Tyrannosaurus Tooth Found Embedded in Hadrosaur Tail

[Dinoguy2]

...The authors of this paper don't seem to have done that. They took the first step of the scientific method, formed a hypothesis, and then *stopped*! Horner is simply taking the next step and proposing an alternative. Is it possible to test any of these? Maybe not. But it is critical for public education that people understand the difference between science and educated speculation.

Are Horner's alternatives more likely? Of course not. But in order to qualify as science, they need to be ruled out using data, not thought experiments. Only then can the hypothesis (T. rex predation on this tail vert) be supported.

Perhaps they can't see any other viable alternatives... they mainly based their reasoning on observation of modern animals; in the paper they said: "...The localization of the tyrannosaur tooth in the midcaudal area of the hadrosaur is consistent with that noted in modern pursuit predator attacks. Kalahari lions have been observed to initially target the hindquarters of the prey animal, in an attempt to immobilize it...". Their finding is very similar to Carpenter (1998, 2013), Murphy et al. (2013) and probably some of the papers listed in the reference section. For the time being we'll just concentrate on these "tail" bites. Hadrosaurians' tails seems to be quite inflexible (Paul 2010) since part of their tails were stiffened by ossified tendons. So their tails are unlikely to be much of a weapon (unlike the hypothesis of the whip-like tail of the sauropods). Would they have tried to confront a tyrannosaur with their back side? Isn't it unusual if they are not facing each other in a "fight" if that is the case? If they are facing one another then why the tyrannosaur would try to bite the back end instead of the front of the animal? These bites are on the rear of the animal so it is likely that when the incident occurred the hadrosaur is running/walking away from the tyrannosaur. I don't know whether this is good science or not but at least they seem to find similar modern examples to support their claim as we don't really have much examples of otherwise/alternatives reported or published to go by yet.

All very sound reasoning. But still zero science. It's not science until you or the researchers propose a way to test these various scenarios and hypotheses.

Thinking things through with logic is not testing. Testing is using data try to and prove a scenario wrong.

Modern analogies are helpful in forming hypotheses, but not in testing them. Horner's complain is that people are going from "form hypothesis" to "conclusion" and skipping the part in the middle called "do science".

Here's how I would do the science: Take all the known hadrosaur/tyrannosaur bite marks. Separate out the ones that are healed over. Look at where they are on the body. Using a statistical analysis, see if there is a pattern? Does that pattern fit the predictions of the "T. rex hunting injuries" hypothesis? In fact, what ARE those predictions. We really need step two, "make predictions that we would expect to see if hypothesis is true", before we can even proceed. Using modern analogies, what would we expect T. rex hunting injuries to look like? Where on the body would they be concentrated? Why would we predict bites would occur more often on the tail than on the neck or back? Somebody needs to figure out a way to approach this rigorously and test it, and frankly I'm not sure doing science here is even possible given the limited data we have. Our conclusion might have to be "huh, that's interesting" rather than "this supports the idea T. rex hunted hadrosaurs by grabbing the tail."

How about injuries from *successful* attacks? Is there any way we can see if non-healed bite marks are stronger on the tail? Do hadrosaurs living alongside tyrannosaurs more often or more likely to have broken/bitten caudal neural arches? These are are the questions we need to answer first.

[suspsy]

Why couldn't the T. rex take a portion of the liver to its family instead of the tail?

err.....have you ever tried holding or carrying a piece of liver? It isnt as easy as it might sound.

err . . . . I'm not a tyrannosaur with an enormous mouth full of banana-sized teeth that's ideal for gripping and holding onto slippery meat. If I was, I'd probably tell you that it was a relatively simple task. I'd also be curious to know how carrying a chunk of tail meat would be any easier.

Then I'd kill you.

Aside from the idea far easier to grab a larger piece of the animal that would provide more food.

. . . are you seriously telling me that the liver of a 30-foot long duckbill would not be a large enough piece of food?

This is a photo of an African elephant's liver (GRAPHIC):

http://i218.photobucket.com/albums/cc160/critcaredoc/ElephantLiver.jpg

Granted, we don't know what the exact dimensions of a duckbill's liver was, but I would wager it approaches that size.

And on that note, this debate has become rather pointless. I'm ending it.

[amargasaurus cazaui]

Why couldn't the T. rex take a portion of the liver to its family instead of the tail?

err.....have you ever tried holding or carrying a piece of liver? It isnt as easy as it might sound.

err . . . . I'm not a tyrannosaur with an enormous mouth full of banana-sized teeth that's ideal for gripping and holding onto slippery meat. If I was, I'd probably tell you that it was a relatively simple task. I'd also be curious to know how carrying a chunk of tail meat would be any easier.

Then I'd kill you.

Aside from the idea far easier to grab a larger piece of the animal that would provide more food.

. . . are you seriously telling me that the liver of a 30-foot long duckbill would not be a large enough piece of food?

