinoguy2 (talk) 22:23, 5 April 2008 (UTC)[reply]
Oh, ok. I think you're a bit confused about the knee thing. All vertebrate knees, birds human,s etc., bend the same way. The reason people think bird knees bend the opposite way is that people confuse the ankle for the knee. Remember, birds and many dinosaurs (most animals in fact) walk on their toes, not on their entire foot. The forward-bending 'lower leg' of a bird is actually the bridge of the foot (the metatarsals). In most bird, you can't see the actual knee at all because it's under the feathers and the thigh is very short. Compare this diagram of a human leg[10] with a diagram of a bird leg[11] to see what I mean.
Hey BB< it's certainly possible (I'd say very likely actually) that some dinosaurs had sexual dimorphism in their plumage. However I don't know of any evidence for this in currently-known fossils. The only instance I know of Mesozoic dinosaurs with sexually dimorphic plumage is Confuciusornis, in which one sex has a pair of long 'streamer' feathers on the tail while the other sex lacks them. As far as other dinosaurs go, the only semi-clear cut cases of dimorphism are found in ornithoschians like hadrosaurs, but here it's sometimes unclear whether differences are due to dimorphism or to species or population variation. Dinoguy2 (talk) 23:05, 10 April 2008 (UTC)
Hey BB, feather color, dimorphism, display use, etc. is completely unknown and will probably stay that way for a very, very long time, if not forever for 99.99% of dinosaur species. That means you're guess is as good as mine ;) I haven't gotten round to the Dilo chart yet as I've been busy at work but I should have some time today. Stay tuned! Dinoguy2 (talk) 02:48, 17 April 2008 (UTC)[reply]
Huh, I guess WWD didn't do a very good job of providing a frame of size reference then, it certainly was a very small dinosaur. The dilo skeleton you linked looks about the size of the D. breedorum in my chart. Just eyeballing it, the tibia (for example) is a bit more than half the length of the man's arm (not knowing how tall he is). Same in the chart. The skeleton's arm also looks about the same compared to the human. The thing throwing it off may be the skull--the skeleton's skull in the photo looks too big and is obviously a plaster reconstruction, no real bone there. Dinoguy2 (talk) 17:37, 18 April 2008 (UTC)[reply]
Hey BB! Yes, the largest known dilo is D. breedorum at 6.5m (not 7 as far as I know). This is the specimen depicted in red in my scale chart. If you imagine the vertebrae, neck, tail all straightened out, it will reach 6.5m on the chart.
It's hard to say what's "more closely related" to one thing or another without doing genetic studies, which are so far impossible for any Mesozoic animal. Studies of Triceratops protein famously showed that even Triceratops was more closely related to a turkey than to a croc... but the results probably came from contamination (maybe a bit of some scientist's turkey sandwich got in there? ;) ). Still, in a general sense (in terms of anatomy and phylogenetic position), yes, Deinonychus is closer to modern birds than to ornithischians. As for whether it's a bird or a dinosaur, it depends on what definition you use. My personally preferred definition is actually the first cladistic definition of "bird" ever proposed--a bird is any animal that has feathers. Deinonychus had feathers (and may have even had flying ancestors), therefore it's a bird. It's also 100% dinosaur, just like a chicken or a hummingbird. All birds are dinosaurs, including Deinonychus. Not ll dinosaurs are birds, and some definitions exclude more things from being birds than others. Some definitions say a bird is only the groups alive today (the "crown group" definition). If you follow that, even Archaropteryx or Ichthyornis are not birds at all, but non-avian dinosaurs. I think that's kinda silly myself, and I think using feathers is a pretty good standard for what a bird is. Most scientists still prefer to use Archie as a basis for historical reasons, but there are no officially mandated definitions yet. If what a bird is depends on Archaeopteryx, then whether Deinonychus is a bird or not depends on whether it's more primitive or more advanced than Archie, which is still up for debate. Dinoguy2 (talk) 00:35, 23 April 2008 (UTC)[reply]
Hey BB, yes some theropods are real birds: in fact all real birds are theropods! Sparrows and ducks are theropods just as much as noasaurs or allosaurs are. Again, what a "real bird" is depends on your definition. My preferred definition is that anything with modern feathers (composed of a central quill and a vane of barbs, like an old-fashioned writing pen) is a real bird. That means all of Maniraptora. But many (most in fact) paleontologists right now define a real bird based on what's more advanced than Archaeopteryx. My personal opinion is that, if Archaeopteryx is a real bird, why isn't something that's only very, very slightly less advanced? Most paleontologists think Microraptor, for example, is more primitive than Archie, but it in fact has some features that are more bird-like. So why isn't Microraptor a bird too? In my opinion that kind of arbitrary cutoff for such a well-known group is kind of silly. Not calling things like dromaeosaurs and oviraptors birds is very misleading, and lets people think they were more reptile like or more like the old view of dinosaurs than they really were, when in fact there's no real difference between "real birds" like Archaeopteryx and other maniraptors like Deinonychus.
