Triceratops is a baby Torosaurus?

[Alyrium Denryle]

But would there be enough seaside beach corpses to sustain those island Allosauruses, though? I find it odd that they couldn't prey on other creatures on their island. If that island is big enough to support them, then certainly it's big enough to support some eatable herbivores. Like how komodo dragons have water buffalo to eats.

A case like komodo dragons is actually comparatively rare, and the islands in this case were surrounded by marine reptiles, moreover, shallow seas like that are fairly plentiful when it comes to beach washed food. Komodos actually tend to go beach combing at low tide.

[Akhlut]

Just a bit of a nitpick, but from what I've heard, hyenas are actually competent hunters and live more on their own hunts than on scavenging.

When you specify spotted hyenas, yes.

There are however other species.

D'oh! Should have specified. >.<

I don't know about anyone else, but I'm not disputing that T. rexes scavenged; however, due to their size and their only locomotion being simply walking around, I imagine that they would hunt on a relatively frequent basis unless there were plenty of other predators in their territories that could bring down large enough prey to make scavenging a worthwhile lifestyle, as it is for lions and vultures.

Raptors. I am telling you... Imagine a big solitary male lion. They do the same thing to Hyenas, Cheetah, Leopard etc that a scavenger T Rex would have done. Barge in on a kill and use their superior size to intimidate other predators off of their kills.

I suppose at this point I'm mostly quibbling over relative amounts of hunting vs. kleptoparasitism. I imagine that, like modern lions and spotted hyenas, the relative amounts of each varied tremendously by location and local ecosystems. In an area with a paucity of raptors but the presence of large amounts of slow-moving Edmontonsaurs, T. rexes would hunt more often than not, while in areas with lots of raptors and ceratopsians, it would be a lifestyle of stealing from raptors.

[Ritterin Sophia]

Raptors. I am telling you... Imagine a big solitary male lion. They do the same thing to Hyenas, Cheetah, Leopard etc that a scavenger T Rex would have done. Barge in on a kill and use their superior size to intimidate other predators off of their kills.

Except, aren't most Tyrannosaur skeletons found in groups of numerous adults and a number of juveniles? Sue for example. This would mean it's not a solitary animal and a terrestrial scavenger would not have need for the kind of eyesight they are accredited according to modern paleontology.

[Alyrium Denryle]

Raptors. I am telling you... Imagine a big solitary male lion. They do the same thing to Hyenas, Cheetah, Leopard etc that a scavenger T Rex would have done. Barge in on a kill and use their superior size to intimidate other predators off of their kills.

Except, aren't most Tyrannosaur skeletons found in groups of numerous adults and a number of juveniles? Sue for example. This would mean it's not a solitary animal and a terrestrial scavenger would not have need for the kind of eyesight they are accredited according to modern paleontology.

Even vultures have amazing eyesight. Smell only gets you in the vicinity of a kill, after that scavengers like vultures hunt with their eyes.

[Akhlut]

Raptors. I am telling you... Imagine a big solitary male lion. They do the same thing to Hyenas, Cheetah, Leopard etc that a scavenger T Rex would have done. Barge in on a kill and use their superior size to intimidate other predators off of their kills.

Except, aren't most Tyrannosaur skeletons found in groups of numerous adults and a number of juveniles? Sue for example. This would mean it's not a solitary animal and a terrestrial scavenger would not have need for the kind of eyesight they are accredited according to modern paleontology.

Aly said that, not me, by the by.

Anyway, that's a bit of a non sequitor; T. rex evolved from much smaller, much quicker animals that had already evolved great binocular vision, and their descendents had no need to evolve anything different. So, even if T. rexes were entirely scavengers and did not kill their own prey, ever, they had no reason to lose binocular vision, both because it was still reasonably useful for their lifestyle (flying scavengers almost certainly abounded in the late Cretaceous, so the ability to see where they were and how far away they were would have been useful to track a kill even if the wind is blowing away from the T. rex, thus preventing it from tracking carrion by smell), and would not be selected against (what the hell would hunt a T. rex and select for wide-angle vision like herbivorous dinosaurs?).

Remember: just because a trait exists does not necessarily mean it was actively selected for in a particular species. Giant pandas are almost entirely herbivorous, but they retain binocular vision, for instance.

Even vultures have amazing eyesight. Smell only gets you in the vicinity of a kill, after that scavengers like vultures hunt with their eyes.

To be fair, most birds have great eyesight, due to the demands of flight. I imagine poor eyesight would have been selected against due to flying into trees, mistiming landings, and the like.

[Alyrium Denryle]

Remember: just because a trait exists does not necessarily mean it was actively selected for in a particular species. Giant pandas are almost entirely herbivorous, but they retain binocular vision, for instance.

This is a very good point I would like to emphasize. There are many many traits like this. You can use a building analogy. So you have certain pillars that hold up your structure, you can visualize these as the actual adaptations needed to survive in a given environment. Those pillars form arch ways and in the space between the arch and the cieling there are spandrels. Empty spaces that you can fill with... stuff. Paintings, wood cuts, whatever. They serve no function, but are there anyway. A lot of animal traits are like this, the results of neutral evolution and arbitrary shit that is there because nothing else is. Now like any building, animals have also undergone some remodeling, but evolution being what it is, this remodeling was sloppy so you also have archways, spandrels and all, which are no longer load bearing.

[Shroom Man 777]

How popular is the notion of T-rex as scavenger anyway?

Also. Won't all the arguments of T-rex being a scavenger apply to other large therapods in the same size class?

[Elfdart]

I point out that carnivores have to hunt for most of their food and you come back with this (by the way, when you subtracted 68% from 100%, you ended up with 34%?)?

I am sure you will forgive the typo, should be 32. Considering that spotted hyenas have driven the social evolution of most other carnivores in the region, yeah. They may not be specialists, but they do in fact make their living from scavenging, without that 32% they would die.

Then explain how the spotted hyenas from Ngorongoro are able to make almost all their own kills (93%). They don't need the extra 25%.

Insects are animals, fucktard -so finding and eating them counts as predation. Congratulations on finding one medium-to-large animal that gets most of its food by scavenging: the brown hyena, an animal that is (a) an omnivore, eating fruit, eggs and garbage along with carrion and small animals and (b) rare and confined mostly to areas where other predators are rare or non-existent.

Yes, it does. However you are sitting there bitching about what? That a T rex would not be able to find enough to scavenge or engage in my new favorite word-kleptoparasitism? You want this based on comparisons to modern vertebrates.

Why not? Large warm-blooded land animals take on the same roles: herbivore, omnivore, predator, apex predator. It doesn't matter what branch of the family tree their ancestors came from.

As for the brown Hyena, I did exactly as you requested.

No, you lying fucktard. Here is what you claimed:

Bakker may be a carnival barker, but he has never been so harebrained as to suggest that large species of land animal can survive exclusively or mostly by scavenging.

Many large terrestrial carnivores do exactly that, moron

You produced ONE that is rare and more of an omnivore than a predator. So where are all the others?

Thou Shalt Not Shift Thine Goal Posts.

The only person shifting goalposts is you. Why don't you do everyone a favor and shift them right up your ass?

Second, the fact that a predator might look for easy meals at the beach doesn't mean it's more of a scavenger than a hunter.

Have you ever wondered why large predators on small islands are rare? It is because there is no food, dipshit. Even reticulated pythons on small islands have a hard enough time that they had to evolve dwarfism. How do you think a megalosaurid on a small island would do? I will give you a hint. It will become 5-7 meters long and be a scavenger. Dinosaurs large enough to provide a good meal are rare in that particular strata. What is the most abundant food source? Carrion from marine reptiles, stranded turtles and the odd pterosaur.

