Over on AAB I have been debating the relative sizes of the giant theropods Tyrannosaurus and Giganotosaurus with sauropod expert Mike Taylor. Those regular readers of this blog will know I have a longstanding interest in dinosaur body sizes and mass estimates and they are a question that comes up again and again when then the public or media get to grill palaeontologists, if only as framed as “which was the biggest?”.
These are however a very interesting pair of taxa and illustrate a few concepts quite well (namely different concepts of being the ‘biggest’) and are often foremost in people’s minds when they think of giant dinosaurian predators. Tyrannosaurus is famous for its size and is probably one of the most recognisable dinosaurs going, and there is little doubt it was huge – around 12 m in length and something like 8t in mass. For a very long time it was regarded as the largest terrestrial predator and the absence of any detailed information about Spinosaurus (rapidly followed by the absence of any material following World War II) meant that until recently, Tyrannosaurus was pretty much unchallenged. Then a flurry of discoveries in South America threatened the crown of the king severely, most notably through Giganotosaurus, a real giant and almost certainly taking the crown for the longest theropod known at a round 14 m, though Tyrannosaurus was quite probably heavier.
This gives me the opportunity to wheel out this image that I produced for a grant application I made of giant predators that gives you an idea of just how big some of these got. At the front you have a Siberian tiger (white – the largest living terrestrial predator) and Andrewsarchus (grey – the largest known mammalian predator, though its status as a carnivore has been questioned) and then across the back Spinosaurus (white – actually drawn too large, it has recently been scaled back a bit from this and the biggest carnosaur), Giganotosaurus (black – the biggest allosauroid), Tyrannosaurus (grey – the biggest tyrannosaur) and Carnotaurus (white – the biggest known abelisaur). As you can see Tyrannosaurus is massive by any measure, but what interests me is the actual build of the animals and most notably the respective skulls of our featured animals.
This post was inspired by the fact that I ended up discussing (i.e. arguing) about them with Mike the day after I spotted this image online via my colleague Canadian palaeontologist and Tyrannosaurus specialist Eric Snively who kindly passed it on. It is made from CT scans of sculpture reconstructions, of Sue (the famously complete and very large Tyrannosaurus, by Brian Cooley) and the type of Giganotosaurus (by Maria Gravino). It’s taking a team from five countries to turn these into finite element models for bite force comparison research I am I very grateful for being allowed to use it.
- Tyrannosaurus vs Giganotosaurus
The scale may not be exactly right, but it is good enough and it really demonstrates the point I want to make. Tyrannosaurs might not be the longest, or even the heaviest theropod, and certainly it *is* the most over exposed and overstudied, BUT it is also has an absolutely huge skull for its size. Not only is the skull pretty much the same in overall dimensions as that coming from an animal supposedly much larger than itself, but that cranium is far far more massively built. The skull is incredibly robust and well built in comparion to that of Giganotosaurus. It really gives you a feel of just how different and specialised Tyrannosaurs seems to be, since Giganotosaurus really does have a pretty ‘typical’ theropod skull, if a very big one.
Dave Hone's Archosaur Musings 
Just reading all the Ask a Biologist posts.
I love the way you guys can argue and yet keep it nice. A few of the palaeo sorts I know can’t keep it civil for long (especially when arguing about T-Rex ;p ). Its nice to see friendly debates over this stuff.
Also as a frequent user of AAB thanks to you guys for running it!
giganotosaurus may be ‘banana brained’ but it was bigger than the t-rex
Thanks for the comments. We do try to specifically keep it as friendly as possible and it helps that AAB is a relatively small core of people and thus most of us know each other (if only through working on the site). Still, it does get really pretty heated at times and some threads (notably the zebra one I highlighted recently) can runa dn run. I actually think that’s an incredibly important part of the site as it shows people that we are not just dogamtic and on soem issues at least there are disagreements, contradictory evidence and even, yes, mistakes. I have genuinely learned alot from the site myself which is a pleasent surprise.
So…WHY is T rex so heavily built in the skull compared to the big G and other theropods? It would imply to me that it needed the extra bite force…but why? Ceratopsian issues?
I figured it would of had such a massive skull because of its robust prey or maybe it was a sexual feature.
Robust prey partly explains it. There were important differences between LK North American prey and that of the Morrison or K of Gondwana. It wasn’t just the ankylosaurs and ceratopsids. Hadrosaurs almost certainly fled, so it wouldn’t have been effective to run into them with jaws agape. The tyrannosaur wouldn’t have been fast enough relative to the receding prey to hit with much if any power.
I suggest you both read my comment below about the skull shape which rather answers youer question. And see things like Rayfield’s work on skull strength and mechanics and Jacobsen’s work on tyrannosasur bite marks, not to mention my own on prey choice.
It would seem to be a function of feeding / biting. Work suggests that allosaurs (and Giganotosaurus is in many ways a giant allosaur) had a relatively weak bite and relied on the impact of the momentum of the animal to deliver power to a bite (i.e. hitting the prey with the mouth open) wheras the derived tyrannosaurs quite simply had power delived from the actual muscles of the head to make the bite strong. This my be the end of it – it’s merely a difference in style than any special requirement of the tyrannosaurs (cheetahs, lions and hyenas all hunt the same prey types just in different ways). I rather susepct that there are other factors at play as well, but since the grant got rejected, I can’t tell you 😉
What a coincidence! I’m just posting the last post on my arctometatarsalian week, and compared briefly the tyrannosaurid pes with the allosauroid one…
Don’t forget Deltadromeus, (probably) the biggest known ceratosaur! The holotype is a subadult, but based on the referred specimen cited by Sereno et al (1996), its adult femur was 1.2 m long…
*And* as it happens I have just been taking photos of a nice tyrannosaurian arctometatarsal that I want to post on! As for Deltadromeus, i left it out of the image (which is 2 or 3 years old now) becuase at the time it was still listed as a basal tetanuran, and I’m still not sure how certain people are that it is a ceratosaur.
What arguments are being made for Andrewsarchus not being a carnivore? Are people suggesting that it was vegetarian? Or are they just saying it was an obligate scavenger?
I really like that size comparison image, Dave. What’s this I hear about Spinosaurus being scaled back? Is this more recent than the Dal Sasso paper regarding the partial snout fragment? Also, you’ve gotta get Gigantoraptor in there, now that it’s the largest known maniraptor!
Dave, I just read somewhere (and sorry I can’t remember and obviously could not afford to bring my mammalian papers to Beijing!) that it was possibly an omnivore, based I belive on molar shape. I really can’t offer much more than that, but it was in a paper I was able to hunt down while in Germany so it’s probably online, you can take a gander at Google Scholar.
As for Spinosaurus, I think it was the Thierren and Hhenderson paper that suggested the Dal Sasso estimate of 17m was perhaps a touch too big. Sorry about the half answers but I am absolutely swamped right now – two grant applications to get out this week and a couple of appers are well overdue…
You say that the Siberian tiger is the largest living terrestrial predator, I thought that title was taken by the polar and/or Kodiak bear?
What is the citation for Thierren and Henderson’s paper? Thanks…
Masloski – I didn’t include them becuase they are not terrestrail hunters – the kodiak is typcially considered an omnivore and the polar bear gets most of it’s food from the seas which includes hunting in open waters. The focus of the grant which thay image comes from was terrestrial macropredators and large body sizes and thus neither of those two bears really counts.
Steven – the reference is available here: http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1671%2F0272-4634(2007)27%5B108%3AMTIBTY%5D2.0.CO%3B2
Perhaps the term terrestrial carnivore would have been better over the term terrestrial predator. Kodiak bears are terrestrial predators (they prey on other animals) but not terrestrial carnivores (since they’re actually omnivores). Just a thought.
G-carolini is king! FOREVER! HE ALWAYS WIN TYRANNOSAURUS! HA-HA-HA! GIGANOTOSAURUS THE KING OF DINOSAURS!
giganotosaurus is the best,samer as carcharodontosaurus, these have the tittle of the greatest carnivoures dinosaurus
sorry 4 my bad english
You know, I’ve been wondering…if Giganotosaurus ate titanosaurs and rebbachisaurs, then why shouldn’t it have stronger jaws than T-rex; it’s almost like T-rex wants to make a quick kill when it’s dealing with prey smaller than itself, or else, that is comparable to it, whereas giganoto was taking on creatures that were obviously much bigger (although it would obviously have preferred juveniles sometimes). Also, don’t forget Alamosaurus…
I’m furthermore curious about what shuangmiaosaurus the Asian iguanodont looked like? Was it like an Iguanodon, or else like a Camptosaurus or Tenontosaurus?
Well that rather assumes that they were hunting large adult animals as opposed to juveniles (as i have rather strongly suggested on these pages recently) which eleminates much of the size discrepancy.It also depends on what those jaws are doing. Lion shave less robust jaws than hyenas but can kill and eat elephants which hyena do not. Size and power of jaws do not equal size of prey.
As for the igunaodontids, sorry but really not my area. I can tell you though that they are very conservative – that is one igunaodontid looks very much like another and differences can be pretty limited.
I’d further like to know when Zhuchengosaurus lived (during what stage)
It lived in the Middle and Late Cretaceous epochs, more specifically the Albian to Cenomanian stages.