This is a photo of an African elephant's liver (GRAPHIC):

http://i218.photobucket.com/albums/cc160/critcaredoc/ElephantLiver.jpg

Granted, we don't know what the exact dimensions of a duckbill's liver was, but I would wager it approaches that size.

And on that note, this debate has become rather pointless. I'm ending it.

I think the point was actually well made . If you can and are able to provide sound arguments that cast doubt wether the fossil proves predation then you have proven that the fossil proves little, and can easily be explained in other ways. I have done so quite well with the points I made, so no, it was NOT a pointless debate. Perhaps we should be arguing due to the lack of fossil pizza boxes, the tyrannosaurus could not hunt pizza effectively. The smaller arms further prove it so it must be.....that is the type of logic given here in the discussion. As Dinoguy said, inference is not science.
Also while it is likely and would seem given, there is NO evidence for liver organs in dinosaurs. There is evidence for tails .
  I am unsure what you meant with your comment about killing me. I will assume it was a good natured joke and you are not threatening me. I think it somewhat comes off as such, so I do hope you did not mean that and just made a mistake.Which segues into my final comment..........you may withdraw from the discussion as you choose, but you are not able to "end" any discussion. I somewhat frown on those that interject the parting shot and then attempt to silence everyone stating ...end of discussion.

[suspsy]

I fail to see how you proved anything, frankly. You made a very passionate case for a tyrannosaur preferring to feast on a tail instead of vital organs, but that doesn't change the fact that it flies directly in the face of how modern land carnivores behave at a kill. Nor does it change the fact that the fossil in question was not of a duckbill that was devoured, but one that managed to survive a bite from a tyrannosaur. Nothing you've written in your posts strongly supports an alternative to predation.

Also while it is likely and would seem given, there is NO evidence for liver organs in dinosaurs. There is evidence for tails .

. . . what?

Are you seriously trying to argue that dinosaurs did not possess livers? Why not toss in hearts while you're at it? Or lungs? Or stomachs?

Putting aside the fact that all living vertebrates possess a liver, there does happen to be evidence of them existing in dinosaurs:

http://en.wikipedia.org/wiki/Scipionyx#Liver.2C_heart.2C_spleen_and_thymus

In closing, if you can't tell that that bit about me killing you if I happened to be a Tyrannosaurus rex instead of a human being was an obvious joke, then there's really nothing I can do.

[amargasaurus cazaui]

Modern land carnivores are almost all mammals. Dinosaurs were not mammals that we are aware of so you cannot use the one to suggest the other realistically. I did give some rather striking possible alternatives to predation, or at least made a strong of case against, as you did for it.

I am aware of  the supposed liver in the specimen you linked to . I Also am aware that at this point is contentious and remains debateable . My original words were
"Also while it is likely and would seem given, there is NO evidence for liver organs in dinosaurs. There is evidence for tails . "
I am stating evidence...proof, not inference and guesswork.I was asking for proof....proof of livers, proof of predation, proof for any of your comments. None exists. None exists for my own either....and that was the point.

As for your "joke" I  will take your word for it. Myself I find it somewhat poor form to tell someone you would kill them in a chat forum, where expressions, and context are  often somewhat blurred. I myself at least am not comfortable with it.

[wings]

All very sound reasoning. But still zero science. It's not science until you or the researchers propose a way to test these various scenarios and hypotheses.

Thinking things through with logic is not testing. Testing is using data try to and prove a scenario wrong.

Modern analogies are helpful in forming hypotheses, but not in testing them. Horner's complain is that people are going from "form hypothesis" to "conclusion" and skipping the part in the middle called "do science".

Here's how I would do the science: Take all the known hadrosaur/tyrannosaur bite marks. Separate out the ones that are healed over. Look at where they are on the body. Using a statistical analysis, see if there is a pattern? Does that pattern fit the predictions of the "T. rex hunting injuries" hypothesis? In fact, what ARE those predictions. We really need step two, "make predictions that we would expect to see if hypothesis is true", before we can even proceed. Using modern analogies, what would we expect T. rex hunting injuries to look like? Where on the body would they be concentrated? Why would we predict bites would occur more often on the tail than on the neck or back? Somebody needs to figure out a way to approach this rigorously and test it, and frankly I'm not sure doing science here is even possible given the limited data we have. Our conclusion might have to be "huh, that's interesting" rather than "this supports the idea T. rex hunted hadrosaurs by grabbing the tail."

How about injuries from *successful* attacks? Is there any way we can see if non-healed bite marks are stronger on the tail? Do hadrosaurs living alongside tyrannosaurs more often or more likely to have broken/bitten caudal neural arches? These are are the questions we need to answer first.

