What's your Fav Dinosaurs?

[Gnosis of Disbelief]

I've been reading up on the debate over whether T-Rex was a scavenger or predator, and the most common answer I keep coming across is both. Any predator is happy with a free meal so will scavenge if they can, but if they can't they have the ability to kill.

 

Some things about the T-Rex's build:

Speed - Yes T-Rex wasn't a cheetah, but it didn't have to be. It simply had to move faster than its prey (certainly Triceratops or Ankylosaur were not faster than T-Rex).

Smell - Yes T-Rex had a great sense of smell, this does not dismiss it as a predator as we know of many that have good sense of smell (wolves, sharks etc).

Teeth - It is suggested that rounder teeth are better for crushing than cutting, but they are also better for grabbing and holding live prey.

Amount of food - A T-Rex would weight between 5-7 tons, as such if it was solely a scavenger it would require huge amounts of dead creatures to litter the countryside. Of course there had to be a surviving population of T-Rex at some point, and it seems unreasonable to account for their entire dining habits on carrion.

 

 

Isn't it fairly common for predators to also be scavengers? I know that

bald eagles, for example, will just as readily devour a dead fish on a

river bank as catch one themselves.

[Mr. Neil]

It's not so much the powerful sense of smell that makes it such a likely candidate for being a scavenger. It's the combination of having a great sense of smell and poor eyesight and vestigial arms.

 

You have to put the puzzle pieces together. You have an animal that, even if it could run, can't catch anything, because it doesn't have any arms, and it can't afford to chase anything, because it can't pick itself back up if it falls down.

 

Now, as far as getting a meal, John Horner has suggested that the size of T-Rex may have been to its advantage, because being big allows such an animal to chase away other predators.

[scitsofreaky]

Mr Neil, I don't think we will ever rid society of the idea of T-Rex as a predator, it's just too damn cool to think of something that big running down and killing its prey like in the movies.

Velociraptor is just cool, but so is Oviraptor (spelling?). Ah hell, anything with raptor in the name or like a raptor.

[Wertbag]

You have to put the puzzle pieces together. You have an animal that, even if it could run, can't catch anything, because it doesn't have any arms, and it can't afford to chase anything, because it can't pick itself back up if it falls down.

Predators don't require arms to catch prey, don't need speed (surprise, stealth, patience, teamwork etc can all be used) and eyesight is also dependant on the size of prey (eagles have great eyesight but are picking out rodents or fish, while lions have worse eyesight but adaquate for wildebeast) you wouldn't need great eyesight to spot a 5 ton prey walking about...

 

So you have an animal that can run at a speed fast enough to out run its main prey (such as Triceratops), that has enough jaw strength to break bones and tear through thick hide, that may have worked in family units, and a sense of smell that could lead it to prey when line of sight was blocked (much better to hunt in jungles by smell or stealth as line of sight can only be measured in meters).

 

Of course we will never know as its long extinct. I would still like to hear if there is any point to the arms? Regardless of its eating habits the arms just seem completely useless...

[Caretaker]

Photo of Rock-Et-Man

 

http://www.i-am-bored.com/bored_link.cfm?link_id=6570

[Mr. Neil]

Predators don't require arms to catch prey, don't need speed (surprise, stealth, patience, teamwork etc can all be used)

I'm trying to picture a stealthy T-Rex waiting patiently in the brush while it's pack circles around to the other side of the prey.

 

Actually, every predator that I can think of off the top of my head uses its limbs to catch prey. The lion uses its front paws to latch onto animals in the field, and of course birds catch things with their talons. The only exceptions I can think of would be insectavores and fish-eating birds, both of which use their mouths as a primary attack weapon, but neither of which is comparable to a T-Rex.

 

and eyesight is also dependant on the size of prey (eagles have great eyesight but are picking out rodents or fish, while lions have worse eyesight but adaquate for wildebeast) you wouldn't need great eyesight to spot a 5 ton prey walking about...

But this is an animal with eyesight that is particularly bad. The thing probably couldn't even see at night.

 

Again, this is sort of a disassembly of the traits that make T-Rex a terrible candidate as a hunter. We can draw parallels to other animals that have similar difficiencies for each of those lacking in T-Rex, but are capable of making up for deficiencies with other traits. You have to put the pieces together.

 

For example, T-Rex couldn't run, so you suggested stealth as an alternative. But does T-Rex strike you as a very stealthy animal? I may have to look into the eyesight to lions, but lions have packs to make up for their individual deficiencies. Where is the evidence for this in T-Rex?

 

The sense of smell is a serious factor here. You have to consider natural selection here. T-Rex has the second-largest olfactory lobe of any species in the fossil record. This is suspicious, even for a predator. Predators that can hunt need a strong sense of smell, but not that strong. You have to remember that predators are outnumbered, so they really don't have to walk very far to find prey. And yet, here's this gigantic animal that can not only smell all of the animals in the immediate area, it could smell dead things for miles around.

 

Of all the animals that are known which share similar features with T-Rex, the ones that match most closely are the scavengers. The combination of features is very unlike predators. It's a matter of doing some rethinking. Are we following the evidence to its natural conclusion, or are we trying to make T-Rex fit into a preceived notion? I had a tough time with this as well, but I also realized that in order to hang onto T-Rex the predator, I had to make generalized excuses for each of the deficiencies in the creature without having to deal with the animal on a whole.