Reference: DinoData – Zhuchengosaurus maximus
No, Zhuchengosaurus most likely lived around the start of the Maastrichtian, although some Zhucheng dinosaurs, including Z. maximus, hint at a terminal Maastrichtian age.
Same basic strategy as hyenas when hunting–though their jaw strength is incredible (so far as I know it’s mainly for bone utilization), when attacking large prey (like water buffalo/wildebeest) they don’t hold onto them the way lions do, but rather bite the target enough to bleed it to death (one video in particular shows a hyena grabbing hold of a wildebeest’s intestine and running away with it).
When something’s that much larger than you, it’s much easier to just let it bleed until it expires instead of latching on and shaking.
Hell, with hyenas expiration isn’t even really required. They’ll frequently eat their prey alive if they know they can get away with it.
I’m not an expert, but basing myself on logic, if you are larger then your intended prey you’d rather hit, crush his spinal bone and kill it with a single powerfull bite.
If you are barley faster then your prey you need to close from an unexpected location like a tree spot, and hit as fast as you can, because your body mass can tire you down fast when you are getting after something that can keep distance from you in a run.
So, ambush, evaluate distance (binocular wiev) dash at the right time (big brain), kill with a powerfull bite.
In the southern emisphere, when chasing a large slow terapod you need help. You need to tire him down, bleding it down and take your time for the kill, because he is much stronger then you.
Once the prey is dead there will be food enought for the whole pack. You probably couldn’t kill him with a single powerfull bite because his bones would be too strong even for a tarbosaurus bite, so you need to bite and slice off letting the bleed do the hard work. A pack of Giganotosaurs (or Carcharondontosaurs) hitting a lone Titanosaur would probably perform like a pack of Raptor hitting a lone Mayasaur in north america.
Furtermore, powerfull maws like those of a T-Rex could be dangerous for you, assuming you can’t overpower the beast you are fighting: immagine a bulldog with the jaws colosed on a large beast like a bull being shaked around, but the Buldog just weight 30kg: now thry to immagine a T-Rex in the same situation… I’d bet his neck would snap under the sheer weight of his body.
So, in conclusion, Alosauroids were the best conceivable shape to kill large terapods, while the Tiranosaurids excelled in killing moderately large bipedal Anatosaurs or whatever else they hunted
I think that any large prey is potentially dangerous to any predator, whether alone or in groups. If you read my work on theropod hunting behaviour you will see that almost no living animals (of any kinds) preferentially hunt adult prey – the almost all prefer juveniles for a variety of reasons, but a prime one being a reduced risk of injury. In the wild, any serious injury (and even some minor ones) can be fatal and as a predator you risk that every time you go hunting, so you need to minimise that risk, and avoiding adults (whether they have armour, or spikes, or horns or even nothing but their size) is therefore a very good idea.
I also think you are overestimating the abilites of predators to kill animals quickly. If you look at the bite record we have for T-rex, it’s powerful yes, but able to kill in one bite? Almost certainly not, unless the prey was much smaller than itself. Cats can kill mice in one go, but they struggle with rabbits for example, and here we are mostly dealing with animals multiple times bigger than the proposed predator.
There is (sadly) no good evidence (or at least none that is especially convincing) for pack hunting in any theropods (as yet) but there is more to come. Certianly our knowledge of allosaurs is much lower than that of tyrannosaurs, but do remember that a) many titanosaurs had armour and b) those sauropods that did not were often very big indeed and both types probably lived in herds. In either case, they would be a challenge for even packs of allosauroids and thus not a tempting target when hundreds of unwary and less protected juveniles were available.
You are right about the danger of killing large anomala, and I bet as well that weak an juvenile target erre always preferred.
My assumption was about the fact that a tyrannosaur hunting, say, a mayasaur, would probably go for the neck, because it could easilly decapitate his prey with a single byte.
Obviously this was bot necessary because a single byte of thecsize and the strenght of a t-rex wasvoften potentially lethal.
The reason of this is that t-rex prey were no big enough to survive, and te size of their bones,enough robot be crushed.
This is not the scenary which a typical allosaurid would face, and I dee a reason in the fact the Carcharodontosaurs survived wherevte prey were large, and exticted elsewhere.
Allosaurs dominated the Jurassic but exticted in the cretacean in North America, replaced by Daspletosaurs and later T-rex.
In Africa and in the South America Were their prey were more similar to’ the Jurassic ones.
Evolution talea ages, but mostly makes sense.
For this reason raptors were bigger in the south.
All this assuming the T-rex was indeed a predator target then an occasionali killer.
But if you accept that these predators would preferentially target juveniles then the rest becomes largely irrelevant since in either case the predator (allosaur or tyrannosaur) would be much bigger than their prospective prey. So all the variation comes down to (or could anyway) different ways of tacking the prey rather than the different prey itself. We have hyena, hunting dogs, cheetah, lions and leopards all co-exisiting and hunting similar or the same species in Africa. Just being different can reflect different strategies. Asiatic lions are very similar to their African cousins yet do not (and cannot) hunt wildebeest and zebra in open plains. In short prey can vary, but that need not vary the hunting mechanism and associated morphology.
(sorry for bad english: i’m on a cellular phone and spelling corrector messed all up >__>)
No problem, don’t worry!
To further elaborate, we could assume the giganotosaur albeit huge, fighting as a fencer, with optimal all around situation awarness to ward off from side attack (whip tails, other animals, ecc), and the Tyrannosaur fighting as a bruiser, to fast overpower the prey, dashing out at the right moment, with optimal stereoscopical vision. The large olfactive lobes Aldo male dense of you act as a scavengers too.)we could immagine the T-Rex as a Tiger and the allosaurs as wolved.
Another reason for the dofference in the jaw aspect between the carcharodontosaurids and the tyrannosaurids may be the way they feeded.
Let’sagine the T-rex acting like a sort of big hyena, which consume his prey entirely bones included to’ sustain his large body with relatively small preys, and countin on his size and streght to’ jeep other scavengers at bay while it ate. As for the allosaurids, assuming they hunted in packs (which is likely, given the size and strength of their preys, they could have hunted, killer, ate, without need to consume the whole prey (which was oversized) and this did not required such powerfull jaws to crush the bones (which were oversized too).
I think you are over extrapolating here. We really don’t know that much about how these animals hunted or fed, or how prey species could defend themselves. To my knowledge there is no direct evidence of any carcharodontosaurids feeding on large sauropods (I expect there are some bite marks somewhere that are unreportrd, but I’m not aware of any) let alone healed bite traces that indicate active predation attempts. As such, whole I am sure these were occasionally attacked, to try and work out entire evolutionary patterns of hunting behaviour based on the assumption that species X hunted species Y in manner Z is rather pointless at the moment since there is just no good evidence to support any part of it, and as I note above there is a lot of variation and overlap seen in which animals hunt which others and how.
True !! pack hunting also suggests they may have had high levels of intelligence ! ( although their brain wasnt as big as TRex)
You are right and I got a little caried away here.
There is no solid proof of the Carcharondontosaurs feeding on large sauropods, and even what little we know of their cousins, the Jurassic Allosaurs, is based on the assumption they actually preyed on adult apatosaurs instead of just occasionally feeding on carrions. Still we have proof of Allosaurs teeth on adult Apatosaur bones, as well as Tyrannosaur teeth on Triceratops… But if we relate the behaviour of Giganotosaurs to that of ancient Allosaurs we MUST take in account how many Alosaurs skeleton sohow sign ofdamages and hard fighting, menaning this was a very agressive specie
May we assume the T-Rex actively feeded on adult triceratops because of teeth sign on Triceratops skeletons?
I doubt that except in desperate cases because of the danger they would have faced.
About the Tyrannosaurs we know little more then this because we know they “could” kill but there are speculations about them being little more then scavenger, bullying other predators with shear size and force, as the large olfactive lobe seems to suggest (find carrions at very long range).
Beware, Im not implyng that Allosaurs were killers ad tyrannosaurs carrion eater. We simply don’t know.
But keeping on speculating, why then the Allosaurs desappeared form the north Amercian continent with the extinction of the large Sauropods, but we still find them prosperating in Africa and South America, where these sauropod were still rather common?
We know they faced active competition from other carnosaurs, like the ceratopsian, and we know the size of these increased in the souther emisphere as much as the Allosaurid did.
But I guess
So we found a clear mark disticntion between the Along the cretacian Tyrannosaurids and the Carcharodontosaurids: the first ones propsered where the climate was less humid and where the Ceratopsids and Adrosaurs prospered, which means north asia, and north america. The seconds propsered where the climate more resembled what it was like in the jurassic era, with large sauropods and a relatively humid climate.
Interestingly, we found the the only cousin of the Allosaurs in NA did not fared so well (given the number of fossiles we found), while in SA we did not found other Tyrannosaurids.
We don’t know if this is related to “phisiology of social behaviour of the two different kinds.
We may speculate the allosaurs were better suited for pack hunt to large animals where the tyrannosaurids were better at ambushing and killing moderatley sized beast alone, or with small family groups? We dont know.
Interestingly the only part of the globe where the Allosaurs were not found side to side to larger plant eaters was in Antartides where may be it was isolated and faced much less cocnocrrence by other predators
I’m sorry but once more I think you are over extrapolating based on a lack of evidence and
“but if we relate the behaviour of Giganotosaurs to that of ancient Allosaurs we MUST take in account how many Alosaurs skeleton show sign of damages and hard fighting, menaning this was a very agressive specie”
– But so do many extant animals too – modern carnivores often break their teeth and are left with minor injuries inflicted by prey and accidents during hunting. As predators get older they become much more susceptible to these kinds of injuries as well. You’d need to show that Allosaurus was especially vulnerable and I don’t see any evidence of this. Certainly there are lots of other theropods showing injuries of similar kinds to those in allosaurus.