That 5-7 meter megalosaur would have weighed around half a ton. How many half-ton land predators get all or most of their meat just by eating what conveniently washes up on shore? Do polar bears live that way? No, they hunt for most of their food. Do brown bears? No, they're omnivores and have to hunt for most of their meat, too. What about Siberian tigers (not really half a ton, but the next largest land predator)? No, they hunt for their meals, too.

Also, comparing walking with dinosaurs to the flintstones. Wow. I thought your intellectual dishonesty had reached its bounds.

If you want to get your information about prehistoric animals from bad TV shows, that's your problem. At least The Flintstones was entertaining.

What's really funny is that you would cite the series as a credible source for the idea that tyrannosaurs were mostly scavengers when the series shows scenes like this one:

I used it as a reference for the species, only. The location of the fossil, marine strata near Oxford, the geology of the time period, and its size indicating dwarfism

From the Walking with Dinosaurs site:

The single skeleton is of an animal about 5 metres long. This is fairly small for a theropod. However vertebrae of this specimen looked as if they had not finished growing so this individual was probably not fully grown, and just how big this animal got is not certainly known.

For comparison, Ceratosaurus nasicornis is "only" 6 meters long. This isn't as big as the allosaurs (some of which were almost twice as long and more massive), but it's still a large predator and as the show's own site points out, wasn't full grown.

are all I really need to be able to say what it more than likely is-which frankly is all any paleontologist ever has unless they find wound markings or one specimen inside another (which has happened, though with live birth in Ichthyosaurs). An opportunistic carnivore that got most of its food washed up on the beaches of small islands is all it could actually be. Unless someone finds little Dwarf Sauropods or something.

Or a small species of ornithiscian like Collovosaurus.

You will provide evidence that water buffalo actively hunt down lion cubs, right?

Yep. Including footage.

http://www.metacafe.com/watch/448983/bu ... ack_lions/

Stumbling across cubs and taking the opportunity to trample them is not the same as hunting them down. Even the narrator of the clip says:

The buffalo sense their advantage and defense switches to attack.

You lying fuckhead.

Mockery is not a substitute for evidence on this board. Considering the gravity of falsifying data in the scientific community, you sure as fuck better have justification. If you would like the paper, I can send it to you.

Through his public statements, Horner has shown himself time and again to be a bullshitter. When presented with evidence that contradicts his crank theory, he ignores it. This alone should make anything else he claims suspect -even if he does manage to get it published.

Horner has a very very good reputation among paleontologists for a reason.

He's well-regarded for his work in finding the nests of baby duckbills. On the subject or tyrannosaurs he's a know-nothing and a bullshitter.

No wonder you're such a fanboy.

[Elfdart]

Except, aren't most Tyrannosaur skeletons found in groups of numerous adults and a number of juveniles? Sue for example. This would mean it's not a solitary animal and a terrestrial scavenger would not have need for the kind of eyesight they are accredited according to modern paleontology.

You're thinking of the Albertosaurs found by Philip Currie. It's a much smaller and more lightly built relative, but close enough.

[Elfdart]

How popular is the notion of T-rex as scavenger anyway?

Also. Won't all the arguments of T-rex being a scavenger apply to other large therapods in the same size class?

It began when Laurence Lambe dug up Gorgosaurus (a relative of T.rex) almost a hundred years ago. He didn't think the teeth looked very worn, so he concluded the animal lived on rotting meat. In fact, many of the teeth were worn and in any event, they were constantly being replaced (tyrannosaurs broke quite a few teeth) with new teeth. It's a brain bug.

The notion of T. rex as scavenger has a rather large hole in it: If the animal was too slow and clumsy to catch its own meals, then it would have been too slow and clumsy to compete with other predators for carrion. Leave aside the birds and pterosaurs of the late Cretaceous. There were several dromaeosaurs, Nanotyrannus and a late-model albertosaur -all of which could would have a better chance to reach dead animals and start wolfing down the meat long before the plodding Horner version of T.rex could waddle onto the scene and bully them into letting him have it.

The attributes that make for a lousy predator also make for a lousy scavenger or hijacker.

[Alyrium Denryle]

Then explain how the spotted hyenas from Ngorongoro are able to make almost all their own kills (93%). They don't need the extra 25%.

Because the environment is different there fuckwad. Very simple. Predation strategies, energy budgets etc are all dependent on local environment. I assumed you would know that, but like a six year old it seems I have to use monosyllabic words inscribes into series of wooden blocks for you.

Why not? Large warm-blooded land animals take on the same roles: herbivore, omnivore, predator, apex predator. It doesn't matter what branch of the family tree their ancestors came from.

Why not? Large warm-blooded land animals take on the same roles: herbivore, omnivore, predator, apex predator. It doesn't matter what branch of the family tree their ancestors came from.

Yes. It does. Evolution does not occur in a vacuum. It is not purpose driven, or unconstrained by past variation. An animal filling a particular niche is constrained in how it does that by past evolutionary history. It most certainly matters what branch of the family tree they come from. if you think you can talk to me about the evolution of predation and constraints on evolution, you are sadly mistaken. Would you like me to provide you with my reference library on these topics?

You produced ONE that is rare and more of an omnivore than a predator. So where are all the others?

First off, omnivory is irrelevant. Outside of africa, most mammalian predators are actually omnivores, including most canines.

Also: define large. Strictly speaking a raccoon when compared to almost everything else is huge by comparison, and african/asian megafauna apex predators are really the exception to the rule. I will restrict myself to things in the Meso category or larger. I also will not limit myself to mammals, but instead go by relative size within a given taxonomic group. Starting with Reptiles:

Komodo Dragons-They get most of their food from various forms of carrion, including appropriation of the kills of others, and beach combing.

Other Monitor Lizards-There are populations of Water Monitor in SE asia that specialize in scavenging human refuse.

Certain species of crocodile-Nile crocodiles for example also get a significant portion of their food from scavenging when they are adults. This is because the events that allow them to actually hunt for large prey happen twice a year-less in some places. Dead hippos and theft of other species kills at the waters edge make up a significant diet percentage. Again, depending on local conditions.

Mugger crocodiles, to the extent they exist outside of parks anymore, used to get a significant portion (probably most, it is poorly documented because it was india) of their meals from the corpses of people set out into the various holy rivers within their range.

Common Snapping Turtles-get much of their food in the wild scavenging. Turtles are in general under-appreciated in this regard.

Some of these are properly considered semi-aquatic of course.

Birds-Most corvids and vultures, which are large in comparison to other flying birds.

Mammals-Opposums, Raccoons (these guys are really opportunistic... depending on where they are, they eat everything), Tasmanian devils, Brown Hyena, if other large predators present coyotes also get much of their food from scavenging.

That 5-7 meter megalosaur would have weighed around half a ton. How many half-ton land predators get all or most of their meat just by eating what conveniently washes up on shore?

You also have a scaling problem. There are very few things living now that will regularly wash up on a beach that are of sufficient size to power the metabolism of a half ton endotherm. Those things were common back then, particularly in the shallow sea that was most of europe at that time. The population sizes of these 5-7 meter metalosaurids (family name, not genus), would also not have been very large. What exactly were they preying upon if not carrion? It is not as if terrestrial prey was common.

For comparison, Ceratosaurus nasicornis is "only" 6 meters long. This isn't as big as the allosaurs (some of which were almost twice as long and more massive), but it's still a large predator and as the show's own site points out, wasn't full grown.

Allosaurus proper has been found to reach lengths of 12 meters.