 

So you have an animal that can run at a speed fast enough to out run its main prey (such as Triceratops), that has enough jaw strength to break bones and tear through thick hide, that may have worked in family units, and a sense of smell that could lead it to prey when line of sight was blocked (much better to hunt in jungles by smell or stealth as line of sight can only be measured in meters).

It's very difficult to take the problem in the mental image I keep coming up with and transferring it into words. I'm not saying that T-Rex's jaw couldn't kill efficiently, because obviously it could. The problem I keep having is the lack of arms. I'll try to relate the image in my head as best I can.

 

Again, giving T-Rex the benefit of the doubt that it could keep up with its prey, try to imagine a T-Rex chasing a Triceritops. Heck, make it Edmontosaurus, because there's more potential biting area on that animal than the barrel-shaped Triceritops. Now, let's say that T-Rex caught up to this animal and is ready to make the kill. How does it do it? Does it run along side and crane it's neck over to make a bite? With an animal that's 40 feet high off the ground, I would worry about it losing its balance and falling if it missed. Again, if T-Rex falls, it's fucked.

 

I can't picture T-Rex realistically catching anything. Again, the concept of the family pack comes up, but what's the evidence for that?

 

Another problem brought up by John Horner is the fossil evidence of prey. There are fossilized carcasses that show to be eaten fed off of by predators, and there's evidence of T-Rex eating from prey carcasses. The interesting thing, however, is that there's no evidence that the T-Rex actually killed it.

 

Horner goes into detail about this on a Science Channel program. I'm operating off of memory. I think the program was called "Tyrannosaurus Rex: Warrior or Wimp". Or something like that.

 

Of course we will never know as its long extinct. I would still like to hear if there is any point to the arms? Regardless of its eating habits the arms just seem completely useless...

Basically what I stated above. If it catches up with a fleeing herbivore, how does it catch it without risking its stability?

[Emperor Norton II]

Styracosaurus- it just LOOKS scary.

 

Allosaurus is another big favorite.

 

Utahraptor is probably number one, though. Raptor Red was an amazing book.

[Hero of Hyrule]

Actually, every predator that I can think of off the top of my head uses its limbs to catch prey. The lion uses its front paws to latch onto animals in the field, and of course birds catch things with their talons. The only exceptions I can think of would be insectavores and fish-eating birds, both of which use their mouths as a primary attack weapon, but neither of which is comparable to a T-Rex.

 

Wolves don't use their limbs when attacking as far as I know.

Crocodiles don't use their limbs.

Snakes don't.

 

But I don't think any modern animal can be used as an example for dinosaur hunting. Predatory dinosaurs are among the very few animals who walk on their hind limbs. And while T-rex's arms are very small most other big predators have small arms too.

 

Probably my dinosaur knowlege is very outdated but why would T-rex have a problem with getting up and Allosaurus won't?

 

Just tought up something Extr...Giant running predatory birds like Diatryma also have no hands or anything...And they even lack the tail for balance.

[Gnosis of Disbelief]

Even if the T. Rex were mainly a scavenger, I find it hard to believe

that it wouldn't pass up an easy snack - e.g., an injured, sick, or dying

animal. In our times, scavengers like ravens have been known to pick

off baby birds in their nests. I seem to recall that certain species of

vultures can be predatory on dying animals, but I would have to do

some reading to verify this.

[♦ nivek ♦]

I kinda like to use my cardboard box *Wayback Machine* and shoot a young Brontosaur hen.. Broiled with onions and garlic, they are delicious..

 

kL

[Mr. Neil]

Wolves don't use their limbs when attacking as far as I know.

*sigh* Alright, alright... You got me on that one. But wolves are pretty fast, too. And they hunt in packs. They don't need to use their forelimbs.

 

Crocodiles don't use their limbs.

Crocs are water predators. Not comparable.

 

Snakes don't.

Damnit. I forgot about them. But snakes also have the advantage of stealth. And in some cases, poison.

 

I mean, I understand your point. I goofed in my assertion, but snakes... aren't... really... comparable.

 

But I don't think any modern animal can be used as an example for dinosaur hunting. Predatory dinosaurs are among the very few animals who walk on their hind limbs. And while T-rex's arms are very small most other big predators have small arms too.

But at least they can use them. T-Rex, once you assemble all the musculature, doesn't really have arms at all.

 

Try getting up off the ground without using your arms at all. And after you do it the first time, do it again, only this time, don't use your forward rolling momentum to snap up to your feet, smartass. It's pretty tricky when you can't assist your legs when getting up. And even then, we still have an unfair advantage over T-Rex, because we can use our knees for support.

 

Probably my dinosaur knowlege is very outdated but why would T-rex have a problem with getting up and Allosaurus won't?

Allosaurus has use of its arms. They're not long, but they're usable, and they make a huge difference for what they are.

 

Just tought up something Extr...Giant running predatory birds like Diatryma also have no hands or anything...And they even lack the tail for balance.

Yes, but again, I made a point about how high T-Rex was off the ground. T-Rex had a very high center of balance. The giant killer birds, with their balance set lower, would be a lot tougher to knock down.