“May we assume the T-Rex actively fed on adult triceratops because of teeth sign on Triceratops skeletons?”
– Fed on the bodies, yes. Killed, no. There is no good evidence for them actively killing adult Triceratops – an important distinction.
“why then the Allosaurs desappeared form the north Amercian continent with the extinction of the large Sauropods, but we still find them prosperating in Africa and South America, where these sauropod were still rather common?”
– True, but then the tyrannosaurs were also appearing at this time. Was this change caused by changing flora, changing herbivore populations or changing predator populations. And the sauropods did fine in Asia and the southern part of North America where the allosaurs still died out, so this is hardly a very unambiguous pattern.
“while in SA we did not found other Tyrannosaurids”
– But this could be becuase they never made it that far south rather than this was an unsuitable habitat for them.
“Interestingly the only part of the globe where the Allosaurs were not found side to side to larger plant eaters was in Antartides where may be it was isolated and faced much less cocnocrrence by other predators”
– I assume you mean Antarctica, and here we have so few fossils I think it’s meaningless to make any serious statements about the faunal composition as we really have no idea what it was like there.
You are of course welcome to speculate about how these animals may have lived and acted, but I really think you are overlooking big contradictions to some of your basic assumptions and extrapolating across places where there is very little data to support any ideas.
As you say I “AM” extrapolating since there is very little else to do about very rare animals like the Carcharodonosaurids.
How many skeletons in good SHAPE we have to try an extensive survey of how they lived?
We chose to assume all these predators, like the t-Rex were active hunters rather then carrion eaters, because the mass of their supposed preys, the ammount of food they ate, the age of the adults, suggests just sitting aroud waiting for them to die of age or illness would have been impractical.
Then because of the similiarities between Giganotosaurs and Allosaurs, both in Shape and habitat we have to speculare they filled the same niche.
I’m no expert, i admit, just fascinated by these animals, but i try to speculate on facts of I can: for example, we know the allosaurs in North America was prone to absorb a lot of punishment along their life, usually more them other carnivores of the era, like ribs and leg fractures, much more in facts then the tirannosaurids (another well known and well studied predator) several millions of years later which, to me, means (speculating again) that their environement was more dangerous, possibly because of stronger preys or killing patterns.
I don’t know if this is entirely applyable ro their late cousins, the Carcharontosaurs, larger and heavier, but is a fact that the plans of south America in the cretacean had a lot in common with the Jurassic North America in climate and fauna.
If we assume allosaurs were sauropods preyer, it’s relatively safe to assume the same for their late, southern cousins in the cretacean.
And I’ll go for another pure speculation: what if the hunting abit of the allosaurids tied them strictly to the large sauropods, so that they prospered wherever the large herbivores lived?
I’m trying to parallel the lions in the savana, with the Tiger in the forest: large packs of predators for large and abundant preys (which are often larger then the predators themselves, like zebras and buffalos), vs solitary hunters trying to ambush smaller preys alone overpowering them with size and strenght
“the age of the adults, suggests just sitting aroud waiting for them to die of age or illness would have been impractical.”
– I’m not suggesting this – I’m suggesting they ate the juveniles and largely ignored the adults.
“i try to speculate on facts of I can:”
– That’s fine, but as I note, the facts are largely few and far between, so you can fill in almost any story or concept between the few facts we have and it will fit. As a result, it doesn’t get you very far. You can equally say allosaurs are pack hunters, or lived alone, or predates sauropods mostly or stregosaurs mostly and there is nothing to show either is right or wrong, hence I think the speculation is fun, but meaningless.
“, usually more them other carnivores of the era, like ribs and leg fractures, much more in facts then the tirannosaurids”.
– Where have you got this from? I’m genuinely interested – is there a paper on this? I’ve never seen any work suggesting this as a pattern.
“If we assume allosaurs were sauropods preyer”.
– That is a huge assumption and we do have evidence of allosaurs at least feeding on stegosaurs, and probably killing them too.
“what if the hunting abit of the allosaurids tied them strictly to the large sauropods, so that they prospered wherever the large herbivores lived?”.
– But as I noted, this can’t be the only factors since the allosaurs and their kin do not do well in Asia in the Late Cretaceous of Asia where there are still sauropods and in southern North America too.
“lions in the savana, with the Tiger in the forest”.
Well yes, but there are also lions in the forests in India and in Africa in places. And then there are leopard, hunting dogs, hyena, dhole, cheetah and more. You can’t ignore the other predators either in one system (modern times) or the other (dinosaurs). And here the parallel shows the opposite I think – tow very closely related sister species that have very different hunting patterns, showing just how much variation you can have even within Panthera, when you are trying to compare different families but maintaining consistnecy within those clades.
Not that I would not expect tyrannopsaurs to be generally similar and allosaurs to be generally simil\r, but this example does not serve your ideas well.
I’ll try to find the charts about Allosaurs phisical damages.
but I’ll not able to do that untill monday I think
Sorry for the delay.
I checked the charts but I can’t find nothing conclusive about the damages and fractures on allosaur skeletons.
The only reference I found (and probably what trigged my memory) is about an old history channel program showing a recostruciton of what may have happened in a bollodbath near a water poll (three allosaurs and a ceratosaur probably killed in a fight with a two styracosaur and a camerasaur get bogged down in themud. Here a paleontologist tells that many allosaur skeletons show sign of stress and damage.
Not the best of the sources but still someting.
I cant confirm nor negate the autenticity of what the Palontologyst says.
Well yes that’s hardly convincing evidence that allosaurs were at more risk of injusry than other theropods. Even if the situation you describe didi happen it could still be considered and exceptional event rather than a normal predatory situation and thus again not exactyl convincing.
To be honest, I grew up a Dinosaur enthusiast, and yes, Tyrannosaurus Rex had my love from the start. However as I grew older, I’ve grown a big interest into these prehistoric predators, and although I’m no “paleontologist” per say, I do feel that I would know more then the average person who simply goes “Wow, a Dinosaur!”.
In my eyes, and from what I’ve read, seen, at least have had some small experience of learning first hand. Tyrannosaurus Rex is in my mind, the most powerfully built predator of all time, more so then even Giganotosaurus and yes, even Spinosaurus whom is regarded as being the largest giant theropod dinosaur to date.
Just by looking at the anatomy of T-Rex in contrast to all other giant theropod dinosaurs, the body frame is just so robust and heavily built. The neck is far more stocky in contrast to other large theropods, the skull is more broad and wide, the teeth are absolutely unbelievable.
I’ve bought a real life die cast of a Giganotsaurus and Tyrannosaurus Rex tooth. Both are amazing and large, however the T-Rex one dwarfs the Giganotosaurus by some degree. Obviously they were used in different behavioral hunting forms, however the Rexes tooth is just enormous in contrast.
Another thing that really seems to fly away from generalist is the vision of T-Rex. I simply cannot stress this enough, eye-vision is so important if you are a land predator, and especially one who is supposed to be at the top of the food-chain. Binocular Vision is something that T-Rex has in leaps and bounds over it’s other large contemporary contenders like Giganotosaurus and Spinosaurus.
When you can accurately pin-point your prey or “opponent” it makes life alot easier. I don’t see how an animal such as Giganotosaurus or Spinosaurus can do the same without resorting to swaying their heads from left to right, due to the fact their eyes are pointed to the sides.
I’ve never believe in the ‘pure’ scavenger theory as well, and I’m glad that Horner seems to be switching and changing his view points in this, because any large theropod to me would have scavenged if given the opportunity due to their sheer size and intimidation factor.
So yes, I’m pretty sure I’m already posting things that you clearly know, however to, I strongly feel that with all of the evidence we have thus far, T-Rex is still the undisputed unrivaled giant theropod dinosaur to date. Although some giant theoropods are named to be larger than Tyrannosaurus Rex, it is still the most advanced, and most powerful lb for lb giant theropod we know of today.
Simply put, if you had a “Coliseum” type battle between all of these giant theropod dinosaurs, I would bet 9 out of 10 times T-Rex would emerge victorious.
As a long time amateur paleantologist, I agree with you, with the reservation that it would depend on who got a clean bite on the other one. The probable reason the ‘gig’ is heavier is because it had longer arms, and needed a longer tail to compensate for its added frontal weight. The disadvantage to this is that it will weigh more, thus, make it slower to react, all other things being equal. If T. rex got a hold on ‘gig’s’ neck, it would be all over, due to the enormous muscles in Rex’s neck and jaws. Furthermore, having bi-focal vision is really an advantage in fighting, judging distance being crucial. T Rex had a larger brain, and was just a more advanced predator.
why doese it mater who wins its just a comparison so what everyone knows its the t-rex he was the king of his time not many creatures can kill him, so its kinnda obviouse he is going to win
If it doesn’t matter then you wouldn’t need to reply now would it? However, it’s just interesting and fun to speculate about such things involving these magnificent creatures.
During his time, he obviously would have been King, considering no other giant theropod predator we know today was remotely close to rival Rex in size during it’s reign.