So to sum it up, yes birds are actually dinosaurs. They're a specific group of dinosaurs just like ceratopsians are a specific group of dinosaurs. For the purposes of classification they're set apart in a different class because they have feathers, but it's important to remember that things like "class" and "order are not related to anything real, they're just book keeping tools. Even though birds get a separate class, they're still reptiles, specifically dinosaurian reptiles. They're also archosaurs, which is a larger group that includes crocs. Dinosaurs, birds, and crocodilians are all archosaurs, but birds are technically a subset of dinosaurs just like alligators are a subset of crocodilians, and still archosaurs.
Hey BB! That's an interesting question. I actually heard about the idea that some herbivorous dinos may have been partial omnivores a number of years ago on the DML, and it makes sense to me. Pretty much everything is discussed in your link, so it's mainly speculation, but according to this [12]: "A specimen of primitive ceratopsian (Psittacosaurus) was found with bone fragments in its stomach region. It has been suggested that perhaps all marginocephalians were omnivorous, and possibly their relatives the heterodontosaurids as well." Heterodontosaurids have long been suggested as omnivores because of their mamma0like differentiated teeth, some sharp and pointy rather than plant-eater like. We now know that heterodontosaurs were members of maginocephalia and ceratopsians and pachys probably evolved from heterodont-like ancestors, so why wouldn't they keep the omnivore thing going? The crushed bone fragments in a psittaco specimen pretty much confirm this. As for the fighting dinosaurs, of course it's impossible to tell who initiated the fight, but you're right to point out that we shouldn't automatically blame the "carnivore"--that's Disney bad guy vs. good guy thinking. Just look at hippos: those herbivores are some of the most aggressive African animals and are responsible for more human deaths than any other.
Here's another discussion of the topic: [13]. It lists a lot of modern herbivores that actually kill and eat other animals, and mentions that the ones that do have generalized teeth--just like most herbivorous dinosaurs. Dinoguy2 (talk) 22:17, 10 May 2008 (UTC)[reply]
Hey BB, about the brain thing: I don't think any studies have been done on raptor brains. I know one study done on the brain of Allosaurus showed that it was more like a modern croc than a modern bird. Raptors were more closely related to birds than Allosaurus was, so I think the best we can say is, their brains were more bird-like than allosaurs, but exactly how bird like, we don't know. Of course, the same could be said for Archaeopteryx or Ichthyornis. Our reference point is modern birds, after all. How modern bird like prehistoric birds were is up for debate. Some people have even suggested that, based on bone growth patterns, enantiornithes were cold blooded! Dinoguy2 (talk) 01:10, 16 May 2008 (UTC)[reply]
All reasonable speculation BB, but there's no way to ever test that hypothesis, without direct evidence of feather impressions. You're making (reasonable) assumptions about the type of prey these animals usually ate and the way they ate. We don't know that Deinonychus or Utahraptor usually ate large prey or that they'd usually stick their heads into carcasses to do so, though they very well may have. Also, some other carnivores that do this don't have naked heads (lions, etc.). This might have something to do with grooming. Birds need to preen their feathers. Modern birds use their beaks to do this, but obviously, they can't use their beak to preen the head and neck. Prehistoric birds with clawed wings and semi-mobile fingers may have been able to get around that problem. Dinoguy2 (talk) 02:03, 26 May 2008 (UTC)[reply]
Yes, I noticed the new weight estimates, I added some of them ;) I'm trying to make sure the dino size article reflects real, published science more than internet speculation. The 15t carch example is from the same paper that estimated the 20t spino. I think they're probably at least a bit too high, but it's our job to reflect current upper estimates in the literature. Some people have doubted the method used to get these figures, but only online, not published, so it doesn't "count." But the fact is, that's what that published source got for the weight. Remember that the range of estimates usually reflect lowest estimated studies and highest. The relaity might be one or the other or somewhere in between. Short of putting a live carch on a scale, that's the best we can do.
