Tyrannosaurus Tooth Found Embedded in Hadrosaur Tail

[Patrx]

http://westerndigs.blogspot.com/2013/07/t-rex-tooth-found-in-dinosaurs-tail.html

I was under the impression that such finds had already been documented? At any rate, this will be a handy find to point to whenever this "debate" arises in the future. Evidently, the tooth was from a subadult Tyrannosaurus, which is interesting.

[amargasaurus cazaui]

From what I have understood there have been fossils found that show evidence of having been bitten, and the impressions of teeth marks and crushing and scratching that imply the animal had been fed upon . I even own some myself. The unique thing about this find is that A) they also found the tooth itself imbedded within the bone, and B) that the bone shows healing after the bite. While there are many fossils that indicate healing after the animal had been bitten, the broken off tooth within the wound is unique , when placed in combination with a healed wound. This somewhat proves the animal was bitten by a Tyrannosaurs while alive and the animal escaped and healed, rather than the predator feeding on a carcass. I do not myself know of any paralell to this having been found until now.

[wings]

I was under the impression that such finds had already been documented? At any rate, this will be a handy find to point to whenever this "debate" arises in the future. Evidently, the tooth was from a subadult Tyrannosaurus, which is interesting.

You're probably referring to this paper (http://www.arca.museus.ul.pt/ArcaSite/obj/gaia/MNHNL-0000778-MG-DOC-web.PDF , figures 3, 4 and 5) by Carpenter. However, no tooth found associated with this specimen.

[Everything_Dinosaur]

We just put together a quick blog article on this new paper, linking it to previous evidence of Hadrosaur (specific to Edmontosaurus) pathology that might also indicate active predation by T. rex: http://blog.everythingdinosaur.co.uk/blog/_archives/2013/07/16/t-rex-tooth-crown-found-embedded-in-an-edmontosaurus-tail-predatory-behaviour.html

[Everything_Dinosaur]

It is certainly an intriguing find, we have been corresponding with BHI over a number of matters and we find that "Palaeo Pete" has surprised us with this one.  Not quite the "smoking gun" evidence, one can conclude that his is a bite from an immature, sub-adult Tyrannosaurid, most probably T. rex and the Edmontosaurus lived to tell the tale, but is this hunting behaviour or some form of other interaction between these species?  How often did such behaviour take place?  Personally, I think that T. rex was very probably an opportunist feeder, but a cool fossil find and academic paper nonetheless.

[wings]

... is this hunting behaviour or some form of other interaction between these species?...

Just curious to know what other interaction would you be referring to? Are there any modern analogs to what you might be referring to?

[Everything_Dinosaur]

The problem we have is that the fossil evidence can be interpreted in many ways, and it is all too easy sometimes to make assumptions and to draw conclusions based on the limited material that we have.  For example, this is a single tooth embedded into a Hadrosaur's tail, it indicates a bite, the tail bones are fused, the pathology has been noted.  However, it is difficult to state categorically  that this was an attack with the intent to kill and eat the victim ie. evidence of attempted predation,   I have seen spotted hyena bite the tail of a Nile Crocodile, I seen a horse bite a donkey, I have observed a water buffalo attempt to gore a young zebra.  If these animals were to become fossilised and evidence of trauma was preserved in the fossil record, then, if we did not have knowledge of the extant animals we could jump to conclusions about how these animals behaved.  Personally, I believe that T. rex was an opportunist feeder, scavenging when it could but also hunting.

[CityRaptor]

Most if not all of those named example are probably conected to rivalry, but in this case we have a Herbivore and a Carnivore, therefore likely a Predator-Prey-Relation.

It atleast confirms that sub-adult Tyrannosaurus were active hunters.

[Seijun]

I can think of scenarios where a trex might have to bite a hadrosaur for a reason other than hunting. Suppose the hadrosaur felt threatened in some way and went on the offensive, forcing the young trex to fight back? It is not unusual at all for herbivores to go after carnivores, even if the carnivore does not pose a direct threat. For example, if the herbivore had young nearby. Or suppose the trex was attempting to scavenge a dead or dying hadrosaur and was attacked by the still-present herd? Personally I like to think that the trex was actively hunting the hadrosaur, but ED makes a good point that without anyone being there, it is impossible to know with certainty what happened.