[Mr. Neil]

Also, don't get me wrong. This is much more fruitful than arguing with txviper. Actually, it's uncomparable, because txviper has no choice but to be wrong. This, on the other hand, actually bears a reasonable discussion.

 

John Horner does a little bit of talking about the T-Rex in his lecture at Princeton back in 2003. He also talks about the changing scope of dinosaurs and how we learn new things all the time; a nod to tentativeness that I think txviper could stand to listen to.

 

That lecture can be found on this page: http://www.princeton.edu/WebMedia/lectures/

 

Mind his hair, though. That's a terrible hairdo. He looks like he was separated at birth from Cooky the Clown.

[Hero of Hyrule]

Crocs are water predators. Not comparable.

 

Not all the time.

 

Well I admit that getting a T-rex up on it's feet again would be pretty hard.

 

Some species have to be scavangers...Ad there are enough other big dinosaur predator who did have arms.

[Mr. Neil]

Another point brought up by Horner, one which is an evolutionary argument, is that one explanable reason for the tyrannosaurs losing their arms with each new species is perhaps because they're not using them.

[Wertbag]

Personally my mental image of a T-Rex attacking a creature would closely match a croc hit. Bite with great jaw pressure, then by shaking and use of body weight (obviously wouldn't expect a T-Rex to death roll!) cause great internal damage and death. Of course we don't have any large land predators that would have hunted or killed like a T-Rex to compare to. The largest land predator now days is the grizzly, but due to its physical differences there is little simularity. Maybe large lizards such as the komodo dragon would be the closest match? Certainly no arms used but still effective predators.

 

There are several other things that point to T-Rex as a predator. The eyes on the T-Rex are angled forward allowing it to focus both eyes on a target at the same time. Obviously this would give good depth preception allowing T-Rex to judge distance. Depth preception is a great benefit to a predator but of little benefit to a scavenger.

Also this quote from a website I was reading:

"An Edmontosaurus skeleton at the Denver Museum of Nature and Science has a bite taken out of the top of its tail that closely matches the size and shape of a Tyrannosaurus rex tooth row (although the rumor that T. rex tooth fragments were found embedded in the bone are unfounded.) Dr. Ken Carpenter found evidence that the bone had re-healed after the bite was taken, so the wound is the signature of an active predator."

[Mr. Neil]

Personally my mental image of a T-Rex attacking a creature would closely match a croc hit. Bite with great jaw pressure, then by shaking and use of body weight (obviously wouldn't expect a T-Rex to death roll!) cause great internal damage and death.

Well, that part, I could certainly understand. That bite could just about kill anything.

 

But the problem, as I'm having difficulty expressing, is not that the mouth is great for killing, but rather how the animal positions itself for a kill while in a chase. It can't just catch-up and bite, like Pac-Man. It lives in 3-D universe. If it manages to catch up with a prey (which is being biomechanically generous), it would have to somehow position its mouth for the kill as it's in persuit, which would mean craning its head over as it's running along side, and risk falling over or being yanked off it's feet if the bite isn't an immediate kill. Unless it could somehow blindside the animal, where a cleaner bite would be far easier to obtain, I have difficulty seeing how a T-Rex could catch anything.

 

Again, the fossil finds are quite telling. T-Rex feedings are easy enough to identify, including some where the animal was feeding almost exclusively from the underside of the animal, but never has a T-Rex kill been discovered. A T-Rex kill should be obvious. Just look for crushed vertibrae.

 

Of course we don't have any large land predators that would have hunted or killed like a T-Rex to compare to. The largest land predator now days is the grizzly, but due to its physical differences there is little simularity. Maybe large lizards such as the komodo dragon would be the closest match? Certainly no arms used but still effective predators.

But don't you see what I'm saying? The tyrannosaurs, as you go through the fossil record, are slowly losing their arms. Why would a predator slowly lose a somewhat valuable feature? Unless it wasn't using them.

 

There are several other things that point to T-Rex as a predator. The eyes on the T-Rex are angled forward allowing it to focus both eyes on a target at the same time. Obviously this would give good depth preception allowing T-Rex to judge distance. Depth preception is a great benefit to a predator but of little benefit to a scavenger.

Well, look where the T-Rex comes from. The T-Rex is now thought to be from the line of decent as the raptors, and they had that feature, too. T-Rex also has a raptor-exclusive pinched-bone feature in its foot, which is advantageous for running. Unfortunately, the rest of its leg isn't, so there's another feature that T-Rex has that it can't really use to its full potential. Sure, T-Rex is going to have some throwbacks to its ancestory, but the optic lobes of its brain were so small that it almost doesn't matter where its eyes were pointed.

 

"An Edmontosaurus skeleton at the Denver Museum of Nature and Science has a bite taken out of the top of its tail that closely matches the size and shape of a Tyrannosaurus rex tooth row (although the rumor that T. rex tooth fragments were found embedded in the bone are unfounded.) Dr. Ken Carpenter found evidence that the bone had re-healed after the bite was taken, so the wound is the signature of an active predator."

I've seen that fossil. Not in person, mind you, but I've seen all sorts of pictures of it and a demonstration by Dr. Carpenter on TV. What it amounts to is a single gap in the animal's vertibrae in which a single T-Rex tooth just happens to fit. What Dr. Carpenter didn't explain, unfortunately, is how a T-Rex might manage to bite an animal with only one tooth.