Frankly, it all depends on their dietary specialization and what environment they lived in. You also have to consider size relative to other species. Take megalosaurus for example. Adult specimens would reach lengths of 9 meters. As for our little partially grown friend, the juvenile found was less than 5 meters. 7 meters is one projection for adult size.

Or a small species of ornithiscian like Collovosaurus.

And the question is whether or not they existed in sufficient number to support viable populations of an apex predator. This may also depend on where and in what time period we are talking about. Large islands may well have supported them as predators. Smaller islands get small populations as scavengers. Again, environmental context matters. The only known specimen was a sub-adult in a marine deposit.

It would be nice if you had actual distribution data for that species. The reference they list is a site called Dinoruss. A bit dubious. Where afterall are they getting their information regarding Eustreptospondylus as a predator on this particular species?

Stumbling across cubs and taking the opportunity to trample them is not the same as hunting them down. Even the narrator of the clip says:

The buffalo sense their advantage and defense switches to attack.

You lying fuckhead.

Sometimes Water Buffalo will go searching for lion cubs to kill, or will stumble on hidden cubs and very deliberately crush them to death. But of course Elfdart does not know about it, so it must not ever happen

That was my specific claim. You will notice the Or. Indicating that either may occur.

You wonder why they do that? How it is exactly that they got it in their heads to actively go after lion cubs when they stumble upon a pride? Has it not occurred to you that this might be something that happens regularly? Whether they seek out and kill, or stumble upon and kill is irrelevant to the question of whether or not it is a viable explanation for healed bite marks on a ceratopsian (tail if I remember properly) vertebrae.

Through his public statements, Horner has shown himself time and again to be a bullshitter. When presented with evidence that contradicts his crank theory, he ignores it. This alone should make anything else he claims suspect -even if he does manage to get it published.

Such as? Will you give a list of occurrences with references? I have repeatedly asked you for various forms of evidence in this thread. Requests which you have pointedly ignored.

He's well-regarded for his work in finding the nests of baby duckbills. On the subject or tyrannosaurs he's a know-nothing and a bullshitter.

No wonder you're such a fanboy.

Really? Would you like a list of his recent publications? I will highlight the ones on T Rex and Ceratopsians

Horner, J.R., Goodwin, M. 2008. Ontogeny of cranial epi-ossifications in Triceratops. Journal of Vertebrate Paleontology 28(1):134-144.

Chinnery, B., Horner, J.R. 2007. A new neoceratopsian dinosaur linking North American and Asian taxa. Jornal of Vertebrate Paleontology 27(3):625-641.

Horner, J.R., Goodwin, M. 2006. Major cranial changes in Triceratops. Proceedings of the Royal Society (B):273:2757-2761.

Horner, J. R, Padian, K, and Ricqles, A. de. 2005. How dinosaurs grew so large and so small. Scientific American 293(4):32-39.

Schweitzer, M. H., J. L. Wittmeyer, J. R. Horner, and J. B. Toporski. 2005. Soft-tissue vessels and cellular preservation in Tyrannosaurus rex. Science 307:1952-1955.

Schweitzer, M. H., Wittmeyer, J. L., and Horner, J. R. 2005. Gender-specific reproductive tissue in ratites and Tyrannosaurus rex. Science 308:1456-1460.

Main, R.P., Ricqles, A. de, Horner, J.R., and Padian, K. 2005. The evolution and function of thyreophoran dinosaur scutes: implications for plate function in stegosaurs. Paleobiology 31(2):291-314.

Horner, J.R., Padian, K. 2004. Age and growth dynamics of Tyrannosaurus rex. Proceedings Royal Society (B) 271 (1551):1875-1880.

Goodwin, M. and Horner, J. R. 2004. Cranial histology of pachycephalosaurs (Ornithischia: Marginocephalia) reveals transitory structures inconsistent with head-butting behavior. Paleobiology 30(2):253-276.

Ricqlès, A. de, K. Padian, J. R. Horner. 2003. On the histology of some Triassic pseudosuchian archosaurs and related taxa. Annales de Paléontologie 89:67-101.

Ricqlès, A. de, K. Padian, J. R. Horner, E. Lamm, N. Myhrvold. 2003. Osteohistology of Confuciousornis anctus (Theropoda: Aves). Journal of Vertebrate Paleontology 23(2):373-386.

Horner, J. 2002. Evidence of dinosaur social behavior. Chapter 9, pp 71-78 in Dinosaurs, The Science behind the Stories, American Geological Institute, Alexandria, Virginia.

Padian, K. and Horner, J. R. 2002. Typology versus transformation in the origin of birds. Trends in Ecology and Evolution 17(3):120-124.

Horner, J. R., Padian, K., and Ricqlès, A. de 2001. Comparative osteohistology of some embryonic and perinatal archosaurs: developmental and behavioral implications for dinosaurs. Paleobiology 27(1): 39-58.

Padian, K., A. J. de Ricqlès, and J. R. Horner. 2001. Dinosaurian growth rates and bird origins. Nature 412:405-408.

Horner, J. R. 2001. Dinosaur Ethology, pp. 416-419 in Palaeobiology II, edited by Briggs and Crowther (Blackwell Science, Oxford).

Horner, J. R. 2000. Dinosaur reproduction and parenting. Annual Reviews of Earth and Planetary Sciences 28:19-45.

Horner, J. R., Ricqlès, A. de, and Padian, K. 2000. Long bone histology of the hadrosaurid Maiasaura peeblesorum: growth dynamics and physiology based on an ontogenetic series of skeletal elements. Journal of Vertebrate Paleontology 20(1):109-123.

Horner, J. R., Ricqlès, A. de, and Padian, K. 1999. Variation in dinosaur skeletochronology indicators: implications for age assessment and physiology. Paleobiology 19(4):295-304.

The format here changes because they are from a search rather than the selected publications on his CV, I am also ONLY including the relevant Ceratopsian and Rex papers.

Common Avian Infection Plagued the Tyrant Dinosaurs
Author(s): Wolff EDS (Wolff, Ewan D. S.), Salisbury SW (Salisbury, Steven W.), Horner JR (Horner, John R.), Varricchio DJ (Varricchio, David J.)
Source: PLOS ONE Volume: 4 Issue: 9 Article Number: e7288 Published: SEP 30 2009

Cranial design and function in a large theropod dinosaur
Author(s): Rayfield, EJ; Norman, DB; Horner, CC, et al.
Source: NATURE Volume: 409 Issue: 6823 Pages: 1033-1037 Published: FEB 22 2001


Preservation of biomolecules in cancellous bone of Tyrannosaurus rex
Author(s): Schweitzer, MH; Johnson, C; Zocco, TG, et al.
Source: JOURNAL OF VERTEBRATE PALEONTOLOGY Volume: 17 Issue: 2 Pages: 349-359 Published: JUN 1997



I will take him over your google doctorate any day of the fucking week.

[Ritterin Sophia]

Seriously though, could someone explain to me what a terrestrial scavenger would need binocular vision in excess of a modern hawk's for that natural selection would give it?

[Alyrium Denryle]

Seriously though, could someone explain to me what a terrestrial scavenger would need binocular vision in excess of a modern hawk's for that natural selection would give it?

Tyranosaurs evolved from small visually oriented predators. They are closely related or even sister to dromeosaurs if I remember properly (dont quote me, dont have a phylogeny in front of me). It is a holdover. Also, as I said, a scent only gets you in the general direction of a corpse.