A magnificent animal, and easily the most powerful land predator we have discovered to date.
I know this is kind of off topic, but weren’t healed tyrannosaur bites found on edmontosaur bones? Also, weren’t there easier prey items for the giganotosaurs such as ornithopods? Also, I’m not sure why it would be more likely for allosaurs to sustain injury than tyrannosaurs when tyrannosaurs had such potentially lethal prey to deal with. Ankylosaurs, Triceratops, Torosaurus…. Even the Anatotitan were comparable in size to tyrannosaurus… Couldn’t a fatal injury be sustained from comparatively weak prey such as this? I imagine that advanced predators in general hunt the young, sick, injured, or old. I mean, as lethal as those jaws likely were, a healthy adult Triceratops would present too much of a risk. Especially considering that at 12 tons the prey in question might be twice the predator’s weight. As much as we would love to imagine a multiple round battle to the death between these animals I’m sure it didn’t happen that way. Perhaps tyrannosaurus would surprise its prey and wait for the prey to succumb to the massive trauma inflicted by its jaws. Remember how advanced tyrannosaurus’ sense of smell was supposed to be… Perhaps it could track its victim for miles.
I don’t think there’s much of a discussion going on here still Justin, the comments have rather dried up. Still, I suggest you read this, and ideally, the paper that goes with it. I have quite a lot to say on theropod predatory behaviour….
Sure Justin, healed T. rex bite marks have been found on Edmontosaurus and Triceratops (=Torosaurus?). Even ankylosaurs show evidence of coming under attack. I don’t doubt that a large theropod would gladly devour juvenile prey. But I don’t think juveniles were their principal food. For one thing, LK environments had a great diversity of small theropods. Dromies, troodonts, oviratorids etc more likely filled the nest raider/”baby killer” niches. Also, why was enormous size and brute power, in T. rex particularly, selected for if the prey was mostly little shrimps? Lastly, dinosaurs probably protected their young. Even primitive archosaurs like crocodiles wil respond to a baby’s distress cry. If a large theropd couldn’t take on mommy, he may not have been able to get juveniles often. If he could take on mommy, juveniles would’ve been superfluous.
I disagree with quite a lot of those assertions, or at least their magnitude. However, I don’t want to delve into it here as I covered most if not all of it in the paper. I suggest you give it a read.
“…carcharodontosaurs picking on the great hadrosaurs…” LOL!
It’s possible that in most cases, large theropods stripped flesh from bone without biting into it–unless it was small/thin–which might cause tooth loss. Sure, dinosaurs had high reproductive rates. But it seems that so many small theropods could’ve nailed the young before they were large enough to be suitable prey for large theropods. In fact, oviraptorids may have eliminated a large percentage of nests before the infants could emerge. As soon as they did, IMO, ornithomimids, troodonts etc made short work of most of them. The vast bulk of crocodile hatchlings don’t live a year. Certainly predation kept juvenile numbers down in dino communities as well as extant ones. But given the abundance of probable nest raiders, I doubt the large theropods played much of a role.
I do suspect that abelisaurids were mainly hunters of juvenile sauropods. But while T. rex faced potentially dangerous prey, there were plenty of hadrosaurs which weren’t so dangerous as adults.
Yeah again, you really need to read the paper. But the very least you are extrapolating off minimal / no data here. I don’tdoubt that small theropods did take some small dinosaurs, but they also had access to all kinds of other small prey – mammals, lizards, snakes and other small reptiles, small pterosaurs perhaps, various insects and arthropods etc. that large theropods did not. And don’t forget a ‘small’ juvenile hadrosaur could still be several hundred kilos – too big for a maniraptoran. Don’t get fixed on ‘baby’ think about ‘juvenile’ which covers a much greater size range.
I tend to doubt small nonavian theropods relied largely on little mammals, reptiles and insects etc. Most mammals are thought to have been nocturnal, whereas dinos were diurnal. Aves probably ate insects and other small nondinosaurian prey. That’s probably why neornithines survived the K-T while small theropods didn’t. The latter were too dependent on other dinosaurs, which vanished. Oviraptorids are thought to have been specialized egg plunderers. Ornithomimids–considered carnivorous by Osmolska and Barsbold–probably dashed to nests and bolted down hatchlings. Troodont teeth have been found in the Campanian egg mountain hadrosaur nests. The teeth and claws of dromies point to small dinosaurian prey, including juveniles too large to have been eaten by ornithomimids. Consider also the possibility that small tyrannosaurids like Alioramus are valid. The nest raider niches were very lucrative and dinosaurs tended to be specialized. True, juveniles soon grew much bigger than babies. But most babies probably never lived to see their first birthday. The vast bulk of croc babies are cleaned out after just 6 months.
As I suggested before, abelisaurs may have been primarily baby sauropod killers because they don’t look big enough to take on adults, and little other suitable prey was available in some of their environments. If a large theropod focused on juveniles, there would be no “arms race.” That might explain why abelisaurs never grew as big as say, Mapusaurus even though they lived with some big sauropods. But elsewhere, “arms races” suggest that encounters tended to involve adults, in which size and armaments were fully expressed, necessitating a response by one party or the other.
Ok, *really* read the paper, and some modern literature.
Well things like Coelophysis, Compsoganthus,and other small manirpatorans have evidence of eating small prey, including lizards. So this was happening. Evidence for consuming juvenile dinosaurs is all but non-existent in these smaller species, whereas there is extensive evidence for large theropod eating juvenile dinosaurs. So all the available evidence points to my hypothesis and not yours. You might want to read my paper on this. Like i suggested several days ago.
“Oviraptorids are thought to have been specialized egg plunderers. ”
Not true. Most people consider them omnivores or herbivores.
“Ornithomimids–considered carnivorous by Osmolska and Barsbold–probably dashed to nests and bolted down hatchlings.”
Also widely considered herbivores.
“Troodont teeth have been found in the Campanian egg mountain hadrosaur nests. ”
Troodontid teeth are found everywhere. All this says is that some may have eaten eggs / hatchlings which is not much of an issue, I bet they did, but did they only eat them? No. There’s also evidence fro troodontids scavenging azdarchid pterosaurs, but that’s not their only diet either.
“The teeth and claws of dromies point to small dinosaurian p
prey, including juveniles too large to have been eaten by ornithomimids. ”
Where’s the evidence for this? Small prey yes, small dinosaurs? Who knows.
“The nest raider niches were very lucrative”
Prove that these were filled by specialists.
“and dinosaurs tended to be specialized.”
Where’s the evidence? This is just unsupported hypothesising.
“True, juveniles soon grew much bigger than babies. But most babies probably never lived to see their first birthday. The vast bulk of croc babies are cleaned out after just 6 months.”
Yes, I know. And I write about this extensively in the paper that you have clearly still not read.
“If a large theropod focused on juveniles, there would be no “arms race.” ”
Based on what? There are lots of other factors at play. I’m not saying they *only* ate juveniles, just primarily. And in any case that still leaves inter and intraspecific competition, changing environments, and the variety of prey species out there. Not every taxon gets into a red queen situation.
Read the papers and look at the evidence. I think you’ll see that a lot of what you are suggesting is not supported by the evidence, or is ambiguous. Just stating things does not make them true and you have missed an awful lot of information.
Total specialists are a rare thing in nature, they tend to wind up in symbiotic or parasitic roles.
Humans compulsively letterbox things to make it all a bit simpler, nature constantly competes and improvises, absolute specialisation is a vulnerable place to be.
Well they do turn up of course – just look at anteaters sat, but then you can usually tell that they are specialised as they have a very specialised morphology with generally lots of unusual functional characters going on. It’s still not certain what the derived alvarezsaurs are doing for example, and look at the levels of adaptations there throughout the skeleton. You just don’t see things like that in my theropods.
Some changes sure (reduced arms in tyrannosaurs and ceratosaurs, large tooth serrations in troodontids, raptorial claws in troodontids and dromaeosaurs, twisted carinae in dromaeosaurs and tyrannosaurs etc.) but a whole suite of highly derived characters all focused at one thing? Not really. Not on the scale of something like an alvarezsaur or pangolin and even these are less specialsied than one might imagine. Aardvarks will apparently eat small mammals and birds eggs for example.
Phil Currie noted evidence that Oviraptor was adapted for egg predation. I recall some dromie baby skulls were found in an oviraptor nest, suggesting the young were fed meat before they could devour eggs. Osmolska and Barsbold wrote that ornithomimid skull structure/kinesis points to carnivory, as in other theropods. Of course, they and troodonts etc could’ve eaten small prey besides dinosaur babies. But the latter were so common it wouldn’t be surprising if small theropods were specialized nest raiders or baby eaters–it would be surprising if they weren’t. As for Triassic/EJ small theropods, it apparently took a long time to occupy the nest predator niches. Even in the LJ or EK, small crocodilians had them. (Note that in LK India, which didn’t have the variety of small theropods observed in Asia/America, a snake species went after the hatchlings.)
Large theropods couldn’t swallow the skeletal elements of big dinosaurs just small ones. They weren’t hyenas who could grind up bone. Nor would they have left many conspicuous tooth marks if they were just stripping meat from bones; biting with much force may only have occurred in combat, and even then they would’ve targeted fleshy areas.