 

I'm not entirely ruling it out, but it's a very strange find, indeed.

[Wertbag]

If it manages to catch up with a prey (which is being biomechanically generous)

Its not biomechanically a problem at all, T-Rex only has to outpace the slow herbivores of the day. Even the site you link to says:

"And while that's a considerably slower than many have thought, he notes that the large herbivore dinos that T. rex ate are also subject to the same limitations. They were slow-moving beasts as well. "

 

Again, the fossil finds are quite telling. T-Rex feedings are easy enough to identify, including some where the animal was feeding almost exclusively from the underside of the animal, but never has a T-Rex kill been discovered. A T-Rex kill should be obvious. Just look for crushed vertibrae.

Of course finding eaten fossils is never an easy task at the best of times. To fossilise the carcass must be buried and remain so. Usually a killed animal dies in an open area where it is destroyed by scavengers. Sadly due to the fossilisation process finding kills is more luck than expectation.

 

I have heard one tack used by predator supporters that I'm not really convinced by myself, but will include for completeness. The idea being that the main herbivores had evolved defences (horns, ball tail, spines etc) which are obvious signs of protection vs large predators. The thought being that T-Rex was the only large predator of its time so such defences would be aimed at it.

To my mind evolution of such defences would be a very long slow process, and to point at any one cause for such evolution doesn't follow for me.

 

Other arguements I've heard:

-the Tyrannosaurs naris (nostrils holes) are very far forward on the snout, even more so than most other dinosaurian predators, which is inconsistent when compared with the more successful scavengers of today; they normally have the nostrils farther back on the snout as the softer, more decayed gore tends to get clogged in their nostrils.

-the skull has several projections (like the supraoccipital crest and orbital brow bones), some of which were quite large and would have even been larger in life when a coat of keratin would have covered them. Scavengers usually have 'slicked down' skulls to burrow into the corpse, not projections which would get caught up and make this hard for a tyrannosaur.

-as herbivores got larger, so did the carnivores. Tyrannosaur’s large size would obviously have been unnecessary if it was a scavenger, it could have remained as small as the creature it evolved from originally or possibly even decreased in size, as it doesn’t take size to eat a corpse. Again, compare the scavengers of modern day with the scope of size in the age of the dinosaurs.

-The lung size of the T-Rex is huge. A scavenger does not require large lungs, while a predator that intends to chase or fight does.

-Dogs have small eyes and relatively small optic lobes, and huge olfactory bulbs. And they’re obviously great hunters. There is no reason to say that good smell can only be used for sniffing out corpses, or why predators must rely entirely on sight.

 

The main three points that are used to show T-Rex as a scavenger are short arms (but we can show several examples of armless predators), good sense of smell (but we can show several examples of great scent predators) and speed (but we can show the prey was slower than the T-Rex estimates, and even those estimates cannot be agreed upon by scientists).

Those to me point to a different type of predator, but does not automatically fit a scavenger.

[Mr. Neil]

Its not biomechanically a problem at all, T-Rex only has to outpace the slow herbivores of the day. Even the site you link to says:

"And while that's a considerably slower than many have thought, he notes that the large herbivore dinos that T. rex ate are also subject to the same limitations. They were slow-moving beasts as well. "

Yes, and we keep going back to this point where we say that T-Rex only had to be able to catch up with his prey. But there's more to it than that. I keep raising the point about how the animal is supposed to maintain stability when it can't grab anything. This is an animal that can't afford to persue, because it's in trouble if it falls down.

 

Of course finding eaten fossils is never an easy task at the best of times. To fossilise the carcass must be buried and remain so. Usually a killed animal dies in an open area where it is destroyed by scavengers. Sadly due to the fossilisation process finding kills is more luck than expectation.

Fair enough, but it is rather interesting that the known fossilized remains fed on by a T-Rex show to be scavenged.

 

I have heard one tack used by predator supporters that I'm not really convinced by myself, but will include for completeness. The idea being that the main herbivores had evolved defences (horns, ball tail, spines etc) which are obvious signs of protection vs large predators. The thought being that T-Rex was the only large predator of its time so such defences would be aimed at it.

To my mind evolution of such defences would be a very long slow process, and to point at any one cause for such evolution doesn't follow for me.

Well, those animals in question actually originate from a period in which the smaller raptorial dinosaurs were the top predators. Those should not be confused as evolutionary adaptations to T-Rex.

 

Other arguements I've heard:

-the Tyrannosaurs naris (nostrils holes) are very far forward on the snout, even more so than most other dinosaurian predators, which is inconsistent when compared with the more successful scavengers of today; they normally have the nostrils farther back on the snout as the softer, more decayed gore tends to get clogged in their nostrils.

Except that T-Rex wouldn't have to scavenge the way a heyina or vulture would. It could basically crush the bones to find whatever it wanted.

 

-the skull has several projections (like the supraoccipital crest and orbital brow bones), some of which were quite large and would have even been larger in life when a coat of keratin would have covered them. Scavengers usually have 'slicked down' skulls to burrow into the corpse, not projections which would get caught up and make this hard for a tyrannosaur.

I realize that these are not your arguments. I'd have to see that there is actually a reason for this distinction.