Honestly, I dont actually think they were strictly scavengers. Only that the case is convincing enough to warrant discussion (as opposed to Google Doctor Elfdart writing off a well respected paleontologist as a bullshit artist). Personally, I think they did the long-distance heard following, either solitary or in groups that I mentioned earlier. Their anatomy seems better for that.

[Akhlut]

Seriously though, could someone explain to me what a terrestrial scavenger would need binocular vision in excess of a modern hawk's for that natural selection would give it?

Remember: just because a trait exists does not necessarily mean it was actively selected for in a particular species. Giant pandas are almost entirely herbivorous, but they retain binocular vision, for instance.

Why do giant pandas, who eat almost nothing but plant material, have great binocular vision? Because they descended from animals that had great binocular vision. Plus, it would have been useful for tracking aerial scavengers or just following herds to quickly snipe up any sick animals, trampled juveniles, or kills from other predators. Further, because it needs eyes and some sort of skull conformation anyway, it doesn't waste any more energy in developing the skull and eyes into a strongly binocular conformation early in development than it would in any other conformation. So, basically, it reduces down to it still being a useful trait and it doesn't cost the T. rex anything more energy to develop binocular vision as it would any other type of vision.

[Shroom Man 777]

You know, I wonder how the hell those Rex bones managed to preserve those soft tissues inside them. I wonder if the creationists are jumping around in joy over this.

[Anguirus]

Tyranosaurs evolved from small visually oriented predators. They are closely related or even sister to dromeosaurs if I remember properly (dont quote me, dont have a phylogeny in front of me). It is a holdover. Also, as I said, a scent only gets you in the general direction of a corpse.

I believe that tyrannosaurids are sister to all other coelurosaur groups (including the ornithomimids, "raptors," and what we consider to be true birds). However, I'm not on campus (so I don't have access to many actual papers) so my only memory-refreshment is coming from Google.

In any case, most (all?) theropods had binocular vision, with coelurosaurs having better binocular vision. This goes back to evolutionary constraints...arguing that binocular vision is an adaptation for Tyrannosaurus in particular to hunt (or do anything else) is entirely false.

[Elfdart]

Why not? Large warm-blooded land animals take on the same roles: herbivore, omnivore, predator, apex predator. It doesn't matter what branch of the family tree their ancestors came from.

Yes. It does. Evolution does not occur in a vacuum. It is not purpose driven, or unconstrained by past variation. An animal filling a particular niche is constrained in how it does that by past evolutionary history.

That does not change the fact that given time, animals do evolve to take advantage of openings in the eco-system. That's why some kangaroos and ungulates evolved sharp teeth and started eating meat. It's why the panda, a member of the Carnivora, evolved to live off bamboo shoots.

It most certainly matters what branch of the family tree they come from.

See above.

if you think you can talk to me about the evolution of predation and constraints on evolution, you are sadly mistaken.

That's due to your dishonesty. It's nothing to boast about.


For example:

You produced ONE that is rare and more of an omnivore than a predator. So where are all the others?

First off, omnivory is irrelevant. Outside of africa, most mammalian predators are actually omnivores, including most canines.

Also: define large. Strictly speaking a raccoon when compared to almost everything else is huge by comparison,

When all else fails, try to change the terms: in this case the meaning of the word large. Large meat-eaters would be the largest ones in a particular ecosystem and no, man-made ones don't count. My neighbor's cat might be the king of his jungle backyard, but that's not remotely comparable to the large ecosystems with large land predators such as the Ngorongoro Crater, the Serengeti, Yellowstone, Denali or any number of others featuring large land herbivores and the land animals who prey on them. The raccoon or house cat or spider or praying mantis is not remotely comparable to the prehistoric ecosystems of the Late Cretaceous (Lance, Hell Creek, Judith River, Nemegt), or the Morrison in the Jurassic or even southern California during the Pleistocene. In all of these environments, there is at least one dominant predator and many have more than one major predator. Creatures like the brown hyena are rare oddities consigned to peripheral habitats.

Now, were tyrannosaurs (including close relatives like tarbosaurus, nanotyrannus, daspletosaurus, gorgosaurus, albertosaurus et al) rare animals that eked out a living in marginal habitats? No, they were not only the largest, but the most common large predators in their ecosystems:

White rhino-sized Albertosaurus was the dominant predator of the Judith River, making up about 75 percent of the big-predator fauna.

With the possible exception of the rare and possibly herbivorous Deinocherius, T. bataar had no competitors

As for competition, the smaller, more gracileand rare Albertosaurus megagracilis was about all, and it preferred the duckbills. A. lacensis was too small to be much more than its occasional prey, except when the albertosaur dared pick off a juvenile T. rex from under its parents’ noses!

Yes, large terrestrial meat-eaters whose range included most of North America and Asia, and were the most common large predators in their respective ecosystems are comparable to rare species that live at the fringes.

and african/asian megafauna apex predators are really the exception to the rule.

Really?

If you factor out humans and the effects of civilization, as well as bears and primates (which are omnivores, getting a large percentage of their food in the form of vegetation) you have the following large, warm-blooded terrestrial meat-eaters:

North America: wolf, puma, jaguar
South America: puma, jaguar
Europe: wolf, lion
Middle East: wolf, lion, leopard, tiger, cheetah, striped hyena
Far East: wolf, leopard, ounce, tiger

< dishonest bullfuckery snipped >

I love the way you trot out animals, most of whom are:

Rare
Cold-blooded
Aquatic or semi-aquatic
Dependent on man-made garbage and refuse in modern times

Those are very comparable to large, terrestrial, warm-blooded meat-eaters who didn’t have the benefit of human garbage to sift through for easy meals.

Birds-Most corvids and vultures, which are large in comparison to other flying birds.

Now you’re really clutching at straws. Animals that fly or soar on thermals are able to specialize in eating carrion because gliding burns very few calories, and gliding/flying allows them to find and land on carrion much faster than land animals can. Feel free to show me a tyrannosaur with wings capable of flight and your point might be valid.

Mammals-Opposums, Raccoons (these guys are really opportunistic... depending on where they are, they eat everything), Tasmanian devils, Brown Hyena, if other large predators present coyotes also get much of their food from scavenging.

And what other, larger predators were providing the tyrannosaurs with leftovers?

That 5-7 meter megalosaur would have weighed around half a ton. How many half-ton land predators get all or most of their meat just by eating what conveniently washes up on shore?

You also have a scaling problem. There are very few things living now that will regularly wash up on a beach that are of sufficient size to power the metabolism of a half ton endotherm. Those things were common back then, particularly in the shallow sea that was most of europe at that time. The population sizes of these 5-7 meter metalosaurids (family name, not genus), would also not have been very large. What exactly were they preying upon if not carrion? It is not as if terrestrial prey was common.

Collovosaurus was found in the same part of Mid-Jurassic England as Eustreptospondylus. Each animal is known from one specimen, so going by the fossil record alone, the former was at least as common as the latter.

And the question is whether or not they existed in sufficient number to support viable populations of an apex predator. This may also depend on where and in what time period we are talking about. Large islands may well have supported them as predators. Smaller islands get small populations as scavengers. Again, environmental context matters. The only known specimen was a sub-adult in a marine deposit.

Except Horner isn’t claiming that a few isolated tyrannosaurs may have lived off of what washed up on shore in a few lucky cases where that’s enough for large animals to eat. He claims they were all scavengers and incapable of hunting for reasons that are so laughable that the argument could be made that I’m actually giving him too much credit by calling him a bullshitter.

Stumbling across cubs and taking the opportunity to trample them is not the same as hunting them down. Even the narrator of the clip says:

The buffalo sense their advantage and defense switches to attack.

You lying fuckhead.