[wings]

I can think of scenarios where a trex might have to bite a hadrosaur for a reason other than hunting. Suppose the hadrosaur felt threatened in some way and went on the offensive, forcing the young trex to fight back? It is not unusual at all for herbivores to go after carnivores, even if the carnivore does not pose a direct threat. For example, if the herbivore had young nearby. Or suppose the trex was attempting to scavenge a dead or dying hadrosaur and was attacked by the still-present herd? Personally I like to think that the trex was actively hunting the hadrosaur, but ED makes a good point that without anyone being there, it is impossible to know with certainty what happened.

But in saying this, didn't we go back to the beginning again? Seijun's idea could well be possible but do we have any analogs/examples of this where the "carnivore's" teeth is lodged in a "herbivore's" skeleton via a defensive action? It seems the damage is unusually deep for a defensive wound as the tail section shown seems to be approx. mid way which is still quite thick. I suppose anything is possible but perhaps modern day examples of such deep wound via a defensive action is rarely documented.

[Minnesota Jones]

Very cool news.  But yes, all this is truly is that at least one Tyrannosaur bit a living animal that lived to tell the tale... or is that tail?  Ha!  Funny pun... ugh!

I'd love hard evidence to prove T. rex hunted like we all believed as children.  But this is definately a good piece of circumstancial evidence for it.  Teeth marks on prey have proved T. rex ate meat, but not that it hunted.  But a piece of a tooth in a prey animal that got away is a wonderful piece that tells a story.  Too bad we don't have more of that story.  Like how fossil footprints show something the animal did, not just what they looked like.  This is another great "frozen moment in time" fossil!  Maybe someday we'll get more evidence to help support it.

[Gwangi]

I think this is about as good as it gets when it comes to evidence for active hunting in an animal that has been dead for 65 million years.  Could the bite have been the result of some other kind of encounter? Sure! But I'm going to pull out Occam's razor on this one and assume this is evidence of hunting behavior until evidence surfaces that suggest some other less likely explanation.

[suspsy]

The problem we have is that the fossil evidence can be interpreted in many ways, and it is all too easy sometimes to make assumptions and to draw conclusions based on the limited material that we have.  For example, this is a single tooth embedded into a Hadrosaur's tail, it indicates a bite, the tail bones are fused, the pathology has been noted.  However, it is difficult to state categorically  that this was an attack with the intent to kill and eat the victim ie. evidence of attempted predation

Occam's Razor dictates that the simplest explanation is the correct one, i.e., the T. rex was attempting a kill.

I have seen spotted hyena bite the tail of a Nile Crocodile

Not the same.

, I seen a horse bite a donkey

Also not the same, what with both being herbivores.

I have observed a water buffalo attempt to gore a young zebra.

The furthest example yet. Doesn't even involve biting.

You say that it's all too easy to jump to conclusions, yet the alternatives you offer frankly come off as very far-reaching indeed. Especially considering that there is a previously existing Edmontosaurus skeleton with a similar healed wound on its tail and a Triceratops with a damaged frill and a broken horn. I find it extremely hard to believe that these are all examples of anything but predation.

[Seijun]

Again, the point was, just because there is evidence that a herbivore was wounded by a carnivore, it doesn't automatically mean that the carnivore was trying to hunt and kill the herbivore. I agree that hunting behavior was the most likely reason for the injury, but all we can know for 100% certain was that a young trex bit a hadrosaur on the tail. The exact circumstances leading to that even can never be known.

[suspsy]

I absolutely fail to see any harm in concluding that it was indeed predation. None whatsoever.

I'm with a lot of paleontologists who are completely sick and tired of the whole predator/scavenger debate. All available fossil evidence points very clearly to a lifestyle that combined both feeding methods. Why can't everyone simply agree that that was how T. rex lived instead of scrambling to come up with alternative explanations every single time we discover a fossil with a healed injury inflicted by the tyrant king? What is the point?

