Is Tyrannosaurus overrated?

starman

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Jan 2014
4,118
Connecticut
Or it would just bite down onto it's spine from above, like them taking chunks from near the base of hadrosaur tails. I'm sure a T.rex, like any other predator, would grab onto whatever part of it's prey it could, though I wonder if it had a specific kill strategy of trying to bite down from above and sever the spinal cord, the hadrosaur bite marks indicating near misses on a moving target.
I think tail bites indicate tyrannosaurs pursued hadrosaurs, as the latter, lacking weapons, just fled. IMO, tyrannosaurs seldom managed to get close enough to alert hadrosaurs to strike an initial fatal blow, but just bit their tails to stop or slow them, before finishing them.
 

Corvidius

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Jul 2017
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An interesting fact about the Edmontosarus with a bite to it's tail, is that Carpenter found that it probably walked with a limp due to hip problems. I think this shows that the Tyrannosaurus that attacked it was engaged in active stalking and singling out prey, not mindlessly rampaging about and charging at anything it sees, like flashlights in an upturned SUV....
 

starman

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Jan 2014
4,118
Connecticut
An interesting fact about the Edmontosarus with a bite to it's tail, is that Carpenter found that it probably walked with a limp due to hip problems. I think this shows that the Tyrannosaurus that attacked it was engaged in active stalking and singling out prey, not mindlessly rampaging about and charging at anything it sees, like flashlights in an upturned SUV....
Of course Hone wrote that theropods, like a host of modern predators, tended to go after juvenile prey. It makes sense that even Tyrannosaurus went after vulnerable prey.
 

starman

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Jan 2014
4,118
Connecticut
Btw Corvidius, (or everybody) I just posted on Ankylosaurus is my s-visions blog, instead of in DH this time. If you read the post, you’ll see a further indication I don’t consider T. rex overrated. IMO it exerted a profound influence on ankylosaur evolution. :)
 
Mar 2017
878
Colorado
Modern predators:
Generally take the young, old, & infirm. This has been verified many times.
Are only successful 10-20% of the time (this includes changing their minds before committing).
Will scavenge if possible (amount of acceptable decay depends on species).
Most of the predators that operate as individuals (not packs) are ambush predators.

Without using slide rules or calculators, predator minds seemed tuned to avoiding unnecessary risk and for conserving energy as much as possible (if the ambush doesn't work, you might have to chase something down ... or fight).

All of this is pretty much consistent with previous speculation about T.rex behavior.

In the Denver Museum of Nature & Science, there's a room with a reconstructed Triceratops, decaying on a river bank. The paintings on the walls continue the river bank into a deciduous forest ... where a T.rex is lurking. You'd never even notice it if it wasn't pointed out to you.

It's difficult to imagine something that big "sneaking around" but isn't that a little more realistic that all the physics required to chase things?


Entrance to DMNS
 
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Corvidius

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Jul 2017
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It needs to be explained that if T.rex was only a scavenger, then why was it so big, why did it have huge eyes with stereoscopic vision with an overlap the same as a living hawk. Why are there T.rex bite marks on hadrosaur tails, one still with a shed tooth in situ, and the wounds healed. There is physical evidence to show that T.rex actively hunted, and certainly, like all hunters, would also scavenge when the opportunity arose, but no evidence to say it only scavenged. Eyes like a hawk to scavenge?

The real debate is about if T.rex was a pack hunter or not. I think it may have been. One reason is that the T.rex brain was much bigger than it needed to be, and so was that of hadrosaurs living at the same time as T.rex. I think that T.rex had a "big" brain in order to use more advanced hunting techniques than the old outdated tetanuran theropods and, that while some of it's prey, like sauropods, got big, and others evolved armour and weapons, hadrosaurs, with neither giant size or any weapons or armour, used speed and greater intelligence than their ancestors to evade T.rex. Enter speedy juvenile T.rex to flush out the young, old and sick into the jaws of the adults waiting in ambush.
 

Scaeva

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Oct 2012
5,630
Some have suggested that Rex was more of a scavenger than a hunter.
The T-Rex was a scavenger argument is pretty much dead.