Sometimes Water Buffalo will go searching for lion cubs to kill, or will stumble on hidden cubs and very deliberately crush them to death. But of course Elfdart does not know about it, so it must not ever happen

That was my specific claim. You will notice the Or. Indicating that either may occur.

So you concede that there’s no evidence for the first part, right?

You wonder why they do that? How it is exactly that they got it in their heads to actively go after lion cubs when they stumble upon a pride? Has it not occurred to you that this might be something that happens regularly? Whether they seek out and kill, or stumble upon and kill is irrelevant to the question of whether or not it is a viable explanation for healed bite marks on a ceratopsian (tail if I remember properly) vertebrae.

If the animal had a bite wound in the tail, it was attacked from behind. You know, since animals’ tails are located in back. Now, if an animal is bitten by another from behind then either the animal doing the biting was hunting or chasing the bitee, or this ridiculous idea that the hadrosaur stumbled across a tyrannosaur, was startled, turned and ran –being bitten in the process. But if Horner was right, and T. rex was incapable of hunting, why would the duckbill (IIRC Edmontosaurus, an enormous plant-eater with little to fear from smaller, scarcer predators) run away?

Through his public statements, Horner has shown himself time and again to be a bullshitter. When presented with evidence that contradicts his crank theory, he ignores it. This alone should make anything else he claims suspect -even if he does manage to get it published.

Such as? Will you give a list of occurrences with references? I have repeatedly asked you for various forms of evidence in this thread. Requests which you have pointedly ignored.

You were saying?

[Alyrium Denryle]

That does not change the fact that given time, animals do evolve to take advantage of openings in the eco-system. That's why some kangaroos and ungulates evolved sharp teeth and started eating meat. It's why the panda, a member of the Carnivora, evolved to live off bamboo shoots.

And those cases are rare. By your logic "If it is not found in an animal today, it would not have been found in the past" should have decrying the existence of carnivorous ungulates, which to my knowledge are currently extinct.

Still eating meat is actually easier physiologically than eating plants. Most of the energy from plants is in cellulose which is rather hard to digest.

You still have not addressed the point satisfactorily. Why should something that lived 65 million years ago be bound to exactly the same niches we see today? There was some interesting stuff back in prehistory. Flying reptiles, large venomous synapsids. The scale of the megafauna makes one sad that there is no prefix for 1x10^7. There were groups of animals that no longer exist at all like massive marine squamates.

When all else fails, try to change the terms: in this case the meaning of the word large. Large meat-eaters would be the largest ones in a particular ecosystem and no, man-made ones don't count.

The largest available in many ecosystems are all either introduced, omnivores, or belong to a single relatively small lineage. Cats. Why exactly should the evolution of big cats constrain the evolution of a group of animals who last shared a common ancestor with them back in the carboniferous?

The fact of the matter is, you never defined your term, so I defined it for you.

he raccoon or house cat or spider or praying mantis is not remotely comparable to the prehistoric ecosystems of the Late Cretaceous

Neither are any of our extant ecosystems. Let me spell this out. Clements was wrong. Communities of organisms are not teleologically driven toward certain climax communities. There is no evidence that a community in the mesozoic needs to be in any way similar or equivalent to the ones we have today. Your claim that very broad niches were filled means absolutely nothing.

In all of these environments, there is at least one dominant predator and many have more than one major predator. Creatures like the brown hyena are rare oddities consigned to peripheral habitats.

At that size scale, today, sure. I grant that. Most of the scavengers that are not omnivores are much smaller. On the other hand, it is a completely irrelevant red-herring with regard to the Mesozoic, because the animals that existed back then were not under the same evolutionary constraints as the ones which exist today, they were not from the same lineages, and in fact were not even in the same Class.

Now, were tyrannosaurs (including close relatives like tarbosaurus, nanotyrannus, daspletosaurus, gorgosaurus, albertosaurus et al) rare animals that eked out a living in marginal habitats? No, they were not only the largest, but the most common large predators in their ecosystems:

And as I have said, you cannot compare the ecosystems side by side like that. You have no basis upon which to do so.

White rhino-sized Albertosaurus was the dominant predator of the Judith River, making up about 75 percent of the big-predator fauna.

And I am supposed to take the fact claim if a book written for laypersons in the midst of a large debate within the scientific community on the matter as gospel? Really?

If you factor out humans and the effects of civilization, as well as bears and primates (which are omnivores, getting a large percentage of their food in the form of vegetation) you have the following large, warm-blooded terrestrial meat-eaters:

North America: wolf, puma, jaguar
South America: puma, jaguar
Europe: wolf, lion
Middle East: wolf, lion, leopard, tiger, cheetah, striped hyena
Far East: wolf, leopard, ounce, tiger

I was referring to the fact that most predators are far smaller. Megafauna is a rare exception when it comes to predation both now, and in the past. Most predators, endo or ectothermic are far smaller in scale, and are actually more important in terms of the biomass they consume and the communities they structure. They are also more numerous both in species count and in number of individuals. Predation by non-humans actually has a fairly small impact (generally) on the populations of large grazers/browsers whos communities are regulated bottom-up by food supply more than predation (North america is an exception to this, or was because of the particular ecology of north American browsers like deer)

And what other, larger predators were providing the tyrannosaurs with leftovers?

They dont have to be large. Raptors, of the various species extant at the time, were more than capable of bringing down even the largest of extant herbivores. They just did not do so in solitary fashion. They also would not fossilize as readily as something as large as a tyrannosaur.

Collovosaurus was found in the same part of Mid-Jurassic England as Eustreptospondylus. Each animal is known from one specimen, so going by the fossil record alone, the former was at least as common as the latter.

That is a non-sequiter and you know it. Besides, in order to support a predator population, the prey must be many times more abundant than the species that preys upon it. The rule of thumb is ten times the biomass.

Except Horner isn’t claiming that a few isolated tyrannosaurs may have lived off of what washed up on shore in a few lucky cases where that’s enough for large animals to eat. He claims they were all scavengers and incapable of hunting for reasons that are so laughable that the argument could be made that I’m actually giving him too much credit by calling him a bullshitter.

I am sorry, but I will take the guy with a PhD who studies the behavioral ecology of dinosaurs over you, who relies on the dinosaur encyclopedia and who has no grasp of ecology, evolution, or anatomy any day of the week.

So you concede that there’s no evidence for the first part, right?

Sure. Though it does not preclude a similar encounter happening prior to KT.

If the animal had a bite wound in the tail, it was attacked from behind. You know, since animals’ tails are located in back. Now, if an animal is bitten by another from behind then either the animal doing the biting was hunting or chasing the bitee, or this ridiculous idea that the hadrosaur stumbled across a tyrannosaur, was startled, turned and ran –being bitten in the process. But if Horner was right, and T. rex was incapable of hunting, why would the duckbill (IIRC Edmontosaurus, an enormous plant-eater with little to fear from smaller, scarcer predators) run away?

You saw the video, and changed the subject to starling rather than an attack on offspring. Herbivore attempts to trample baby. Mom intercedes, from behind.

As a rule, defensive bites are not as nasty as predatory ones. A T rex had a bite force of an estimated 30 thousand PSI and teeth perfect for fragmenting bone. If it was a predatory bite, there would not have been a vertebrae left to heal.



Post subject: Re: Triceratops is a baby Torosaurus? Reply with quote
Alyrium Denryle wrote:
Quote:
Why not? Large warm-blooded land animals take on the same roles: herbivore, omnivore, predator, apex predator. It doesn't matter what branch of the family tree their ancestors came from.