 

-as herbivores got larger, so did the carnivores. Tyrannosaur’s large size would obviously have been unnecessary if it was a scavenger, it could have remained as small as the creature it evolved from originally or possibly even decreased in size, as it doesn’t take size to eat a corpse. Again, compare the scavengers of modern day with the scope of size in the age of the dinosaurs.

Well, you also have to look at what kind of predators T-Rex was up against. T-Rex had some nasty competition, like the swift-running Troadon. Size may not be necessary to feed of of carcasses, but it sure comes in handy if you have to steal someone else's dinner.

 

 

-The lung size of the T-Rex is huge. A scavenger does not require large lungs, while a predator that intends to chase or fight does.

Strange that it would have a large lung capacity. I don't really have a comeback for that, but there are always some weird exceptions to any species you find in the wild; some feature you didn't expect. I wouldn't throw out an entire theory on one anomoly.

 

I could make the same argument about the animal's sense of smell. A predator doesn't need the second-largest olfactory lobe in the fossil record. It's every bit as much overkill for a predator to have such a strong sense of smell as it is a scavenger to have a high lung capacity.

 

-Dogs have small eyes and relatively small optic lobes, and huge olfactory bulbs. And they’re obviously great hunters. There is no reason to say that good smell can only be used for sniffing out corpses, or why predators must rely entirely on sight.

A couple of differences, though. Dogs are pack animals. They're also much faster and much smarter than T-Rex.

 

There's also a difference in how the nose works. A dog's nose isn't just built to smell, but to also exhale very rapidly, kicking up particles for the dog to smell, which makes the dog's nose clearly adapted for persuit. There's no such adaptation on T-Rex.

 

And the last point I'd like to make (again realizing that these are not your arguments) is this particular selection actually misrespresents the contention of the scavenger theory. It's not to say that a good sense of smell can only belong to that of a scavenger. It's that the combination of features, that being poor eyesight, good smell, the loss of forelimbs, and loss of speed.

 

Again, the loss of forelimbs indicates that T-Rex aparently wasn't using them, and it seems odd that an animal like T-Rex, which evolved from the best runners in the dinosaur family, would evolve into a slow, lumbering brute.

 

The main three points that are used to show T-Rex as a scavenger are short arms (but we can show several examples of armless predators), good sense of smell (but we can show several examples of great scent predators) and speed (but we can show the prey was slower than the T-Rex estimates, and even those estimates cannot be agreed upon by scientists).

Those to me point to a different type of predator, but does not automatically fit a scavenger.

Well, this seems to be an error of composition. Yes, you keep bringing up animals that have similar features to T-Rex, but you're not really addressing the complete package.

 

For example, finding armless predators is one thing, but the predators you're mentioning are clearly built for hunting, like dogs, snakes, and crocodiles. And in many of these cases, it's apples and oranges. None of these animals have the anatomical height of T-Rex. Snakes, crocs, and dogs don't have to worry about what they're going to do if they fall down. You seem to be misunderstanding the point of the arm argument.

 

And then you say you can show predators with fantastic smell. But that's irrelevent, because I'm not saying that predators can't have great smell. Of course some predators are going to have a great sense of smell. That's not the point. It's the T-Rex's suspiciously outstanding sense of smell, combined with these other features, that make it a scavenger candidate.

 

And finally, we have speed. I don't know where it's shown that the prey is actually slower than T-Rex, but I do know that there were other predators walking around the Cretacious with T-Rex, and they were all adapted for speed, showing us that running was still a good thing for predators to have back in the Cretacious, some 65-70 million years ago.

 

You keep trying to break these down individually to explain each of them away, but you're not looking at all of these features as they're presented in a single animal, and you're not considering its evolutionary path. This is an animal that evolved from the most specialized hunters in the dinosaur kingdom, yet it's lost everything that made the raptors advantageous as hunters.

 

Why would the T-Rex lose its arms unless it wasn't using them?

[scitsofreaky]

I read something about how T-Rex may have hunted that was interesting. Keep in mind that I read this about 10 years ago. It said that perhaps T-Rex was an ambush predator of sorts (which is hilarious to think about) that would kill its prey by running head long with its mouth open into the prey. The force of the collision, it said, would have either outright killed the animal or would have stunned it long enough for the T-Rex to give a killing bite. Hilarious, I know, but it was interesting.

I think we can all agree that T-Rex did at least some scavaging. I wouldn't be surprised if T-Rex would also take any prey of opportunity, such as a weak or crippled animal. The reason I say this is because I saw a show on Discovery that showed evidence for a fight between a T-Rex and a triceratops that had a broken off horn.

[Mr. Neil]

I read something about how T-Rex may have hunted that was interesting. Keep in mind that I read this about 10 years ago. It said that perhaps T-Rex was an ambush predator of sorts (which is hilarious to think about) that would kill its prey by running head long with its mouth open into the prey.

See, now that might work. I have difficulty imagining T-Rex as a chase-and-fight predator, because of easy it would be to just knock the thing over. Seriously, every time fighting came up, I was like, "Fighting?! What fighting?!"

 

T-Rex's only weapon is its mouth, so in order to do any killing, it has to be able to do it with as little struggling as possible. A quick bite to the neck would do it. I'm having a little trouble with T-Rex as a stealth animal, but if it had a pack mentality, then maybe...

 

The force of the collision, it said, would have either outright killed the animal or would have stunned it long enough for the T-Rex to give a killing bite. Hilarious, I know, but it was interesting.

