Tyrannosaurus rex vs. Ankylosaurus magniventris

[theropod]

True. But the main point is that their osteoderms can withstand bites from other crocs. Ankylosaurus was adapted to live with animals like tyrannosaurus, and its armor made crocodilian osteoderms look like paper. It may have been smaller than the theropod, but its armor served a purpose: to provide effective defense.

But who knows whether this defense was against T. rex? It may have served as protection against a smaller animal whose smaller, less massive jaws would have posed it with greater problems when biting thick armour. Something like Albertosaurus or Nanotyrannus for example.

Not much of that information is given. Ultimately, he survived nonetheless. It can be assumed that the bullets did not enter his body, because such an occurrence was never described.

It should be the default assumption that if someone/some animal is shot the bullets enter its body. I presume if a human is shot and survived, most people will not think "well luckily the bullet didn't enter his/her body", but "well, luckily it didn't hit his/her heart or lung!"

Yes. Plenty of crocodiles have had their jaws bitten off

So, do you doubt a T. rex could crush the skull or armour of a smaller Ankylosaurus?

[creature386]

Oct 13, 2013 23:36:17 GMT 5 Supercommunist said:

Are you talking about that one video with two alligators fighting on a golf course?

No, it is a video called "Gators fight", where you see a battle between two gators in Orlando.

Oct 14, 2013 0:01:55 GMT 5 Godzillasaurus said:

I remember you told me that last year, but some people have doubts about Gustave.

On Carnivora? What was your username?

Jinfengopteryx.

[Godzillasaurus]

But who knows whether this defense was against T. rex? It may have served as protection against a smaller animal whose smaller, less massive jaws would have posed it with greater problems when biting thick armour. Something like Albertosaurus or Nanotyrannus for example.

Large ankylosaurs (the ankylosaurids and nodosaurids) in general were most common during the later parts of the Cretaceous, when large tyrannosaurids replaced allosaurs as the apex terrestrial predators. Tyrannosaurid jaws were designed for direct force, which means that herbivores needed to have adaptations that would protect them from such predators, like heavy armor plating. Nanotyrannus and Albertosaurus were both tyrannosaurids, which means that they both had similar morphologies to tyrannosaurus. Nanotyrannus was more gracile than tyrannosaurus, yes, but that does not mean the two weren't similar at all. Nanotyrannus may have even been a juvenile of a larger genus of tyrannosaurid.

The bottom line is that ankylosaurus evolved alongside large tyrannosaurids, which means that it does not matter whether it was tyrannosaurus, daspletosaurus, or Albertosaurus.

So, do you doubt a T. rex could crush the skull or armour of a smaller Ankylosaurus?

Not really. I was just explaining to you that crocodiles often lose parts of their jaws, because you asked.

[theropod]

Large ankylosaurs (the ankylosaurids and nodosaurids) in general were most common during the later parts of the Cretaceous, when large tyrannosaurids replaced allosaurs as the apex terrestrial predators.

They did, in the regions were ankylosaurs thrived. However I don't see the relevance Allosaurs have here.

Tyrannosaurid jaws were designed for direct force, which means that herbivores needed to have adaptations that would protect them from such predators, like heavy armor plating.

every Herbivore needs some sort of protection from predators. Armour plating would be even more effective at a more gracile-toothed predator, but in response the predator woudl increase tooth robusticity and bite force. It's a two-sided upgrading of weaponery and defense, but no defense is impenetrable, otherwise the predator would have starved.

Nanotyrannus and Albertosaurus were both tyrannosaurids, which means that they both had similar morphologies to tyrannosaurus. Nanotyrannus was more gracile than tyrannosaurus, yes, but that does not mean the two weren't similar at all. Nanotyrannus may have even been a juvenile of a larger genus of tyrannosaurid.

I think we're on cross purposes.

As a matter of facts, Albertosaurus, and probably Nanotyrannus or comparable animals are smaller than T. rex, with smaller and less robust jaws (and yes, despite many paralells there are also notable differences, some perhaps allometric, others perhaps not). This would mean cracking the armour of a large prey item would be more difficult.
Analogy: a jaguar can crack open a turtle shell, the latter doesn't provide complete protection from this animal. A jaguarundi on the other hand cannot crack the shell, it provides effective protection against this predator.