Yes. It does. Evolution does not occur in a vacuum. It is not purpose driven, or unconstrained by past variation. An animal filling a particular niche is constrained in how it does that by past evolutionary history.


That does not change the fact that given time, animals do evolve to take advantage of openings in the eco-system. That's why some kangaroos and ungulates evolved sharp teeth and started eating meat. It's why the panda, a member of the Carnivora, evolved to live off bamboo shoots.


Quote:
It most certainly matters what branch of the family tree they come from.


See above.


Quote:
if you think you can talk to me about the evolution of predation and constraints on evolution, you are sadly mistaken.


That's due to your dishonesty. It's nothing to boast about.


For example:

Quote:
Quote:
You produced ONE that is rare and more of an omnivore than a predator. So where are all the others?


First off, omnivory is irrelevant. Outside of africa, most mammalian predators are actually omnivores, including most canines.

Also: define large. Strictly speaking a raccoon when compared to almost everything else is huge by comparison,


When all else fails, try to change the terms: in this case the meaning of the word large. Large meat-eaters would be the largest ones in a particular ecosystem and no, man-made ones don't count. My neighbor's cat might be the king of his jungle backyard, but that's not remotely comparable to the large ecosystems with large land predators such as the Ngorongoro Crater, the Serengeti, Yellowstone, Denali or any number of others featuring large land herbivores and the land animals who prey on them. The raccoon or house cat or spider or praying mantis is not remotely comparable to the prehistoric ecosystems of the Late Cretaceous (Lance, Hell Creek, Judith River, Nemegt), or the Morrison in the Jurassic or even southern California during the Pleistocene. In all of these environments, there is at least one dominant predator and many have more than one major predator. Creatures like the brown hyena are rare oddities consigned to peripheral habitats.

Now, were tyrannosaurs (including close relatives like tarbosaurus, nanotyrannus, daspletosaurus, gorgosaurus, albertosaurus et al) rare animals that eked out a living in marginal habitats? No, they were not only the largest, but the most common large predators in their ecosystems:

Gregory Paul, Predatory Dinosaurs of the World wrote:
White rhino-sized Albertosaurus was the dominant predator of the Judith River, making up about 75 percent of the big-predator fauna.


page 343 wrote:
With the possible exception of the rare and possibly herbivorous Deinocherius, T. bataar had no competitors


page 346 wrote:
As for competition, the smaller, more gracileand rare Albertosaurus megagracilis was about all, and it preferred the duckbills. A. lacensis was too small to be much more than its occasional prey, except when the albertosaur dared pick off a juvenile T. rex from under its parents’ noses!


Yes, large terrestrial meat-eaters whose range included most of North America and Asia, and were the most common large predators in their respective ecosystems are comparable to rare species that live at the fringes.


Quote:
and african/asian megafauna apex predators are really the exception to the rule.


Really?

If you factor out humans and the effects of civilization, as well as bears and primates (which are omnivores, getting a large percentage of their food in the form of vegetation) you have the following large, warm-blooded terrestrial meat-eaters:

North America: wolf, puma, jaguar
South America: puma, jaguar
Europe: wolf, lion
Middle East: wolf, lion, leopard, tiger, cheetah, striped hyena
Far East: wolf, leopard, ounce, tiger


Quote:
< dishonest bullfuckery snipped >


I love the way you trot out animals, most of whom are:

Rare
Cold-blooded
Aquatic or semi-aquatic
Dependent on man-made garbage and refuse in modern times

Those are very comparable to large, terrestrial, warm-blooded meat-eaters who didn’t have the benefit of human garbage to sift through for easy meals.


Quote:
Birds-Most corvids and vultures, which are large in comparison to other flying birds.


Now you’re really clutching at straws. Animals that fly or soar on thermals are able to specialize in eating carrion because gliding burns very few calories, and gliding/flying allows them to find and land on carrion much faster than land animals can. Feel free to show me a tyrannosaur with wings capable of flight and your point might be valid.

Quote:
Mammals-Opposums, Raccoons (these guys are really opportunistic... depending on where they are, they eat everything), Tasmanian devils, Brown Hyena, if other large predators present coyotes also get much of their food from scavenging.


And what other, larger predators were providing the tyrannosaurs with leftovers?

Quote:
Quote:
That 5-7 meter megalosaur would have weighed around half a ton. How many half-ton land predators get all or most of their meat just by eating what conveniently washes up on shore?


You also have a scaling problem. There are very few things living now that will regularly wash up on a beach that are of sufficient size to power the metabolism of a half ton endotherm. Those things were common back then, particularly in the shallow sea that was most of europe at that time. The population sizes of these 5-7 meter metalosaurids (family name, not genus), would also not have been very large. What exactly were they preying upon if not carrion? It is not as if terrestrial prey was common.


Collovosaurus was found in the same part of Mid-Jurassic England as Eustreptospondylus. Each animal is known from one specimen, so going by the fossil record alone, the former was at least as common as the latter.




Quote:
And the question is whether or not they existed in sufficient number to support viable populations of an apex predator. This may also depend on where and in what time period we are talking about. Large islands may well have supported them as predators. Smaller islands get small populations as scavengers. Again, environmental context matters. The only known specimen was a sub-adult in a marine deposit.


Except Horner isn’t claiming that a few isolated tyrannosaurs may have lived off of what washed up on shore in a few lucky cases where that’s enough for large animals to eat. He claims they were all scavengers and incapable of hunting for reasons that are so laughable that the argument could be made that I’m actually giving him too much credit by calling him a bullshitter.


Quote:
Quote:
Stumbling across cubs and taking the opportunity to trample them is not the same as hunting them down. Even the narrator of the clip says:

The buffalo sense their advantage and defense switches to attack.

You lying fuckhead.

Quote:
Sometimes Water Buffalo will go searching for lion cubs to kill, or will stumble on hidden cubs and very deliberately crush them to death. But of course Elfdart does not know about it, so it must not ever happen


That was my specific claim. You will notice the Or. Indicating that either may occur.


So you concede that there’s no evidence for the first part, right?


Quote:
You wonder why they do that? How it is exactly that they got it in their heads to actively go after lion cubs when they stumble upon a pride? Has it not occurred to you that this might be something that happens regularly? Whether they seek out and kill, or stumble upon and kill is irrelevant to the question of whether or not it is a viable explanation for healed bite marks on a ceratopsian (tail if I remember properly) vertebrae.


If the animal had a bite wound in the tail, it was attacked from behind. You know, since animals’ tails are located in back. Now, if an animal is bitten by another from behind then either the animal doing the biting was hunting or chasing the bitee, or this ridiculous idea that the hadrosaur stumbled across a tyrannosaur, was startled, turned and ran –being bitten in the process. But if Horner was right, and T. rex was incapable of hunting, why would the duckbill (IIRC Edmontosaurus, an enormous plant-eater with little to fear from smaller, scarcer predators) run away?


Quote:
Quote:
Through his public statements, Horner has shown himself time and again to be a bullshitter. When presented with evidence that contradicts his crank theory, he ignores it. This alone should make anything else he claims suspect -even if he does manage to get it published.


Such as? Will you give a list of occurrences with references? I have repeatedly asked you for various forms of evidence in this thread. Requests which you have pointedly ignored.

You were saying?

Not evidence. There is no reason to think that they presented either of them with the other person's arguments. Moreover, the whole thing was edited together from larger cuts.

Moreover, nothing Curry was saying actually precludes scavenging, if you understand that T Rex evolved from much smaller carnivores.

Binocular Vision: Evolved from a smaller predator, and it would still be helpful in finding a corpse that one has smelled with the massive massive olfactory bulb.