As most anyone who went through the "dinosaur phase" in childhood already guessed Tyrannosaurus rex was a fearsome predator.

A plant-eating dinosaur found with a Tyrannosaurus rex tooth lodged in its the tail of a plant-eating dinosaur has confirmed what scientists long suspected: T. rex was a predator.

The tooth was discovered in the tail of a hadrosaur that lived about 66 million years ago.


"It's the Holy Grail for a paleontologist," said study co-author David Burnham, a paleontologist at the University of Kansas. "Not only was the tooth broken off, but the tail had healed around it. That means that Tyrannosaurus rex attacked that other dinosaur."

The findings were published today (July 15) in the journal Proceedings of the National Academy of Sciences.
It's Official: T. Rex Was Ferocious Predator, Not Scavenger

Of course like any apex predator it was probably highly opportunistic and would not pass up a found carcass or an easy steal from a smaller predator. Lions, bears, and wolves do the same.
 
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Mar 2017
878
Colorado
The real debate is about if T.rex was a pack hunter or not. I think it may have been. One reason is that the T.rex brain was much bigger than it needed to be, and so was that of hadrosaurs living at the same time as T.rex. I think that T.rex had a "big" brain in order to use more advanced hunting techniques than the old outdated tetanuran theropods and, that while some of it's prey, like sauropods, got big, and others evolved armour and weapons, hadrosaurs, with neither giant size or any weapons or armour, used speed and greater intelligence than their ancestors to evade T.rex. Enter speedy juvenile T.rex to flush out the young, old and sick into the jaws of the adults waiting in ambush.
It's interesting to consider what evidence you would need to prove this.

T.rex & hadrosaurs have bigger brains than they needed. Predator & prey evolve together: it's why predators have a very hard time taking healthy adult prey which are evolved to defeat them somehow. It's a very pragmatic arms race.

Maiasaurs were found in the context of their nests, leading to the interpretation of parental care. I heard that oviraptors might have been mistakenly identified as egg stealers ... of their own eggs.

Suppose T.rex did hunt exactly as you speculate: small frisky ones flushing & herding prey into the big ones. What would we have to find? Indications of mixed size packs, maybe? A trackway with T.rex prints of various sizes? A bone bed with mixed size individuals caught in a mudslide or something?

Just like that tooth healed into a hadrosaur tail, I think any indication of mixed size individuals would be the smoking gun for pack behavior. I just can't imagine a situation where you'd find mixed sized bones, unless they all chased something off a cliff ... or got caught in some pit. Something like trackways is probably most likely.

Seems like T.rex tracks are pretty rare. There's three individuals here, but it doesn't prove or disprove your theory:
https://www.popularmechanics.com/science/animals/a10933/tyrannosaurus-trackways-reveal-a-dinosaurs-walk-17016027/
"The prints were apparently all made at about the same time. This suggests they were left by tyrannosaurs walking alongside each other. "This is the strongest evidence we can have of gregarious behavior among tyrannosaurs,""

--- I didn't find the website until after my flow-of-consciousness typing.

I SCUBA dived in the Red Sea once. I saw a school of over 200 6' barracuda and wondered "what the Hell do they eat ... that there's an advantage to that huge school?"

So now, we know there were three T.rex's, about 30 yrs old, just out for a stroll. Prey aren't stupid: they LOOK for trouble. They wouldn't see those things coming? Maybe instead of stomping and shaking the ground, they were light on their feet? That same website talks about how they placed their feet in an odd pattern (actually, cat prints, all four feet, are in a line right in front of each other). Uhhhhh .... three enormous predators "sneaking" around together? Maybe they hunted in small groups of adults?
 