The bottom line is that ankylosaurus evolved alongside large tyrannosaurids, which means that it does not matter whether it was tyrannosaurus, daspletosaurus, or Albertosaurus.

It does matter, see the above example.

The bottomline is, that from a biomechanical perspective it's unlikely the armour of Ankylosaurus would have provided complete protection from a decent-sized T. rex, and even if it did there were regions the latter could bite that were unarmed.

Not really. I was just explaining to you that crocodiles often lose parts of their jaws, because you asked.

Exactly. and that was a rethorical question, I'm well aware of crocodiles biting off each other's jaws. If crocodiles can do that to each other, it's likely T. rex would have no problem crushing the skull of an Ankylosaurus.

[Godzillasaurus]

However I don't see the relevance Allosaurs have here.

Herbivores are evolved to cope with certain predators that they live with and vice-versa. This means that anylosaur armor had a very specific purpose. Tyrannosaurids evolved powerful skulls and bites in response to the armored ankylosaurs (which were existent since the Jurassic). In response to this, ankylosaurs became larger and (possibly) more heavily armored when tyrannosaurids were the dominant terrestrial predators.

But back to the point, allosaurs evolved alongside stegosaurs and sauropods. Allosaurs had thin, knife-like teeth, wide gapes, and proportionally longer forearms than those belonging to tyrannosaurids. This was done in response to sauropod and stegosaur evolution. Notice how carcharodontosaurids became extinct during the middle parts of the Cretaceous? And sauropods became more isolated?

[theropod]

^You just repeated the reasons why T. rex could probably bite through the armour of a smaller Ankylosaurus.

[Godzillasaurus]

SMALLER ankylosaurs... That does not include animals like ankylosaurus and edmontonia

[theropod]

I wrote "smaller Ankylosaurus" not "ankylosaur". Ankylosaurus is smaller than T. rex. I do not assume it's armour would provide sufficient protection against a larger animal, but it may be effective against a smaller type pf predator (eg. albertosaurus, Nanotyrannus...)

[Godzillasaurus]

Well, obviously, no animal is truly invincible from predation; heck, blue whales often get preyed on by groups of killer whales today despite the obvious size advantage of the former. The point being that ankylosaur armor plating and tyrannosaurid crushing capabilities seem to go hand-in-hand.

[Deleted]

Oct 13, 2013 19:03:06 GMT 5 theropod said:

There is evidence for a probable posterior bite force in excess of 5.5t and the ability to shear through big bones and cause deep punctures.
All the ankylosaur's armour will likely not provide effective protection from that, it's just too "small" an animal for that by comparison, and it leaves many areas relatively unprotected, eg. the legs and skull which could be crushed.

However I'd be interested in seeing a comparison with a somewhat smaller T. rex, approximately 11-11.7m in lenght (which is a size range many T. rex are probably in, and which the average of adult femora from the theropod database [1.19m] reflects)

Tyrannosaurus specimen AMNH 5027 and an Ankylosaurus scaled it to a standing length of ~6.25 meters(meaning not the largest known specimen). I made this quite a while ago for the carnivoraforum counterpart of this thread.

[theropod]

Let's put it this way, I definitely favour the AMNH specimen, albeit not for a massive margin, since despite the small size Ankylosaurus remains potentially dangerous.

[Fragillimus335]

From what I can tell the latest 6.25 meter estimates for Ankylosaurus are probably too small. The largest Ankylosaurus probably had a skull ~75-80 cm long. It is 74.5 being pretty eroded and crushed. When I scale most accurate skeletals of ankylosaurus and its close relatives it is ~8 meters long. Still not the 9-12 meter monster that is usually quoted. But big enough to make most Tyrannosaurs think twice.

This Ankylosaurus probably massed 5-6 metric tons.

[creature386]

Do you have a source for that skull length?

[Infinity Blade]

I think the latest size comparison (shown on Carnivora) with these two animals featured a 7 meter Ankylosaurus with T.rex. The former looked as if it were in the perfect position to strike at the legs of the theropod.

[Runic]

Nov 12, 2013 5:48:13 GMT 5 Infinity Blade said:

I think the latest size comparison (shown on Carnivora) with these two animals featured a 7 meter Ankylosaurus with T.rex. The former looked as if it were in the perfect position to strike at the legs of the theropod.

that's cause it's a picture....