Hearing: Tracking a heard which made low sounds is useful for both a hunter and a scavenger. Think about this for a moment. Unlike a vulture, this animal cannot soar on thermals and find fresh kills. It has to narrow down its searches. Following a specific heard is a good way to do that. Moreover, if T rex made low sounds, say, a mating call, it would be useful to hear this. The hearing could well have been there via sexual selection.

Teeth: Shape--evolved from, smaller predators. The tooth shape would not have needed to change. Rooting--Scavenging, particularly corpses that may have been picked over, also requires large strong serrated teeth.



I note that you completely ignore the citation list.

[ray245]

Alyrium, is it possible to edit your post above? It's a little hard to follow what you are saying in the above post.

[Alyrium Denryle]

Alyrium, is it possible to edit your post above? It's a little hard to follow what you are saying in the above post.

I just noticed the problem, and my time has expired... I can copy the post and its proper formatting though.

[Alyrium Denryle]

That does not change the fact that given time, animals do evolve to take advantage of openings in the eco-system. That's why some kangaroos and ungulates evolved sharp teeth and started eating meat. It's why the panda, a member of the Carnivora, evolved to live off bamboo shoots. [/quote]

And those cases are rare. By your logic "If it is not found in an animal today, it would not have been found in the past" should have decrying the existence of carnivorous ungulates, which to my knowledge are currently extinct.

Still eating meat is actually easier physiologically than eating plants. Most of the energy from plants is in cellulose which is rather hard to digest.

You still have not addressed the point satisfactorily. Why should something that lived 65 million years ago be bound to exactly the same niches we see today? There was some interesting stuff back in prehistory. Flying reptiles, large venomous synapsids. The scale of the megafauna makes one sad that there is no prefix for 1x10^7. There were groups of animals that no longer exist at all like massive marine squamates.

When all else fails, try to change the terms: in this case the meaning of the word large. Large meat-eaters would be the largest ones in a particular ecosystem and no, man-made ones don't count.

The largest available in many ecosystems are all either introduced, omnivores, or belong to a single relatively small lineage. Cats. Why exactly should the evolution of big cats constrain the evolution of a group of animals who last shared a common ancestor with them back in the carboniferous?

The fact of the matter is, you never defined your term, so I defined it for you.

he raccoon or house cat or spider or praying mantis is not remotely comparable to the prehistoric ecosystems of the Late Cretaceous

Neither are any of our extant ecosystems. Let me spell this out. Clements was wrong. Communities of organisms are not teleologically driven toward certain climax communities. There is no evidence that a community in the mesozoic needs to be in any way similar or equivalent to the ones we have today. Your claim that very broad niches were filled means absolutely nothing.

In all of these environments, there is at least one dominant predator and many have more than one major predator. Creatures like the brown hyena are rare oddities consigned to peripheral habitats.

At that size scale, today, sure. I grant that. Most of the scavengers that are not omnivores are much smaller. On the other hand, it is a completely irrelevant red-herring with regard to the Mesozoic, because the animals that existed back then were not under the same evolutionary constraints as the ones which exist today, they were not from the same lineages, and in fact were not even in the same Class.

Now, were tyrannosaurs (including close relatives like tarbosaurus, nanotyrannus, daspletosaurus, gorgosaurus, albertosaurus et al) rare animals that eked out a living in marginal habitats? No, they were not only the largest, but the most common large predators in their ecosystems:

And as I have said, you cannot compare the ecosystems side by side like that. You have no basis upon which to do so.

White rhino-sized Albertosaurus was the dominant predator of the Judith River, making up about 75 percent of the big-predator fauna.

And I am supposed to take the fact claim if a book written for laypersons in the midst of a large debate within the scientific community on the matter as gospel? Really?

If you factor out humans and the effects of civilization, as well as bears and primates (which are omnivores, getting a large percentage of their food in the form of vegetation) you have the following large, warm-blooded terrestrial meat-eaters:

North America: wolf, puma, jaguar
South America: puma, jaguar
Europe: wolf, lion
Middle East: wolf, lion, leopard, tiger, cheetah, striped hyena
Far East: wolf, leopard, ounce, tiger

I was referring to the fact that most predators are far smaller. Megafauna is a rare exception when it comes to predation both now, and in the past. Most predators, endo or ectothermic are far smaller in scale, and are actually more important in terms of the biomass they consume and the communities they structure. They are also more numerous both in species count and in number of individuals. Predation by non-humans actually has a fairly small impact (generally) on the populations of large grazers/browsers whos communities are regulated bottom-up by food supply more than predation (North america is an exception to this, or was because of the particular ecology of north American browsers like deer)

And what other, larger predators were providing the tyrannosaurs with leftovers?

They dont have to be large. Raptors, of the various species extant at the time, were more than capable of bringing down even the largest of extant herbivores. They just did not do so in solitary fashion. They also would not fossilize as readily as something as large as a tyrannosaur.

Collovosaurus was found in the same part of Mid-Jurassic England as Eustreptospondylus. Each animal is known from one specimen, so going by the fossil record alone, the former was at least as common as the latter.

That is a non-sequiter and you know it. Besides, in order to support a predator population, the prey must be many times more abundant than the species that preys upon it. The rule of thumb is ten times the biomass.

Except Horner isn’t claiming that a few isolated tyrannosaurs may have lived off of what washed up on shore in a few lucky cases where that’s enough for large animals to eat. He claims they were all scavengers and incapable of hunting for reasons that are so laughable that the argument could be made that I’m actually giving him too much credit by calling him a bullshitter.

I am sorry, but I will take the guy with a PhD who studies the behavioral ecology of dinosaurs over you, who relies on the dinosaur encyclopedia and who has no grasp of ecology, evolution, or anatomy any day of the week.

So you concede that there’s no evidence for the first part, right?

Sure. Though it does not preclude a similar encounter happening prior to KT.

If the animal had a bite wound in the tail, it was attacked from behind. You know, since animals’ tails are located in back. Now, if an animal is bitten by another from behind then either the animal doing the biting was hunting or chasing the bitee, or this ridiculous idea that the hadrosaur stumbled across a tyrannosaur, was startled, turned and ran –being bitten in the process. But if Horner was right, and T. rex was incapable of hunting, why would the duckbill (IIRC Edmontosaurus, an enormous plant-eater with little to fear from smaller, scarcer predators) run away?

You saw the video, and changed the subject to starling rather than an attack on offspring. Herbivore attempts to trample baby. Mom intercedes, from behind.

As a rule, defensive bites are not as nasty as predatory ones. A T rex had a bite force of an estimated 30 thousand PSI and teeth perfect for fragmenting bone. If it was a predatory bite, there would not have been a vertebrae left to heal.

You were saying?

Not evidence. There is no reason to think that they presented either of them with the other person's arguments. Moreover, the whole thing was edited together from larger cuts.

Moreover, nothing Curry was saying actually precludes scavenging, if you understand that T Rex evolved from much smaller carnivores.

Binocular Vision: Evolved from a smaller predator, and it would still be helpful in finding a corpse that one has smelled with the massive massive olfactory bulb.

Hearing: Tracking a heard which made low sounds is useful for both a hunter and a scavenger. Think about this for a moment. Unlike a vulture, this animal cannot soar on thermals and find fresh kills. It has to narrow down its searches. Following a specific heard is a good way to do that. Moreover, if T rex made low sounds, say, a mating call, it would be useful to hear this. The hearing could well have been there via sexual selection.

Teeth: Shape--evolved from, smaller predators. The tooth shape would not have needed to change. Rooting--Scavenging, particularly corpses that may have been picked over, also requires large strong serrated teeth.