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Corvidius

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Jul 2017
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Crows nest
As regards the relationship between tyrannosaurs and hadrosaurs, and leaving sauropods out of the equation at this time, I think that tyrannosaur evolution drove hadrosaur evolution as regards their brain size. The advent of coelurosauria and the evolution of tyrannosaurs from the basal coelurosaur coincides with the timeline of hadrosaurs evolving from iguanadonts. It may be just a coincidence, but I cannot see any reason for the otherwise defenceless hadrosaurs to need to get smart other than advanced social behaviour, including anti predator strategies, as the new model theropods had become more formidable. Other ornithischians had smaller brains, often considerably smaller, but were either armoured, had weapons, or could probably easily outrun at least an adult T.rex, and I'm thinking here of an animal like the pachycephalosaurs. Any theropods preyed on by T.rex generally had good sized brains and could outrun T.rex, no matter from which age group. I doubt T.rex preyed on ornithomimosaurs as JP showed, even if they were a little behind T.rex in brains, but still way ahead of even the brainiest hadrosaur.

I think evidence for T.rex hunting strategies will probably remain conjectural for the most part. Of course an extensive trackway showing juvenile T.rex prints following a herd of hadrosaurs, then following one, then the victim and adult T.rex prints around the remains, could show up one day, but I'm not holding my breath. Even if we found a scene with T.rex and an Edmontosaurus similar to the one with a Tenontosaurus and several Deinonychus remains, it will always remain open to interpretation, though I don't doubt that Deinonychus was a pack hunter.

The hadrosaurs with T.rex bites to their tails had been attacked from behind, so were being chased. One shows some bone pathology indicating potential lameness, though it is impossible to tell if it was lame at the time of the attack or had become so at a later time. I think it reasonable to assume it was singled out for attack as it was already lame, even to only a small degree as predators are good at spotting the smallest weakness.

The idea that juveniles assisted with hunting comes from Philip Currie, who is the front runner with this. I think it is a possibility, but I also think it may ultimately be impossible to prove. What we need to do is find what a Juvenile T.rex hunted and ate. I don't doubt they were altricial and had parental care, but for how long? While dinosaur growth rates are high, T.rex grew at the same rate we do so I'm not sure at what age it could hunt for itself given that various deinonychosaurs, all smarter and faster, would have been a threat to them. Unfortunately the recent otherwise excellent BBC documentary about T.rex, showed a good reconstruction of a juvenile T.rex, but that was it, no weight and speed estimates or that of bite force. Difficult to believe that while they carefully examined the adult that they had no interest in the capabilities of a juvenile, so where is their research?

Anyway, I think that a very young T.rex would have had perhaps too much competition from the more numerous deinonychosaurs, dpending of course on exactly what species and in what numbers were sharing the same ecology as T.rex. While we only have one Dakotaraptor, surely a serious competitor to juvenile T.rex, and deadly to any between chick and about ten years, I think they can be discounted as a temporary visitor to the T.rex range, perhaps, as Starman has posited, at a time when T.rex numbers had temporarily fallen, or they were absent for some reason.

I'm writing all this from the top of my head and a bit tired and probably rambling somewhat, so I'll end with a thought about how T.rex may have placed it's feet. I don't buy the image of a ground shaking stomping T.rex and think that they were probably light on their feet, even at six tons. African bull elephants don't shake the ground unless they want too. A stomping T.rex will wear it's knees and hips out, and I cannot think of any animal that stomps as part of it's normal locomotion. The shaking water in the cup in JP was, IMO, pure fiction.

Hm, groups of hunting adults. I don't see them in a pride like lions, and if they were pack hunters then I think more, in line with their bird relatives, a family group with mom, dad and the kids, and likely from several generations until the older ones broke away. Modern raptors do not give us a model for non avian theropods as they are almost entirely solitary hunters, even when they have a mate. On the other hand, corvids do give a potential model, as while not classed as raptors, ravens hunt, and they, like crows and rooks, have "helpers" from previous generations of their own young until they find their own lives. While the difference in intellect between a raven and a T.rex is truly immense, and I don't mean to compare them like that, T.rex had more than enough brains to form social groups. Hadrosaurs, with far smaller brains lived in herds, cared for their young and, judging from the crests of some, engaged in social behaviour as advanced as any herd of modern cows, and maybe even more so depending on exactly how they used those airhorns on their heads. So it does not require the brains of an Einstein to live together and cooperate.