Indeed. Imagining a T-Rex sneaking up on anything is downright hilarious. It's like having an elephant in the room.

 

I think we can all agree that T-Rex did at least some scavaging. I wouldn't be surprised if T-Rex would also take any prey of opportunity, such as a weak or crippled animal. The reason I say this is because I saw a show on Discovery that showed evidence for a fight between a T-Rex and a triceratops that had a broken off horn.

See, now that's the kind of stuff I'd be interested to see.

 

Also, I agree that if T-Rex had the opportunity to kill something, it probably would. It might not be able to chase it, but if it's wounded, then the T-Rex has an easy hunt.

[Wertbag]

Yes, and we keep going back to this point where we say that T-Rex only had to be able to catch up with his prey. But there's more to it than that. I keep raising the point about how the animal is supposed to maintain stability when it can't grab anything. This is an animal that can't afford to persue, because it's in trouble if it falls down.

That point also seems to be quite debatable. Animals such as chickens which have a similar walking style and no arms can regain their feet without trouble. Larger animals such as elephants can be knocked onto their side, and still regain their feet (obviously not elegantly but still easily). The mental image that is given by the description "in trouble if it falls down" is of a turtle on its back, unable to stand and eventually starving to death. You paint a picture of the T-Rex being on rollerskates, barely able to walk for fear of tripping.

 

Fair enough, but it is rather interesting that the known fossilized remains fed on by a T-Rex show to be scavenged.

Of course the debate isn't scavenger vs predator, its whether it was exclusively scavenger or did it do both? There is hardly any predator which would give up a free meal, so there is no doubt that T-Rex did scavenge. Of course as scitsofreaky points out the T-Rex would have quite happily eaten sick or injuried creatures as well, although that doesn't really count as hunting but more opportunity kills. With that in mind even if a fossil of a killed dino was found would it be proof of a predator over an opportunity kill?

I believe its quite rare to find an exclusive scavenger nowdays. Hyenas hunt, vultures will kill if its easy enough etc.

 

A predator doesn't need the second-largest olfactory lobe in the fossil record. It's every bit as much overkill for a predator to have such a strong sense of smell as it is a scavenger to have a high lung capacity.

I've heard that the T-Rex had the second largest sniffer, what creature had the largest?

I'm guessing we may not know this, but with a giant shark like Megaladon, which would have had a great sense of smell as is usual with most sharks, is there anyway for us to know exactly how good its senses were? Usually we are only left with the jaw of the shark, so it doesn't give alot of fossil evidence to work with...

 

Again, the loss of forelimbs indicates that T-Rex aparently wasn't using them, and it seems odd that an animal like T-Rex, which evolved from the best runners in the dinosaur family, would evolve into a slow, lumbering brute.

As the herbivores increased in size so did the carnivores.

I think there is still alot we don't know and will never know due to discussing a creature 65 million years old (or 6000 years if you're a YEC!). What colour was it? How did it care for its young? Did the family unit stay together? What design were its internal organs? I believe even the question of whether it was warm or cold blooded it up for debate...

There was another point that I've seen raised but one that was another hard one to know due to our lack of knowledge. The amount of meat a T-Rex would have consumed a day has been guessed at 10% of body weight based on predators today. Of course cold bloodied or other evolutionary traits may change this which is where our lack of knowledge limits our research. The point made was that due to competition a food source that could be scavenged would be only available for a short time. So for a surviving population of T-Rex's to survive solely on scavenged carcasses would require vast amounts of dead animals. We would require corpses to litter the plains, and dinos to be dropping dead or hunted but not consumed on a very regular basis. It was suggested that T-Rex would have had to hunt simply because it is unreasonable to expect such a large creature to be able to find enough carrion to support a population.

 

Why would the T-Rex lose its arms unless it wasn't using them?

Undoubtedly it wasn't using them. It appears to have relied on its jaws for killing. As the jaws increase in size the need for arms as an attacking tool lessen. Why scratch something when a bite can tear it in half? You have multiple attacking tools, one of which evolved superior to the others and became the prime mode of attack, therefore the others slowly reduced.

 

This is an animal that evolved from the most specialized hunters in the dinosaur kingdom, yet it's lost everything that made the raptors advantageous as hunters.

It gained improved sense of smell, size, power, bite strength. It moved from an animal that relied on packs to an animal that could be a serious threat on its own or with a small family group. Its own size made it top of the food chain, thereby removing the threat of other predators to it.

 

you're not really addressing the complete package.

Well scientists who have studied the related fields for decades have not agreed on an answer so I don't think its going to be a clear cut case either way.

The complete package as I see it: A giant predator top of the food chain, fast enough to outrun the main food sources such as triceritops, jaw strength powerful enough to kill with one good bite, eyes forward for depth perception, sense of smell that would allow it to hunt in areas of poor visibility such as forests, large lung capacity to allow for chasing or fighting, a creature that wouldn't pass up a free meal if offered but powerful enough to make a meal if the countryside wasn't littered with corpses.

 

Of course theres one arguement which its completely airtight... Christian Science to the rescue! Noah took two T-Rex's on the boat, feed them from his magical meat source, but when the boat landed there were no carcasses to scavenge (obviously all were buried to form the fossils), so the T-Rex had to rely on hunting the other animals, and hence why there are no dinosaurs today. It ate 'em all! Obviously if it was only a scavenger it wouldn't have survived the flood.