Consider also the possibility that much of the evidence we now have–the coprolites or stomach contents with small or juvenile remains–reflected highly stressful conditions instead of normal-predator/prey interactions. Many dinosaur specimens we have died in droughts. Isn’t it possible that, as a drought wore on, the large prey, with its greater food/water requirements, was the first to die, and the small prey last? So that, the large theropods, prior to their own death, were reduced to eating small/juvenile prey (subsequently fossilized as stomach contents/coprolites)?
For a start at least some oviraptorosaurs were likely herbivorous (e.g. Caudipteryx) and at least part of the supposed adapatations for egg eating were put forwards before it was realised that these things were nesting. I don’t doubt they took small prey on occasion (including juvenile dinosaurs) but that does not make them habitual predators of such things, and some of the supposed adaptations for egg eating appear in non-predator oviraptorosaurs in any case making them questionable.
“Of course, they and troodonts etc could’ve eaten small prey besides dinosaur babies. But the latter were so common it wouldn’t be surprising if small theropods were specialized nest raiders or baby eaters–it would be surprising if they weren’t.“
Again, this is unsupported. You’re assuming there must have been egg / nest specialists and are assuming that these small maniraptorans must have filled this assumed nice. We don’t know just how numerous other small prey was. Crocs, turtles, lizards and snakes abounded then and they all produce large numbers of eggs, and smaller mammals tend to have more offspring (and perhaps pterosaurs and early birds too). Juvenile dinosaurs would have been present in large numbers yes, but so too would everything else. There are dedicated egg-eaters in modern times but they don’t outcompete everything else for eggs / juveniles, they are part of a bigger fauna. Where is the evidence that these were egg / juvenile specialists?
“Large theropods couldn’t swallow the skeletal elements of big dinosaurs just small ones.”
I know. I wrote about this and discussed it’s implications in some detail.
“Consider also the possibility that much of the evidence we now have–the coprolites or stomach contents with small or juvenile remains–reflected highly stressful conditions instead of normal-predator/prey interactions.”
Nonsense. This is true of every metazoan system that has been studied. Even starfish and mantids prefer juvenile prey. This is pretty much an ecological absolute, not evidence for some kind of super-stress environment.
Short version, all small theropods with stomach contents have non-dinosaurian prey in them, all big theropods with stomach contents have juvenile dinosaurs in them (or their coprolites). So, while the evidence is limited, it fully supports my hypothesis and does not support yours. There are plenty of other factors at play too and these are discussed in the paper (and to a degree in the blog post I linked to) but you seem to be all but deliberately avoiding reading it.
I’ve now written a couple of thousand words explaining largely what I have already explained both in my blog post and in the actual paper. Do me the courtesy of reading my work. This means that I will not waste my time having to write this all out again longhand for you like I am currently doing (despite repeated requests) and maybe you will see my point. You are in places trying to suggest I’m ignorant of things that I have explicitly discussed and explained. This is the point of such a paper, to explain and sysnthesise and summarise the data, don’t ignore it.
I’m sure Phil Currie was aware that the Oviraptor found with supposed protoceratopsid eggs was in fact brooding its own before he made a case for oviraptors as adapted to egg eating in THE COMPLETE DINOSAUR. Another study by Headden IIRC also noted that, despite the old error, oviraptors were still likely egg hunters.
LK Mongolia probably has the best record of small/medium theropods. AFAIK snakes were absent. Crocs were rare. Turtles were sometimes plentiful but were aquatic (even Zangerlia is thought to have been) hence probably inaccessible to theropods. Lizards were common but included varanids which probably preyed on the others and mammals, which were probably burrowing and nocturnal. Bottom line: there wasn’t all that much for small theropods to eat besides small/juvenile dinosaurs.
Sorry I don’t know where to find the paper. I’m not sure if we really disagree all that much. My suggestion is that large theropods ate the following:
Hadrosaurs: 40% of individuals eaten were juveniles/subadults, 20% infirm/old adults and 40% healthy adults.
Ceratopsians: 50% juveniles/subadults, 30% infirm/old adults, 20% healthy adults.
Ankylosaurids: 70% juveniles/subadults, 20% infirm/old adults, 10% healthy adults.
Sauropods(LJ, late EK, Cenomanian Gondwana): 40% juveniles/subadults, 30% infirm/old adults, 30% healthy adults.
Sauropods(LK Gondwana): 70% juveniles/subadults, 25% infirm/old adults, 5% healthy adults.
“Crocs were rare. Turtles were sometimes plentiful but were aquatic (even Zangerlia is thought to have been) hence probably inaccessible to theropods. ”
Not where I have been they are not, lots of crocs scutes and turtle plastron, and tons of non-dinosaurian eggs. And in any case, even aquatic turtles lay eggs on land.
This also explains only a single locality, not all places where small dinosaurs lived.
There is also a more profound problem with the idea of very highly specialised egg / juvenile predators. Even modern equatorial animals have breeding seasons and the higher the latitude the more extreme that gets (and we do have goo evidence for seasonality in breeding in various places and dinosaurs were living and probably even breeding at very high latitudes). If these animals were super specialised, what did they feed on for the 6-9 months of the year that there were no hatchlings or eggs?
Juvenile dinosaurs grew very fast and a baby titanosaur would rapidly get too big for a dromaeosaur to handle. What did they eat then? Either they fasted for half a year, or they ate other things which means they *can’t* have been that specialised.
“Sorry I don’t know where to find the paper.”
Well it is online in a couple of places or you could ask me to e-mail you a copy.
“Hadrosaurs: 40% of individuals eaten were juveniles/subadults, 20% infirm/old adults and 40% healthy adults.
Ceratopsians: 50% juveniles/subadults, 30% infirm/old adults, 20% healthy adults.
Ankylosaurids: 70% juveniles/subadults, 20% infirm/old adults, 10% healthy adults.
Sauropods(LJ, late EK, Cenomanian Gondwana): 40% juveniles/subadults, 30% infirm/old adults, 30% healthy adults.
Sauropods(LK Gondwana): 70% juveniles/subadults, 25% infirm/old adults, 5% healthy adults.”
This is just made up! What can this possibly be based on? Do you have any evidence at all that this ever happened? You can’t know this. How exactly do you determine which animals were killed in which proportions by which predators based on the fossil record?
If the place was Bayan Mandahu, no wonder turtles and crocs were numerous, but they were less plentiful in the slightly younger “classic” Djadokhta environments, where oviraptors dromies etc were very numerous. Some time ago in the dinoforum, the issue of seasonality came up, and someone pointed out that it doesn’t prevent some species from becoming specialized egg eaters. I don’t think dromies co occurred with titanosaurs, except in Europe, where there were also the offspring of hadrosaurs. Of course, Asia-American faunas, where small theropod diversity peaked, were even more diverse. If you state the title of the paper I’ll google it. Of course the figures were made up, lol. They’re just “guesstimates” based on the prowess of contemporary predators and defensive abilities of the prey. For example, I suggested hadrosaurs were more likely to be killed as adults than ceratopsids and anylosaurids.
Bayan is considered equivalent in age to the Djadokhta, and share much of the fauna and is simailar in environmetla compostition too. And in any case this supposed difference still only explains a single locality, not all times and places.
“someone pointed out that it doesn’t prevent some species from becoming specialized egg eaters.”
Some occasional species, no, a huge clade of small theropods though? That is another matter entirely. And egg eaters are incredibly rare as specilaists which is what you suggested.
“They’re just “guesstimates” based on the prowess of contemporary predators and defensive abilities of the prey”.
Sorry no, thse are not even guesstimaes. They are all but random. You simply can’t write this stuff, even as a supposed guesstimate and expect me to take it seriously. Even your supposed criteria ignore far mopre important potential factors like population structure, diversity, species density and distribution, migration etc. Since it is therefore meaningless, it rather undercuts anything you might be basing it on, or may have used to get there. Sorry, but I say again, you have to use evidence not some vague assumed notion of how things must have happened.
As for the title of the paper, it’s in the blog post, as well as a great deal of more information on the subject. There’s a link in the comments and elsewhere. Just googling my name and dinosaur should trun it up, or you could use my research page (linked on the side bar).
However, I am frankly pretty bored of all of this. You do seem to have some knowldge but you are not putting it in context and are ignoring swathes of evidence (stomach contents, bite marks, poplation distribution) or putting in huge and incorrect assumptions (egg eaters must have evolved, troodontids were dedicated egg eaters, theropods would only eat juveniles during difficult conditions). It’s fine to talk and discuss things, but I seem to jsut be having to correct your misunderstandings of some fairly basic biology here and it is trying. I really suggest if you are interested you try and read up on this, but this is just me typing out thosands of words to correct stuff tha I really shouldn’t have to and have mostly written out already both in the paper and in the blog. Doing it all again point by point is not really what I want to spend my time doing. Go get the Complete Dinosaur, or the Dinosauria and get reading. You’ll learn much more and it’ll save us both a lot of frustration.
IIRC Bayan Mandahu isn’t exactly equivalent to the classic Djadokhta exposures but slightly predates them and in any event appears representative of a somewhat wetter environment in which small nondinosaurian prey was more numerous. I didn’t say troodonts were dedicated egg eaters or that large theropods would only eat juveniles during difficult conditions. I read The Complete Dinosaur and The Dinosauria (vol. 1) some time ago. Specialized LK nest raiders/juvenile eaters seems reasonable considering that egg laying, producing numerous offspring, was far more widespread in the Mesozoic than in recent mammal dominated environments. But if you don’t want to discuss this further, fine. I’ll see about the paper.:)
“I didn’t say troodonts were dedicated egg eaters ”
You suggested these could happen or were likely reasons. OK, nest-raiders rather than egg eaters, but you did say they would not likely take other prey.