The fossil record is never complete, most palaeontologists would consider lucky even if they can find part of an animal.  So getting a complete specimen would be rare.  Assuming the "unsuccessful" rate is quite high then making a finding would be even rarer (Modern terrestrial predators (e.g., coyotes and lions) fail or abort between 45% and 62% of their attacks). We currently have 5 hadrosaur specimens (including the one in the current paper) of "failed attacks" associated with tyrannosaurs published; as inferred from partial healing of injuries. One of them has bite marks on a rib and another one on the skull while the other three have bite marks in the caudal region. We did not have a large sample size but I suppose it would be hard to ask for more since we often find fossils by chance and sighting. Pattern wise all we can say is that we have 5 animals and 3 of them are injured on the tail. As to what we discussed earlier (in you saying that "...Previous studies have suggested that large carnivorous dinosaurs would have preferentially hunted small or juvenile prey, rarely attacking large adults..."); this is actually true for at least 2 of the specimens that have tail injury. Although Carpenter's Edmontosaurus (DMNH 1493) is an adult; it has a fractured ilium so the animal is likely to be walking with a limp (probably becomes an easier target) and as for JRF 1002, it is just a juvenile/sub-adult based on the degree of ossification found on the animal. The third specimen, we just didn't get enough to tell since all there is are 2 fused tail vertebrae. And these do agree with your "previous studies on potential preys". Due to the sparse fossil find it is probably unlikely that we can establish an exact pattern but the papers on these "failed attack injuries" aren't talking about determining a pattern. They are merely describing these specimens and providing what they inferred as the most reasonable explanation to their finds. Inference from modern analogs is probably the best of what we can do for now. From the way that the bones are sheared off both Carpenter (2000) and Murphy et al. (2013) have determined that the bites are initiated from the rear of the animals. For now, we don't have any footprints on hadrosaurian charging/walking/running backwards and have no modern analogs of any animal with such behaviour as back facing their opponent during a confrontation. The mentioning of the lion example on the current paper or even watching bird hunting videos on youtube (such as eagle catching a hare, though they are flying but the idea is very similar where the eagle comes in from the victims's "blind spot" and not in their viewing field area) you would find that predators coming from behind to catch their prey is quite a common predation method in nature. Can we work out where on the body would they be concentrated? Probably not from the current paper (or very much any published papers on the topic) since as mentioned before none of these animals are complete so how can we talk about concentration when we don't have the whole animal to make comparison. However, as I said before this area is not part of these papers' intention.

"...this supports the idea T. rex hunted hadrosaurs by grabbing the tail.";  that really isn't the point of these papers. All they are saying is that these tail wounds are probably caused by "failed predation acts" deducted from indirect evidence/observations such as the angle of the attack, location of the wound or inference via modern analogs. They have never said that this is the standard or only method/pattern that they used to hunt hadrosaurs as you might have implied here.

"...How about injuries from *successful* attacks?..."; I'm not sure whether this would really add that much value to the discussion because I think that people could argue either ways on this since if this is a "successful attack" then the animal died and no bone remodeling. Did the bite occur after the attack (as in feeding on a carcass) or did the bite happens during an attack (as in a predation act)? We haven't had a reliable method of determining the exact time yet so unless we have a method to work out the timing of these injuries I don't think presenting samples (I'm not sure how many since I haven't read up on these successful attacks) of these successful attacks would change much of the current discussion.

[suspsy]

Modern land carnivores are almost all mammals. Dinosaurs were not mammals that we are aware of so you cannot use the one to suggest the other realistically.

Baloney.

Dinosaurs are compared to modern animals all the time---birds, reptiles, and mammals. How many times has Jack Horner presented the case for T. rex being an obligate scavenger by pointing out that big cats use their front limbs to tackle prey? How many times has that case been countered by pointing out that wolves and hyenas don't use their front limbs to tackle prey? How many times has Triceratops been compared to rhinos and buffalo? How many times have scientists compared sauropod speed against that of elephants?

I did give some rather striking possible alternatives to predation, or at least made a strong of case againstp

You didn't.

I am aware of  the supposed liver in the specimen you linked to . I Also am aware that at this point is contentious and remains debateable .

Really? Point me to an article that contests the presence of biliverdine in the Scipionyx fossil.

My original words were
"Also while it is likely and would seem given, there is NO evidence for liver organs in dinosaurs. There is evidence for tails . "
I am stating evidence...proof, not inference and guesswork.I was asking for proof....proof of livers, proof of predation, proof for any of your comments. None exists. None exists for my own either....and that was the point.

There's nothing debateable about livers existing in dinosaurs. They existed as surely as did hearts, lungs, stomachs, eyes, and brains. There is no possible way for a vertebrate, extinct or extant, to survive without a liver. Ask any scientist. Ask any physician. Ask anyone who's taken high school science. Or elementary school science for that matter.

Not to mention the many existing dinosaur illustrations and models that depict them with *gasp* a liver.

There is a line between defending one's position and denying a simple fact of life science. You have crossed it. You're only hurting your own credibility now.

As for your "joke" I  will take your word for it. Myself I find it somewhat poor form to tell someone you would kill them in a chat forum, where expressions, and context are  often somewhat blurred. I myself at least am not comfortable with it.

Again, nothing more I can do.

[amargasaurus cazaui]

Correct, nothing more you can do, and well stated, thanks.  Threats, inference, and surmise.