[Mr. Neil]

That point also seems to be quite debatable. Animals such as chickens which have a similar walking style and no arms can regain their feet without trouble. Larger animals such as elephants can be knocked onto their side, and still regain their feet (obviously not elegantly but still easily). The mental image that is given by the description "in trouble if it falls down" is of a turtle on its back, unable to stand and eventually starving to death. You paint a picture of the T-Rex being on rollerskates, barely able to walk for fear of tripping.

No, I think you've missed the point. That's not what I'm saying at all. I'm saying that with only two legs and not much else to bring itself back to it's feet, it can't really afford to put itself in a situation where it could fall down. It's not a matter of the animal being particularly clumsy.

 

Animals do fall down from time to time. They can be knocked down, trip, slide on rocks; whatever. The T-Rex is a very tall animal, and it's center of balance of somewhere between thirty and forty feet off the ground. This is not an animal that can afford to put itself in a situation where it could be knocked down. A very good situation in whiched to be knocked down just happens to be while hunting, because it's trying to persue, trap, fight, or subdue another animal.

 

I'm gonna skip a couple quotes, just because I have nothing to add. Hope you don't mind.

 

I've heard that the T-Rex had the second largest sniffer, what creature had the largest?

I'm guessing we may not know this, but with a giant shark like Megaladon, which would have had a great sense of smell as is usual with most sharks, is there anyway for us to know exactly how good its senses were? Usually we are only left with the jaw of the shark, so it doesn't give alot of fossil evidence to work with...

Apples and oranges. A shark is not a land predator. The sea is a completely different environment.

 

And actually, the largest olfactory lobe belongs to the turkey vulture.

 

As the herbivores increased in size so did the carnivores.

I think there is still alot we don't know and will never know due to discussing a creature 65 million years old (or 6000 years if you're a YEC!). What colour was it? How did it care for its young? Did the family unit stay together? What design were its internal organs? I believe even the question of whether it was warm or cold blooded it up for debate...

There was another point that I've seen raised but one that was another hard one to know due to our lack of knowledge. The amount of meat a T-Rex would have consumed a day has been guessed at 10% of body weight based on predators today. Of course cold bloodied or other evolutionary traits may change this which is where our lack of knowledge limits our research. The point made was that due to competition a food source that could be scavenged would be only available for a short time. So for a surviving population of T-Rex's to survive solely on scavenged carcasses would require vast amounts of dead animals. We would require corpses to litter the plains, and dinos to be dropping dead or hunted but not consumed on a very regular basis. It was suggested that T-Rex would have had to hunt simply because it is unreasonable to expect such a large creature to be able to find enough carrion to support a population.

Actually, it's been suggested that while dinosaurs could probably generate their own body heat, they probably were not homeothermic (i.e., holding a constant body temperature), which means that their rate of consumption may not be comparable to warm-blooded animals of today.

 

You'll find the same problem with available food among the sauropods, a close relative of the therapods. I don't have any hard number here, but the way some paleontologists have done their homework, the amount of available food for the sauropods doesn't work if we assume that the animals are homeothermic, but the problem pretty much goes away once you start considering other alternatives, and it doesn't even have to bring cold-bloodedness into the picture.

 

And then a similar problem is found in the Jurassic fossils of the Gobi desert. The interesting thing about this environment is that it paints a picture in wich carnivores and scavengers out-number the herbivores, and yet it's a carnivore paradise. How could this be? ...unless the animals are not homeothermic.

 

And of course, one of the most famous predator dinosaurs, the Velociraptor, just happened to be part of this strange predator-heavy Gobi ecosystem. And who just happens to be a close relative of the raptor dinosaurs?

 

T-Rex.

 

Undoubtedly it wasn't using them. It appears to have relied on its jaws for killing. As the jaws increase in size the need for arms as an attacking tool lessen. Why scratch something when a bite can tear it in half? You have multiple attacking tools, one of which evolved superior to the others and became the prime mode of attack, therefore the others slowly reduced.

But that's circular. That's assuming that the mouth was used for attacking. This is not an animal built for hunting. A mouth that kills needs a body that can put up fight or at least provide some means of defense.

 

You also greatly undermine the purpose of arms and forelimbs. They're not just for scratching but for grabbing, holding, picking yourself up when you fall down, etc. Arms are pretty handy if you're able to hold your prey as you're killing it with your jaws.

 

It gained improved sense of smell, size, power, bite strength. It moved from an animal that relied on packs to an animal that could be a serious threat on its own or with a small family group. Its own size made it top of the food chain, thereby removing the threat of other predators to it.

Again, I don't think you understand the point I was making. T-Rex lost all of the hunting specializations. It went from being the fast, attacking chaser to being a slow, plodding crusher.

 

And while it may not have to worry about the threat of other predators, the other predators have a distinct advantage over T-Rex, in that they were smarter, more efficient, and lethal. While T-Rex is engaging in the world's slowest dino-chase, Troadon and its pack is making mincemeat of some poor Edmontosaurus, who never even saw it coming. It seems that a much easier alternative to dottering after herbivors would be to lumber its way over to the already-grounded carcass, which it surely smells, and chase away the Troadon.