“The nest raider niches were very lucrative and dinosaurs tended to be specialized.”
“Dromies, troodonts, oviratorids etc more likely filled the nest raider/”baby killer” niches.”
“I tend to doubt small nonavian theropods relied largely on little mammals, reptiles and insects etc. Most mammals are thought to have been nocturnal, whereas dinos were diurnal. Aves probably ate insects and other small nondinosaurian prey. That’s probably why neornithines survived the K-T while small theropods didn’t. The latter were too dependent on other dinosaurs, which vanished. ”
“In fact, oviraptorids may have eliminated a large percentage of nests before the infants could emerge. As soon as they did, IMO, ornithomimids, troodonts etc made short work of most of them. ”
“or that large theropods would only eat juveniles during difficult conditions.”
Near enough….
“Isn’t it possible that, as a drought wore on, the large prey, with its greater food/water requirements, was the first to die, and the small prey last? So that, the large theropods, prior to their own death, were reduced to eating small/juvenile prey (subsequently fossilized as stomach contents/coprolites)?”
“Specialized LK nest raiders/juvenile eaters seems reasonable considering that egg laying, producing numerous offspring, was far more widespread in the Mesozoic than in recent mammal dominated environments.”
But again, ther’e snot support for this. You are jsut assuming it must be true and evolution doesn’t work like that.
I’m glad you are reading stuff, and thank for accepting that I don’t want to go down this route. Obviously I go to a lot of trouble to try and communciate science well, I’m interested in it, but you have to try and meet with people when discussing things liek this with an expert. You did start off criticisng my interprestation of my data and my hypothesis without reading my work or the blog post (easy enough found) which does not help. You have then thrust more and more stuff at me without ever laying out what your position actually is or what it’s based on rather than a few rather poor assumptions and criticing my position without knowing wha
“I didn’t say troodonts were dedicated egg eaters ”
You suggested these could happen or were likely reasons. OK, nest-raiders rather than egg eaters, but you did say they would not likely take other prey.
“The nest raider niches were very lucrative and dinosaurs tended to be specialized.”
“Dromies, troodonts, oviratorids etc more likely filled the nest raider/”baby killer” niches.”
“I tend to doubt small nonavian theropods relied largely on little mammals, reptiles and insects etc. Most mammals are thought to have been nocturnal, whereas dinos were diurnal. Aves probably ate insects and other small nondinosaurian prey. That’s probably why neornithines survived the K-T while small theropods didn’t. The latter were too dependent on other dinosaurs, which vanished. ”
“In fact, oviraptorids may have eliminated a large percentage of nests before the infants could emerge. As soon as they did, IMO, ornithomimids, troodonts etc made short work of most of them. ”
“or that large theropods would only eat juveniles during difficult conditions.”
Near enough….
“Isn’t it possible that, as a drought wore on, the large prey, with its greater food/water requirements, was the first to die, and the small prey last? So that, the large theropods, prior to their own death, were reduced to eating small/juvenile prey (subsequently fossilized as stomach contents/coprolites)?”
“Specialized LK nest raiders/juvenile eaters seems reasonable considering that egg laying, producing numerous offspring, was far more widespread in the Mesozoic than in recent mammal dominated environments.”
But again, ther’e snot support for this. You are jsut assuming it must be true and evolution doesn’t work like that.
I’m glad you are reading stuff, and thank for accepting that I don’t want to go down this route. Obviously I go to a lot of trouble to try and communciate science well, I’m interested in it, but you have to try and meet with people when discussing things liek this with an expert. You did start off criticisng my interprestation of my data and my hypothesis without reading my work or the blog post (easy enough found) which does not help. You have then thrust more and more stuff at me without ever laying out what your position actually is or what it’s based on rather than a few rather poor assumptions (arms races had to happen, things had to specialise, certain clades were specialised in certain ways) and little or no evidence. Criticing my position without knowing what it is or what it’s based on or trying to find out until your last post when you said you’d google the paper. See why I struggle to motivate myself to deal with all of this.
I’m glad your interested, that’s good and thanks ofr being understanding, but this is, frankly, tiresome. You’ll get more out of books and more generalised idsucssion that either of us will from this kind of conversation.
Cheers,
Dave
Giganotosaurus most likely would anonymously win against an common male tyrannosaur. Considering that tyrannosaurus rex’s common skull fragments lengthen to 4 ft.
Err, really not sure why you think a male makes any differences since there’s no good evidence to determine the gender of either taxon and the skull shown above is the largest known Tyrannosaurs and is clearly no bigger than that of Giganotosaurus.This kind of thing is, in any case, academic to the point of uninterest really.
A chapter in TYRANNOSAURUS THE TYRANT KING concludes the female T. rex was the robust morph, the male more gracile, so I think he means, on that basis Giganotosaurus would’ve probably beat the male. But it’s academic and silly.
Yes but several other analyses have concluded that they can’t be told apart.
I think we need a better sample size than we currently have and especially more information on the possibilites of medullary bone. Telling males from females is notoriously difficult in the fossil record without good reason to pin a definitive gender on one morph or the other – there may well be a robust and gracile morph for Tyrannosaurus, but it could be two different species, or subspecies, or chronospecies, or growth phases etc. as well as just maybe being male and female. There have been plenty of statements to this effect in the past only for them to be overturned or multiple other possibilites to turn up with better evidence. It’s a possibility, but IO think not much more than that right now.
They both will be intentionally manipulated in wounds. For now its remaining fragmental description vs remaining fragmental description of both theropods. Inconclusively the region of which they both existed were departed from time and area of which they were unearthed. The remaining fossil fragments are of the compare method, from fossil duration and elements that describe the years of existences to the physical description. The average tyrannosaur skull, 4 ft (1.4 m), fossil ranges most commonly consists in the late Mesizoic era, within the Cenomanian (about 67 million years ago), associated with the connection of the usually lost bones to incomplete the dinosaur. Within the North American area, founded and described in the late 1800s. The average Giganotosaurus is 6 ft (1.9 m), fossil ranges up to 97 million years located in the Late Mesizoic era, with in the Cenomanian. Discovered and described within the late 1900s. Giganotosaurus: less known, giant carcharodontosauridea theropod. Largest jaws of any known theropod. 8 inches of thin teeth add a more devasting display for slicing and manipulating. A skull case with primarly 3 noticable orbits, either hallow or heavy in weight. Over 47 ft long nearly at the largest and 8.8 tons. Approximatly 6.5 foot skull at the largest. Tyrannosaurus: most known. Large thick skull. 6 inches of thick blunt teeth than are famously known to crush or numb internal harden tissue. A heavy skull in weight. Over 40 ft in maximum size for a female and 6.8 tons. Skull reaches up to 5.3 ft. Fossil features are most used to determine the comparison of the species.
Lol, 67 million years ago is Maastrichtian not Cenomanian.
The Maastric, The Cenomanian; there both within the same time period, the Cretaceous.
Of course but the former was at the end, the latter around the middle-late.
Altogether there within the era of the climatable Mesizoic. The paleoeras in which the scientifically described eras were in for the first place.
I think the correct spelling is Mesozoic. 🙂 Btw anyone remember “giganto wasn’t rex enough?”
oh what an awesome blog…
how can i fallow new entries?
Well you can keep coming back regularly! But there should be a ‘subscribe’ button hanging around.
Pillard: Sure I remember that.
Hello Dr. Hone, I’m only 12 years old but i am a dinosaur freek and you are the coolest person ever. My favorite dinosaur is zhuchengtyrannus magnus, I’m even doing a presentation on the dinosaur in 4-h. thankyou so much for clarifying the true facts because media get’s nothing right. oh yeah, and is it bob nicholls or is it robert nicholls that made the first reconstruction of zhuchengtyrannus magnus?
Thanks! That’s the first thing I’ve had that’s close to fan mail after all these years!
Robert Nicholls is often called Bob, it’s the same guy.
Good luck with your presentation and glad you like the dinosaurs.
“My favorite dinosaur is zhuchengtyrannus magnus,…”
But it’s only known from jaw fragments. Shouldn’t a dinosaur be better known before deciding whether it should be a “favorite”? lol.
It’s still my favorite dinosaur despite little remains. but if that doesn’t count than my favorite dinosaur is ceratosaurus. and thanks again for clearing that up for me.
Well, ceratosaurus covers a lot of species, so particularly Ceratosaurus nasicornis.
Why Ceratosaurus nasicornis? Because of its horn? Bakker suggested Ceratosaurus ate aquatic prey, so compared to “big al” it doesn’t seem very impressive.
Well I suppose a tyrannosaur adapted, presumably, to handle Shantungosaurus is entitled to fans. 🙂
ok, but i still like zhuchengtyrannus magnus or tyrannosaurus zhuchengensis
That’s what I was referring to above. Zhuchengtyrannus lived in the same environment as Shantungosaurus. Btw check this blog. There are some interesting discussions:
http://ffd2009.multiply.com/
because it’s so agile and yes the horn as well and last year i did a presentation on fish eating dinosaurs and no i guess it’s not as impressive as big al but so?