I note that you completely ignore the citation list.

[Anguirus]

They dont have to be large. Raptors, of the various species extant at the time, were more than capable of bringing down even the largest of extant herbivores. They just did not do so in solitary fashion. They also would not fossilize as readily as something as large as a tyrannosaur.

Aly, I think you are understating the difficulty inherent in taking down an Anatotitan (which is Latin for "50-foot fucking monster") for a pack of 2 meter dromaeosaurs. Yes, wolves can take down moose, but not every day, as the moose tends to take a few pack members with it. This strikes me as much closer to "action movie ecology" as a Tyrannosaur hunting actively.

The big dromaeosaurs like Utahraptor did not co-occur with Tyrannosaurus to my knowledge.

I certainly have no dispute with any of your other observations, however. The problem is that there's only a limited amount of conclusions we can draw about any aspect of Tyrannosaur ecology. Hell, we're not even talking about ecology really, we're talking about biomechanics and then trying to jump to ecology.

Anyway, I know Horner supports a "deadly Earth" sort of hypothesis for the late Cretaceous period. Giant tyrannosaurs could be supported even if they couldn't act as ambush predators if enough large herbivores were conveniently dropping dead. The problem IMO is; how were they then reaching such immense size? (Keep in mind I don't know a blessed thing about the ontogeny of other Cretaceous herbivores, or proportion of juveniles found to adults.)

All parties to this discussion should bear the following in mind: an animal was recently discovered by Paul Sereno called Raptorex that lived well before Tyrannosaurus and was a possible ancestor. This animal was lightly built and only 3 meters long. It has almost the same exact proportions as Tyrannosaurus, head, arms, everything.

It is therefore entirely mistaken to characterize any features of Tyrannosaurus that are shared by Raptorex as adaptations for living as a large, apex predator. Raptorex isn't subject to the same biomechanical arguments against Tyrannosaurus as an active hunter. In fact, they couldn't have had the same feeding ecology, both due to their size difference and due to different ecosystems. The tyrannosaurid body plan was a common and successful one at a variety of sizes, but that doesn't mean that they all hunted and scavenged in equal proportion.

[Akhlut]

Anyway, I know Horner supports a "deadly Earth" sort of hypothesis for the late Cretaceous period. Giant tyrannosaurs could be supported even if they couldn't act as ambush predators if enough large herbivores were conveniently dropping dead. The problem IMO is; how were they then reaching such immense size? (Keep in mind I don't know a blessed thing about the ontogeny of other Cretaceous herbivores, or proportion of juveniles found to adults.)

They (various herbivores) don't necessarily have to be simply dropping dead from diseases or the like; T. rexes could have been large, endurance predators. Humans, hyenas, and several types of canine all simply lope after prey and wait for it to simply collapse from exhaustion and then kill the prey. This may have been a decent way of life for a slow-moving predator like T. rex. It simply has to be plod behind a herd of something until an animal trips, or just runs out of energy and then it just needs to bite the prey on the head and start eating. This is contingent on it being able to maintain a walking pace to keep up with the herd for hours or days, though.

Of course, as you said, we're basically trying to extrapolate from what little we have, so we can't and shouldn't go about making ironclad statements about how creatures that have been extinct for millions of years lived.


Anyway, relating back to the OP a bit: does anyone know if the average sizes for Triceratops sp. and Torosaurus sp. are derived from populations existing mostly in the same areas, or if they are heavily weighted from different areas? That is to say, are Triceratops average sizes skewed because of a large number of huge animals in, say, Wyoming, while we've only found a few dozen Torosaurus fossils from Oklahoma, where Triceratops fossils are smaller than Wyoming specimans? Hopefully that's a clear enough statement.

[Alyrium Denryle]

Aly, I think you are understating the difficulty inherent in taking down an Anatotitan (which is Latin for "50-foot fucking monster") for a pack of 2 meter dromaeosaurs. Yes, wolves can take down moose, but not every day, as the moose tends to take a few pack members with it. This strikes me as much closer to "action movie ecology" as a Tyrannosaur hunting actively.

The big dromaeosaurs like Utahraptor did not co-occur with Tyrannosaurus to my knowledge.

Sure, but there were other species around to prey upon in that region, and nothing says that they would be taking down healthy adult individuals. Dinosaurs have a long history of using sheer size to deter predation. The Juvies, which would have outnumbered adults by a wide margin were still on the menu.

And bear in mind, I do not support horners conclusions, only his logic and credentials. My preferred explanation is T rex is this:

They (various herbivores) don't necessarily have to be simply dropping dead from diseases or the like; T. rexes could have been large, endurance predators. Humans, hyenas, and several types of canine all simply lope after prey and wait for it to simply collapse from exhaustion and then kill the prey.

I certainly have no dispute with any of your other observations, however. The problem is that there's only a limited amount of conclusions we can draw about any aspect of Tyrannosaur ecology. Hell, we're not even talking about ecology really, we're talking about biomechanics and then trying to jump to ecology.

Yes

Anyway, I know Horner supports a "deadly Earth" sort of hypothesis for the late Cretaceous period. Giant tyrannosaurs could be supported even if they couldn't act as ambush predators if enough large herbivores were conveniently dropping dead. The problem IMO is; how were they then reaching such immense size? (Keep in mind I don't know a blessed thing about the ontogeny of other Cretaceous herbivores, or proportion of juveniles found to adults.)

Just like turtles (or like certain large extant archosaurs that got sexually molested by the late Steve Erwin). High juvenile mortality, low adult mortality. Those that do survive their juvenile years keep churning out babies over the course of a long reproductive lifespan.

Anyway, relating back to the OP a bit: does anyone know if the average sizes for Triceratops sp. and Torosaurus sp. are derived from populations existing mostly in the same areas, or if they are heavily weighted from different areas? That is to say, are Triceratops average sizes skewed because of a large number of huge animals in, say, Wyoming, while we've only found a few dozen Torosaurus fossils from Oklahoma, where Triceratops fossils are smaller than Wyoming specimans? Hopefully that's a clear enough statement.

It is clear. Which is another point. We may not actually be dealing with the same species of triceratops in different localities. Skeletal features are not the only thing that determines if something is a species or not. The skeletons of many frogs for example are basically identical except for maybe size, and we know they are different species. It is like having frog skeletons from across the US and calling them all Rana pipiens... oh wait, we had that for a hundred years with full specimens...

[Anguirus]

Sure, but there were other species around to prey upon in that region, and nothing says that they would be taking down healthy adult individuals. Dinosaurs have a long history of using sheer size to deter predation. The Juvies, which would have outnumbered adults by a wide margin were still on the menu.

And bear in mind, I do not support horners conclusions, only his logic and credentials. My preferred explanation is T rex is this:

Indeed, that's all true.

I must say, I also like the idea that T. rex family groups hunted in conjunction, with juvies flushing prey into the exceedingly deadly jaws of their mother.

I think one reason that most of us resist a scavenging T. rex is because very large theropods are the rule in Mesozoic ecosystems, not the exception. T. rex is big (bigger than an elephant) but not the biggest. I haven't scanned the literature, but I don't believe that other large theropods have been deemed to be so limited in their hunting capabilities. And I don't see any reason why giant herbivores would be drastically faster and more agile than giant tyrannosaurids. Granted, its ability to hide and to sprint are dubious, but as you point out, there are other hunting methods. It just seems reasonable to think that large herbivores would drive the evolution of large carnivores.

This isn't a serious criticism of Horner, of course...frankly, I don't have the time, motivation, or qualifications to offer one at this time.