 

Well scientists who have studied the related fields for decades have not agreed on an answer so I don't think its going to be a clear cut case either way.

The complete package as I see it: A giant predator top of the food chain, fast enough to outrun the main food sources such as triceritops, jaw strength powerful enough to kill with one good bite, eyes forward for depth perception, sense of smell that would allow it to hunt in areas of poor visibility such as forests, large lung capacity to allow for chasing or fighting, a creature that wouldn't pass up a free meal if offered but powerful enough to make a meal if the countryside wasn't littered with corpses.

And the way I see it, T-Rex is not Pac Man, where all it has to do is catch up and chomp. Catching and killing prey requires a little more than just being able to keep up with your meal. The animal has no attack mechanism other than its mouth, and to even use that, it has to put itself in a chase situation, where it stands a good chance of injuring itself. A T-Rex with an injured leg is a dead T-Rex.

[Wertbag]

Apples and oranges. A shark is not a land predator. The sea is a completely different environment

Sorry I didn't mean to relate that, I was simply asking out of curiosity as to sharks sensing ability. I know they have perhaps the best smell and worst eyesight of predators but of course quite sideline from the main discussion.

 

You also greatly undermine the purpose of arms and forelimbs. They're not just for scratching but for grabbing, holding, picking yourself up when you fall down, etc. Arms are pretty handy if you're able to hold your prey as you're killing it with your jaws.

Smaller predators like velociraptor would have needed to continue attacking for a period of time to subdue a larger target. Claws would have allowed them to hang onto a target or inflict more wounds, and would therefore be quite useful. When it comes to a larger predator like T-Rex a long fight wouldn't be in the books, one bite of that size and power would be all it takes (strangely enough the pac-man idea wouldn't be too far off, similar to describing a croc hit to pac-man, one bite and its all over). If the prey turns to run it presents its back, one bite and its all over. Probably the reason for evolutionary traits that allowed herbivores to face and survive (horns, armour etc). I don't believe we can say those traits were aimed at T-Rex, but they certainly were aimed at larger predators (anything in a pack wouldn't care, just attack from behind).

If the T-Rex stayed in a family group, then just a couple of animals would be able to circle and look for the killing bite.

 

Its been a good bit of fun discussing this mystery, bit of a change over constantly debating christians and its definately been educational. Starting to get to the point where I think we've covered just about everything I can think of about the subject without repeating anything already said.

I've really got to get to a museum with a full T-Rex skeleton on display, they seem hard to find (only one in Europe that I heard about when I travelled there but didn't have time to go see it, and down here in New Zealand we don't get much more than moas).

[Mr. Neil]

Hmm... Well, Crocs wait by the water's edge, where animals have no choice but to put themselves in harm's way. It'd be interesting if a similar circumstance would exist for T-Rex. A family unit might make it possible for T-Rex to be a hunter, but I'd at least like to see some evidence of that.

 

But that's easier said than done. One of the best ways to tell if an animal species existed in a group would be from foot prints. If there are many prints all going in the same direction, then there ya go. Unfortunately, there's only one known T-Rex foot pring (yes, a single print), and no others exist, at least as of the last time I heard. I wouldn't rule it out, but it seems that to get to T-Rex as a hunter, you have to assume other things that there just isn't evidence for.

 

I also think it's good to start thinking about dinosaurs in more ways than the 2-dimensional way we've grown accustom to. There's been this naivity for decades that sharp teeth mean predator, grinding teeth mean herbivore, and dinosaur = reptile = tail drag. The dinosaurs were surely far more diverse than even we portray them now.

 

It's always more interesting to engage another scientifically literate person than a Christian, because you actually have to think. I had to delve into all sorts of little factoids I've picked up over the years. I mean, the whole thing about the dog's nose; I never thought that would be useful information in any kind of discussion.

 

Christians are just so easy to beat, because they have to employ a form of argument that is flawed from the very start. Apologetics is self-refuting, because any attempt to resolve Biblical discrepencies is an implicit admission of the existence of discrepencies; something that the Bible isn't supposed to have.

 

I used to post a little bit on a website called Movie Nitpicks. A bunch of film fantatics with way too much time on their hands would catalog mistakes found in movies. But you can also refute alleged mistakes. It's hysterical, because the way in which these people "refute" movie mistakes is identical to the methodology of the Christian apologists. It's a riot!

 

In fact, if you want to see a good parallel to Christian apologetics, look no further than Star Wars. Those movies are just loaded with contradictions, and the harmonizations are often funnier than the mistakes themselves. In fact, nothing is more Christian-like than the so-called "explanation" for Han Solo's use of the word "parsec".

[crazy-tiger]

I used to post a little bit on a website called Movie Nitpicks. A bunch of film fantatics with way too much time on their hands would catalog mistakes found in movies. But you can also refute alleged mistakes. It's hysterical, because the way in which these people "refute" movie mistakes is identical to the methodology of the Christian apologists. It's a riot!

 

In fact, if you want to see a good parallel to Christian apologetics, look no further than Star Wars. Those movies are just loaded with contradictions, and the harmonizations are often funnier than the mistakes themselves. In fact, nothing is more Christian-like than the so-called "explanation" for Han Solo's use of the word "parsec".

I'm lazy, but intrigued... gotta link?