Thanks for the site I’ll check it out.
I guess Austroraptor was the last of the theropod fish eaters.
I thought megaraptor was. And on my presentation i received second place out of 183 different people. I won $250.
thankyou dr hone
No problem, and well done.
thanks
Wow that was unusual. I just wrote an extremely long comment but after I clicked submit my comment didn’t show up. Grrrr… well I’m not writing all that over again. Anyway, just wanted to say excellent blog!
Well it wasn’t me – noting stuck in the comments awaiting approval. Thanks for the n cie words.
I took, the liverty to actually get the scales “exactly right” for you.
This is what I got.
Please don´t hate me.
You can see that they have the largest meassurements for each skull to date. And they have been scaled accordingly with the computer.
-I probably won´t be back to read your replies, but meditate on that picture.
I don´t see how it could be wrong.
The biggest of them all was Spinosaurus period. That s it.
I have already compared these two super-predators on my site: http://dinoabout.blogspot.com/2011/12/dinoabout-fight-night-round-1-t-rex-vs.html
Hey Dave, I really like this site, and how you break things down for people who have an interest in Dinosaurs.
Some ideas I wanted to run past you, I’m sure others have thought of these before, but I’m not sure exactly who’s they all are.
One of them pertaining to the largest dinosaur carnivores in general, but more Tyrannosaur specific.
1) Concept of the largest theropods and T.Rex. So far as we know these guys kept growing most of their lives right? We have only limited remains, even for say T.Rex, what is there? Few dozen specimens, and very few relatively complete ones? I mean if I randomly picked humans out of one city of a population of say 100,000 people, while I would get a decent clue as to the average adult size, would I really know the absolute limit a human could grow to? Even discounting humans with growth disorders, there is still a lot of variation in absolute adult size in most modern animals, and the big mammals don’t even grow their entire lives as dinosaurs did (correct me if I’m wrong on that too). My suspicion is that some specimens of T.Rex, Ginganotosaurus etc… likely grew up to, or close to the physiological limit for a bipedal animal. These truly huge, absolute largest specimens were simply so rare that their chance of fossilization which is also rare, simply did not coincide.
2) Looking at T.Rex, my suspicion is that these were generalists who still did not like to endanger themselves. T.Rex was relatively smart for a dinosaur, and I cannot see a lone T.Rex attacking an adult bull triceratops. Now a Juvenile separated from the herd? That one is a great target. One that is injured and cannot keep up with the herd? Also a good choice. All a Rex has to do, in those cases would be one bite, and quickly get away. The resulting infection and blood loss would soon, perhaps a few hours, put the animal into a state of shock, or at least sick enough to the point it could not defend itself at all, and T.Rex comes back to feed, risk free. Its a cheap tactic, but it makes a lot more sense than a T.Rex going one on one into mortal combat with an adult healthy bull triceratops, which I think is silly, and I think T.Rex would not even consider.
3) The above theory, I call being the cheapest bastard in the forest, does not well to give a good reason for T.Rex’ massive size however. It would make more sense for a more agile horse sized theropod to deliver the quick in and out bite. Now if they lived in family groups, Mom and her kids at the least, and a decent size family with different year classes all living together, then we have a situation where more agile sub-adults can use speed to make an infectious bite, on an already easy target, and then the larger family members could lumber on in and enjoy the family meal and they would be able to discourage other predators from trying to take away the kill. The whole family gets to eat. This “bullying” tactic to take kills away from other predators, as well as keep other predators from taking your families dinner away, seems like a winning survival strategy as well as an evolutionary push toward larger and larger size. Speed may be lost as the animal grows larger and more powerful, but if you have smaller faster family members to do the killing you don’t have to be very fast. It also allows for a greater absolute size, as even if you have grown far to heavy and slow to chase anything down, you are still getting to eat.
Its all speculation, but for some reason they were able to grow quite large, which would obviously reduce top speed, and increase risks of moving fast at all. Yet they were still managing to get food to keep on growing despite being big and slow.
I don’t know why some people get so upset at the idea of T.Rex being a scavenger, or preferring weaker targets, like the young or the injured. Its a great way to make a living. It also does not mean that Rex was a wimp either, which I think is what people are really upset about on the scavenger/weakened prey idea. Far from it. I’d bet money Rex was no wimp, Even though it may have given up stealth hunting in exchange for large size and power, I surely would not want to get close to it. I bet other faster stealthier theropods stayed the heck away from it, and never would want to fight it. When those smaller ones theropods made kills I’d bet it was only a matter of time before the king came to collect his taxes.
Lions and Hyenas are kill stealers too. So will large bears take kills from wolves. Scavenging in this way is hardly the behavior of a weakling, in fact in this sense scavengers are more dangerous than purer predators. Cheetahs are a great pure predator, they have great speed and stealth for killing, but they don’t have the power to back it up if a Lion comes a long and want to take the kill away for itself. Cheetahs would have a hard time making it as a scavenger because they lack the brute force and power a land scavenger needs.
Apologies for the short reply, but well, that is an awful lot and I am busy.
1. Yeah, I’m sure there were bigger ones than we know of, though how much bigger is another question. Assuming they did have inderterminate growth (and that’s no certain) it would have slowed enormously later in life. I’m sure there were bigger rexes than Sue say, but I doubt they got to 15 let alone 20 m.
2.You don’t need to be smart to attack juvies. And see my paper (and posts) on juvenile hunting. Personally I’m not a big fan of the ‘bite and wait’ model, it’s not a common way of doing things and arguably tyrannosaurs don’t actually have a great set-up to practice this.
3. Such family / social groups are very specialised and such a predation split of responsibilites has obvious ecological problems. And yeah, of course they were predators and scavengers, see, ohhh lots of papers, including those by me and a great review by Tom Holtz.
Thanks for the quick answers at least.
1. Yeah, 15m does sound a bit too big, but I could see 13 or 14m. Much bigger it would be so heavy that moving around would get too difficult? The idea is that all of the “biggest” may have had a similar top end weight, as there is a physiologic limit to how heavy a biped is going to get. Or in other words there may not have been that large of a difference in the heaviest T.Rex and heaviest Giganotosaurs, as both were bipeds, and would therefor have similar limit in mass.
2. You’re theory on it prefering the young, as they are easier targets; does that also include the injured adults? Would it make sense for T.Rex to attack an injured adult over the choice of a healthy young one?
In this hypothetical situation you have a Hungry T.Rex, and there are two possible targets. One if a younger animal, its horns are not fully developed, the other one is a fully grown adult, but it is limping badly with a broken front foot?
From what I know, the largest current T.rex is UCMP 137538 which is 14+ meters.
MOR 008, UCMP 118742, MOR 1126, and MOR 1152 are all bigger than Sue. There might be a few more in that range too, but I don’t have the complete stats.
One thing people tend to over look about Sue is that its not really big, but just really old. Growth slows to a crawl around 19 years old, but they still do continue to grow. Sue is 28 years old, and a few tyrannosaurs were around Sue size at 18/19 years old.
Oh yeah, that image I posted is the foot of UCMP 137538. The black foot to be exact compared to Sue’s foot.
So in other words, Sue was a big gal, but we know of one that could have been 14.4 meters (47ft)?
Wait a second, if a 40 foot Tyrannosaur is 7 tons, then wouldn’t that make a 47ft Tyrannosaur around 11 tons? (based on weight cubed root divided by lengtht, x new length cubed) That sounds a little too big doesn’t it?
Are we sure that UCMP 137538 bone is from a Rex?
If so that is sort of black Swan on the topped out at 14m theory.
No, Sue was an old gal, not a big gal.
UCMP 137538 is definitely a T.rex. It’s been around for a very long time, but its stats were only recently revealed in the cannibalism in tyrannosaurus paper.
11 tons is not out of the question considering the recent research says Sue is AT LEAST 9 tons.
That’s big! Keep in mind that 11 tons estimate is based on the outdated 7 ton estimate for Sue, so even that 11 may be too light. My only issue believing a T-Rex could get so large, is how on earth could it hold itself up?
Is there any good math on a physiologic limit to a biped’s mass?
Also, for the length estimates of these dinosaurs have the soft tissue cushion of cartilage between vertebrae and other bones been factored in?
Having even 1 cm between each vertebra could add a whole meter or more on the longer dinosaurs, compared to how the fossils and casts tend to look, due to the bones being put flush with each other, unlike in life where they obviously would have had some cartilage there.
BTW Zhen, I watched your video on UCMP 118742, I liked it a lot, and thanks for putting up something that can be easily shown to people who think Giganotosaurus was grossly larger than T-Rex.
Dunno if the robust and gracile forms really represent sexual dimorphism, or different species. I understand a new paper will address this, possibly in favor of the latter view. 🙂
So, T-Rex technically wins? For now anyways, until we find larger specimens of gigantosaurus?
If you already answered this, sorry. I tried to read all the posts, but I might have missed some. So, Rick Bakker has put forth that T-Rex might have been more of a scavenger. To me, this might explain the density of the T-Rex skull. An hyaena has a massive bit-force, to crunch through think bone that lions can not. What are your thoughts please. Thank you
Well Horner said they were pure scavengers. Not sure what Bakker’s take was as I really can’t remember. They were clearly doing both, but in what proportion it’s hard to say.
“Rick” Bakker? I thought it was Robert Bakker. He favored a predatory T. rex.