I agree you're speculation is reasonable, but so would be anyone's ;) How do we know Deinonychus fed more like vultures than like lions? There's no way to know that one way or the other. They might have fed like lions, or like vultures, or some way unlike any modern animal. There's no way to know, so any speculation is reasonable, but not scientific--it can't be, because science is about things you can test, and that it's possible to prove wrong. We don't have Deinonychus feather impressions from around the head yet, so there's no way to disprove your theory, or anyone else's on this issue. Dinoguy2 (talk) 00:44, 28 May 2008 (UTC)[reply]
Basically, the authors found a correlation between skull length and body mass. They tested their method on dinosaur known from complete skeletons like T. rex, and found that it matched pretty well with the sizes estimated based on different methods, even for very small dinosaurs like Mei. The main criticism is that it doesn't take into account weird skull proportions, as they mainly used standard "carnosaur"-type dinos to calibrate the method. So estimates like 20t for Spinosaurus might be off. However, since Carch is a carnosaur, I don't think the criticism applies, so the 15t estimate is probably fairly close to the mark. Anyway, why do you think they're too heavy? I agree they're a bit big, but I haven't conducted any studies on the matter. Dinosaur weight is a very touchy issue--any estimate should be taken with at least a 5t grain of salt, but there should be a valid reason to doubt it, not just "it's too different from the estimates I've heard of before." ;)
Also, again, you reasoning about feeding is fine, but it's wrong to assume that just because the only living bird that eats large animals behaves a certain way when eating, all extinct birds did too. By that reasoning, all prehistoric carnivorous birds like terror birds would need to have naked heads and beaks and behave like vultures too. There's no reason to think this is true, and even some vultures have feathered heads, IIRC. Dinoguy2 (talk) 11:13, 28 May 2008 (UTC)[reply]
I don't know--I haven't done any studies on this myself so I don't feel comfortable speculating. But I tend to doubt ornithischians were very fast either, for what it's worth. And I also wouldn't count out the possibility that some dinosaurs filled different econiches in different life stages, like pterosaurs seem to have done. Maybe a 10 tonne Carch was mainly a scavenger, or kill-stealer. That doesn't mean smaller, younger Carchs were. Maybe older individuals even had a slower metabolism and were cold blooded/giganothermic and only had to eat once a month. It's all pure speculation, but you shouldn't discount a study just because it doesn't sound right according to your intuition or assumptions about how an animal was. I agree with larger size estimates and slower speed, but not the super-high estimates. I doubt any theropod was over 12t, but some studies show they might have been. But IMHO, probably not. Dinoguy2 (talk) 22:14, 29 May 2008 (UTC)[reply]
Yup, but the news stories misinterpreted that part--they were not bad fliers, they just didn't feed while flying. They fed while walking. They could fly just fine, and would have had to to quickly escape predators. The authors of the paper actually made a blog about it! Here:[14]Dinoguy2 (talk) 10:07, 30 May 2008 (UTC)[reply]
Hi, Bamboozlingbert21. I have a friendly question for you. Why don't you ever sign your posts when you make them? Just type four "tildes" ( ~ ) and the Wikipedia software will sign your name automatically. If you don't want to do that, why not just type "-- posted by Bamboozlingbert21"? Have a good one. -- Writtenonsand (talk) 23:42, 10 May 2008 (UTC)[reply]
I did some research and everything I can find says Gustave is estimated to be 6 meters, not 7. However, according to the article, the largest measured nile croc was 6.45m which is pretty close, so I used that one. Hope that's ok, just don't want to use sizes that aren't verifiable in these charts :) Dinoguy2 (talk) 02:56, 3 June 2008 (UTC)[reply]
Hey BB, usually when they say "retractable claws" they really mean "hyper-extendable", that is, digits that can be flexed upward and held off the ground, like dromaeosaurids. No dinosaurs can actually retract the claws back into the body like a switchblade knife or anything. Dinoguy2 (talk) 00:30, 18 June 2008 (UTC)[reply]
Well, Achillobator is a little closer but still too big. The problem is that the overall proportions of the JP raptors were wrong. They were too short in length for their height because their tails were too short. Height-wise, they may have been similar to a smallish Achillobator (or a not quite fully grown Utahraptor--do they say how old they're supposed to be?). That study that found compies to be 40mph was seriously flawed, according to most comments I've seen from other paleontologists, it was way too simplistic, which the authors should have figured out when their formula gave them 40mph compies. Their equations made it so smaller=faster, with no regard for leg proportions, etc. By that logic, Epidendrosaurus would have been something like 100mph. ;) I don't know enough about bite force to know what a good estimate is, like I said before. Maybe you should ask the Dinosaur Mailing List? According to what looks like a good study to me, the force was between 6,400 to 13,400 newtons (force is measured in newtons, not tons or tonnes, which measure weight). Converting that to tons, that would be 64,000kg-134,000kg. Converting THAT to tons, that would be approximately 6.4t-13.4t. Nowhere near 22,000t ;) Dilophosaurids are usually considered coelophysoids, but they may be outside that group, in between coelophysoids and tetanurans, due to the inclusion of Cryolophosaurus, etc. They're definitely not carnosaurs (=allosauroids). Dinoguy2 (talk) 12:07, 20 June 2008 (UTC)[reply]