[tyrantqueen]

I absolutely fail to see any harm in concluding that it was indeed predation. None whatsoever.

I'm with a lot of paleontologists who are completely sick and tired of the whole predator/scavenger debate. All available fossil evidence points very clearly to a lifestyle that combined both feeding methods. Why can't everyone simply agree that that was how T. rex lived instead of scrambling to come up with alternative explanations every single time we discover a fossil with a healed injury inflicted by the tyrant king? What is the point?

Yeah, I agree. If it was any other theropod I bet no-one one would have any problems in declaring it as active predation. For some reason, some people can't let go of the scavenger theory for T.rex and don't want it to be an active hunter. No offense to anyone though.

[Seijun]

Im not one to try and argue that trex didn't hunt, but it is a pet peeve of mine when a fossil is found where two dinosaurs are together or a tooth or broken bone or claw mark is found somewhere and people point and say "there, that is the smoking gun, this and this and this MUST have happened!" Well, no. In this case, predation is the most likely, most plausible explanation, but it bothers be when people act like that is absolutely the only explanation It would be safer to say that this is extremely good evidence that trex was an active predator, rather than saying it means beyond any doubt that trex was an active predator.

[Everything_Dinosaur]

The point that we are trying to make involves the interpretation of evidence, the examples given reflect the fact that if any of the pathology from these specimens was to be preserved in the fossil record, then that evidence has to be interpreted and it can be interpreted in many ways.  With a science like palaeontology, we lack first hand observations and as a result we have theories whilst, in contrast, mathematicians have the luxury of theorems.

[wings]

Im not one to try and argue that trex didn't hunt, but it is a pet peeve of mine when a fossil is found where two dinosaurs are together or a tooth or broken bone or claw mark is found somewhere and people point and say "there, that is the smoking gun, this and this and this MUST have happened!" Well, no. In this case, predation is the most likely, most plausible explanation, but it bothers be when people act like that is absolutely the only explanation It would be safer to say that this is extremely good evidence that trex was an active predator, rather than saying it means beyond any doubt that trex was an active predator.

Not everyone is saying it's an absolute on whether tyrannosaurs are predators/scavengers or not but from what we have we just don't have much of modern analog of such occurrence other than predation perhaps?

[suspsy]

The point that we are trying to make involves the interpretation of evidence, the examples given reflect the fact that if any of the pathology from these specimens was to be preserved in the fossil record, then that evidence has to be interpreted and it can be interpreted in many ways.  With a science like palaeontology, we lack first hand observations and as a result we have theories whilst, in contrast, mathematicians have the luxury of theorems.

Again, the problem with the examples you gave is that one involved a known predator biting another known predator, one involved a known herbivore biting another known herbivore (and never have I heard of a horse biting a donkey with such strength that it damaged bone), and one involved an herbivore goring, not biting, another herbivore. Not one of your examples goes in the same category as a T. rex biting an Edmontosaurus. A better comparison would be a Cape buffalo surviving a Nile crocodile attack or an elephant seal surviving a great white shark attack. I've seen plenty of examples of the latter first hand during my trips to California, and none of the marine biologists I know have claimed that it was an error or unnatural behaviour on  the shark's part.

If the fossil in question was the only piece of evidence of predatory behaviour in T. rex, I would be more inclined to accept your argument. As I have already pointed out, however, it is not. I have a lot of difficulty swallowing the notion that three T. rexes in different parts of North America at different times all made the "error" of biting another dinosaur with such intensity that it left permanent physical scarring.

It's bad enough that Jack Horner is so stricken by hubris that he refuses to accept any argument that contradicts his "theory" (and no one should forget that he's never had the dedication or the courage to actually produce a proper paper on it). But are people so afraid of leaping to conclusions that they feel obligated to come up with reaching alternatives for every piece of predator evidence that arises?

In closing, I want to state for the record that I'm not making a personal attack against Everything_Dinosaur (I love their site) or Seijun or anyone else in this thread. Again, I'm just fed up with the whole tiresome argument and how the media loves to make a huge deal of it.