I stand corrected! You’re right, it was Horner not Bakker that favored a scavenging T-Rex. Mind is the first thing to go. Yes, I’m sure both hunted and scavenged. Sure they were opportunistic-they won’t turn up the chance at a free meal 🙂 Thanks for your answer
Truly G. carolinii was the longest Theropod to 14m? I thought it was the Spinosaurus to 16m, and G. carolinii was the second or third (depending on how big SMG din-1). There has been some new discovery?
I am a bit sceptical about that scale (full-body outlines, not the skulls).
If you add up leg lenghts, the Giganotosaurus is about the same height as sue (of course these are for comparison-purposes and only approximations):
For Giganotosaurus mean femur lenght (143+137)/2 between the figures from Coria & Calvo/Carrano et al., is 140cm vs the mean of 131 and 138 (I don’t actually know were the latter comes from, any ideas?) which is 135cm
tibiae are 112 vs 114cm
Metatarsals are tricky to determine, there unfortunately doesn’t appear to be an Acrocanthosaurus specimen with complete femur and metatarsal III, and even tough they are apparently known in Giganotosaurus they are undescribed and unmeasured.
MUCPv-95 however seems to be at least a bit bigger, hence it should also be taller.
13-14m sounds like a good size range to me. I am not sure about weight, but I think MUCPv-95 would also be a bit heavier than Sue. The latter is more bulky, no question, but how much exactly remains to be determined. Also, Carnosaurs seem to have higher densities than tyrannosaurs, with the notable exception of MOR 555
(Bates et al., 2009 on the weights of cretaceous american dinosaurs PLOS, Bates et al., 2009 on the weight of Allosaurus MOR 693, Palaeo Electronica, Hutchinson et al., 2011 on body mass of T. rex PLOS)
I was able to reproduce the skull-comparison fairly well with my own conservative and liberal reconstructions based on the quadrate size from Coria & Currie, 2001:
However I think the gaping mouth makes FMNH PR 2081 seem larger and more massive than it really is.
I also think Spinosaurus should be taller, but I heard about some upcoming research suggesting a short-legged animal so we’d best wait for that to get published.
Giganotosaurus was taller larger and heavier than T. rex and possible stronger also giganotosauruz can be also out smarting T. rex silence he is more skill full its brain might be bigger than a quarter of a tv but it will still be smarter its brain size can be bigger than the T. rex silence giganotosaurus can use it better
Also giganotosaurus can grow big as a fully grown spinosaurus.
fuck you guys giga has more brain size you see the t rex space for brain is so smalli mean look at the scale and i sawn on documentary also that they asy giganotosaurus is acctualy smarter than t rex and has a more bigger brain size even tho some say that jiganotosaurus has a size of a banana maaybe but at least is fater and larger brain than the t rexes one plus the skull of giganotosaur is 6 and t rexes is about 5 so giga wins so many peaople agree and yes its brigher more ueful built stronger ore taller larger and more longer tail and neck head arms and stronger at its jaws and teeth plus its eye site is ore better. hes a better hunter.
Cosmin, it is very rude to swear on forums of scientific discussion, but most importantly no one said anything of offence to you to make you have such an outburst. This is merely a place to discuss an argument that has spouted through out the dinosaur community, and yes giganotosaurus is larger then T Rex, but as David Hone stated T Rex has a unique and very powerful bite and would have had more advanced eye sight and intelligence. Although I am not one to participate in these arguments i do find your assertians and language to be rude and unecessary. Please be politer in future.
Why did tyrannosaurs evolve larger brains than other large theropods? Why were they selected for in the Maastrichtian but not Kimmeridgian
or Cenomanian?
In the majority of animal taxa there’s an evolutionary increase in relative and/or absolute brain size. This factor can vary vastly and is hard to compare among different taxa (eg. T. rex-ceratosaurus/raptor-monitor-lizard/felid-crocodilian).
As to your second question, imo they were at the right time and in the right place. Maastrichtian North America (and, to a lesser degree, Asia) were habitats where large, relatively fast Hadrosaurs and very robust, armoured or at least very bony Ceratopsians and Ankylosaurs roamed the landscape.
My hypothesis is that after the C/T event (I mean Cenomanian-Turonian, just to make that clear) the highly cursorial built of Tyrannosaurs was an evolutionary advantage over other contenders that could have filled the large-predator-niche, because more so than before the main prey item were fast-moving animals (various ornithopods) while sauropods and Carnosaurs were declining in Laurasia.
Later (which is the time were tyrannosaurinae evolved) Armoured prey started to diversify, favouring the developement of more robust dentition and crushing bites to counter the bony structures obstructing the acess to vulnerable areas of their prey.
I was aware of the reasons why tyrannosaurs became top predators in Asia-american environments, post Cenomanian transgression. Faster speed and stronger biting power was needed to deal with hadrosaurs and ceratopsid/ankylosaur prey respectively. But why the bigger brains? T. rex is said to have had a brain twice as large as that of the comparably sized C. saharicus. By the time the latter appeared, carcharodontosaurs had existed since the time of Veterupristisaurus about 60 million years earlier (and probably prior to that). Why did they manage so long with modest brains whereas “tyrant lizards” evolved bigger ones?
Neural advancement in tyrannosaurs may have to do with eye sight. We know that birds are fairly intelligent so as a reference there might be a link with increased sociability (detecting dinosaur body language through sight or sound,) color recognition (looking at a mate-feathers might have helped due to the rapid evolution of tyrannosaurs,) predation (resource partitioning? Opportunized pack hunting? Calculating/sizing up prey?)
Since tyrannosaurs had strict competition as evident by their cannibalism, such harsh conditions may have resulted in only the fittest tyrannosaurs becoming selected for breeding. Possibly the apex individuals in the tyrannosaur community were the ones with the most appealing appearances and social compatibility that may have described the individuals proficiency in parenting.
My best guess is parenting. Parenting is a HUGE indication of intelligence and neural development one thing that distinguishes birds from the lower reptiles. Even crocodilians exhibit higher intelligence apart from the other reptiles and have significant parenting abilities. Fossil remains of cannibalism may even be interpreted as infighting due to protective-parenting like a mother bear possibly.
From what I’ve heard, most of the Tyrannosaurus brain consisted of visual and olfactory lobes. The cerebrum didn’t amount to much. It’s possible Tyrannosaurus need more acute senses and better processing of sensory information to find prey (like hadrosaurs, which tried to be elusive) whereas this was less of a problem for the big sauropod hunters like this newly named Siat. (I assume it went after Abydosaurus or its young).
The forward facing eyes of Tyrannosaurus may support this interpretation. Bakker btw mentioned forward facing ears.
true , T-Rex skull was larger . it was a lone predator unlike the giganotosaur and hence needed the large crushing bite force to take down prey. Having excellent vision ( as studies suggest ) they were nocturnal predators.
giganotosaur on the other hand was considered to be a pack hunter ( much like the Allosaurs ). Hence it probably needed jaws for ripping and scraping flesh so that prey would eventually succumb to blood loss. ( Much like how the Allosaurs hunted Diplodocus ). Maybe the size of the brain may have been small .BUT pack hunting shows that it probably had a VERY high level of intelligence.
I don’t think the skull of Tyrannosaurus was larger overall than that of Giganotosaurus even if it was more robust. We don’t know if Tyrannosaurus was a lone or pack hunter. There is evidence T. bataar lived and hunted in groups so maybe the closely related Tyrannosaurus did the same. A big brain isn’t necessary for living in groups.
Similarly fossil evidence in Alberta show that Allosaurs lived in packs. Giga was an allosauroid. Hence like T.bataar hunted in groups, Giga probably did too ?. Maybe t – rex did too? . Also i would like to make another point. Yes the skull was robust. According to scientific estimates, the Allosaur had a weak bite force ( less than todays lions ! ). The skull may have been longer than T-Rex but was pretty narrow in comparison. studies show that muscles of the skull were arranged in such a way that it could stretch its skull very wide and then clamp down on its prey sort of like an axe. this helped it to multiply its bite force several times the normal.
Also gigas bone density was not SO low that it could not withstand the crushing force of its own bite. It was pretty reasonable. !. Enough to bleed victims to death after a few good strikes to vunerable regions.
Allosaurs in Alberta? Or Albertosaurs? There is an albertosaurus bonebed in the Horseshoe Canyon. Dunno if it’s proof of pack behavior but it’s evidence.
OOPS!! not Alberta. My mistake… I meant in Cleveland–Lloyd Quarry.
IIIRC Cleveland Lloyd quarry represents a predator trap. If so, the accumulation of Allosaurus remains there can’t be taken as evidence of gregarious behavior or packs. Predator traps are a magnet for infirm hunters and I perceived some evidence for that at cleveland lloyd.
Oh yes! I just read about it.. maybe they were there to feed on weaker ones. Got trapped there and died. Yes you may be right. Sorry my mind was clouded by walking with dinosaurs and big al’s pack in the documentary. I watched it as a kid ( lol). In fact bite marks on the body probably showed they were defending territory and were hence solitary creatures. hmm…
Ken Carpenter’s study may shed light on why a big Allosaurus ended up at Cleveland Lloyd. I mean the proximal caudal with the puncture wound.
What do you think of this blog post? It isn’t often a dino post appears there.
http://starvisions.blogspot.com/