Hey BB< unfortunately it's not possible to figure out speed just by looking at the length of the leg in comparison with a human. You need to take things like femur/tibia/metatarsal length ratio into account, relative weight (Achillobator may have had human-length legs but what about the rest of its body weight?), variations in musculature and how the muscles attached, range of motion of the leg, etc. Some pretty complicated maths are involved! Musculature is often overlooked--for example, Achillobator has human length legs, but so do I, yet I can't run anywhere near "human sprinter" speeds. Why is that? Relative musculature. My legs are nowhere near as buff relative to leg length as a sprinter. How do you know Achillobator's were? Dinoguy2 (talk) 23:36, 16 July 2008 (UTC)[reply]
Hey BB! I don't know of any croc or monitor brain scan studies off hand, but I'm not really up on the non-paleo literature. I'd try a search using Google Scholar and see what you can turn up. It's hard to measure 'smarts' in any animal, let alone extinct ones, but it seems like large theropods may have been a little smarter. It's hard to compare animals that occupy such different ecological niches. Also I think it's wrong to describe what crocs do (or birds for that matter) as "pack" hunting, since a pack implies a mammalian-style social structure crocs and birds lack. More lick flock or mob coordination. Dinoguy2 (talk) 00:19, 17 August 2008 (UTC)[reply]
Hey BB! Sorry I missed the size graph request, I'll see if I can do one in the next few days. I'm not sure where that 14m estimate comes from, the source is DinoData but they don't provide a reference. I'm guessing it's an older source and probably not correct. I don't know enough about how the different Carch estimates were arrived at but as a general rule, I think the 'average' of two extremes is probably closer to the truth. Dinoguy2 (talk) 01:06, 26 September 2008 (UTC)[reply]
I think 13-13.5m is a reasonable estimate for the largest specimen of Giganotosaurus. Anything else would really be pushing it based only on a piece of lower jawbone! Dinoguy2 (talk) 16:55, 26 September 2008 (UTC)[reply]
Hi there. In case you didn't know, when you add content to talk pages and Wikipedia pages that have open discussion, you should sign your posts by typing four tildes ( ~~~~ ) at the end of your comment. If you can't type the tilde character, you should click on the signature button located above the edit window. This will automatically insert a signature with your name and the time you posted the comment. This information is useful because other editors will be able to tell who said what, and when. Thank you! --SineBot (talk) 17:31, 26 September 2008 (UTC)[reply]
Hey BB, size charts are still pending--just got back from holidays overseas and I'm pretty swamped at work. Maybe this weekend!
Carnotaurus is known from two formations--La Colonia Formation and Marilia Formation. As far as I can find, there are no other dinosaurs known from either. Weird. It was late Maastrchtian, maybe this was the last of the dinosaurs in South America or something. Not sure what the heck it was eating, must have been some straggler species of sauropod around (likely either a rebbachisaur or titanosaur, given what was there earlier). Dinoguy2 (talk) 05:52, 15 October 2008 (UTC)[reply]
Not sure how their jaws could have been used, but clearly they were doing something with them a bit different from other theropods, needing a bulldog shape and all. Carnotaurus couldn't have been preying on Saltasaurus, which lived a few million years earlier alongside Noasaurus. But maybe some kind of saltasaur descendant yet to be discovered lived alongside Carnotaurus. Dinoguy2 (talk) 22:30, 15 October 2008 (UTC)[reply]
Hey BB! I'm on holidays now so I'll finally have some time to work on your chart soon. Skorpiovenator is pretty cool, nice to have some more really complete abelisaurs turning up! They seem to preserve pretty well, between this one, Carnotaurus, and Majungasaurus! Not sure why there are such differences in the Carnotaurus estimates, but the type specimen is estimated at 8.1 meters by Mickey Mortimer, who's usually pretty reliable. There are only two specimens known, one was discovered this year and isn't in the Theropod Database yet, don't know how big it was. Dinoguy2 (talk) 17:07, 13 December 2008 (UTC)[reply]
Hi BB< welcome back! Actually I didn't know about that dinosaur trail, nor that they used my scale charts, that's pretty cool! Wish I'd known about that when I drove through Montana a few years back. I've been pretty busy lately but I've got your predators scale chart on my to-do list, so I'll keep you posted. MMartyniuk (talk) 00:27, 29 September 2010 (UTC)[reply]
. The Tyrannosaurus measured 13 m, to match the uppermost size estimates. Dinoguy2 01:17, 3 September 2007 (UTC)
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![[5]](http://personal.kyoht.com/Tutorial/Raptor/deinonarch.gif){kind=link}
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