T-Rex Predator or Scavenger?

ive also seen the show. the sharp teeth make you think he is one nasty monster. but the thing is comparison of his thigh and leg bone show he would be very slow and his stubby short arms would make it hard to get up if he fell.so i would say he would attack slow prey but other than that he was a wimp.

It goes without question that any carnivorous predator will eat carrion if it fits their appetite. No doubt all predators like free meals. Hunting always carries a degree of risk along with the expenditure of energy in search of energy.

As far as the T-rex being too loud to stalk prey, well all predators no matter how large are stealthy or posess knowledge / instinct on how to be stealthy in their environment when they are hunting. No one could possibly say that a Siberian tiger, a salt-water crocodile is not stealthy, yet they are some of the largest land predators. Consequently each one eats carrion when it can, too.

All animals are defined by their environment and since T-rex was alive in a world we are unfamiliar with, so are the details of the T-rex's life. However any carnivore the size of a T-rex would not be searching for dead animals, it would be making animals dead! There just wouldn't be enough carrion in the environment to sustain a body like that, and it wouldn't be such a huge animal with jaws and teeth of that size if it didn't have to use them. Nature is very conservative and the design of an animal is very efficient.

There are many stereotypes about dinosaurs and no doubt some of the facts we've established are based on conjecture and are untrue, but the case of T-rex being a pure carrion eater seems so ridiculous that it sounds like a originator of the idea is simply trying to make a wild case for some recognition.

Carrion-eaters or scavengers that a purely scavengers are actually somewhat rare because all omnivores / carnivores are always searching for the 'free meal' of carrion. And when the scavenger finds the free meal its in constant danger of a larger animal coming for the same thing. Note that the biggest carrion-eater are birds like the vulture, and the reason they are able to sustain mostly off carrion is because they have command of the air and are constantly searching for it. If you ever see vultures in the sky, lie down on the ground face-up and lay still. They will start circling within minutes.

So, to say a 5 - 7 ton land animal that's nothing but legs and mouth was stalking around waiting for a hydrosaur two-thirds its size to die, doesn't make much sense simply by looking at the animals in scavenger niches today.

Originally posted by phantompatriot
ive also seen the show. the sharp teeth make you think he is one nasty monster. but the thing is comparison of his thigh and leg bone show he would be very slow and his stubby short arms would make it hard to get up if he fell.so i would say he would attack slow prey but other than that he was a wimp.

Then again, have you ever seen a bird walking around tripping and falling? And how often do you see lions running fast? They can run fast but do so for very good reasons, like ambushing an animal or attacking. They don't just go jogging to stay in shape. Ostriches and people can stand up without using arms. T-rex, if it fell for some reason, would only have to tuck his legs, roll on his belly and stand.

Originally posted by taibunsuu
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There are many stereotypes about dinosaurs and no doubt some of the facts we've established are based on conjecture and are untrue, but the case of T-rex being a pure carrion eater seems so ridiculous that it sounds like a originator of the idea is simply trying to make a wild case for some recognition.

Thats the weird part the Originater of this idea is one of the worlds best known and respected paleontologist Jack Horner. Horner consulted on the movies Jurassic Park and The Lost World (and who admits to rooting for the dinosaurs) He was even the model for the scientist, Alan Grant in the movie, Jurassic Park.

Horner has also contradicted accepted theory by hypothesizing that dinosaurs were warm-blooded and could shift their metabolic rates as they grew older, which may account for their tremendous size.

Horner's own most startling discoveries and theories include:

* a bonebed containing more than 10,000 duckbill dinosaurs, which showed that dinos were most likely social animals that traveled in herds;

* nests containing baby dinosaurs and dinosaur eggs, which showed that adults raised and probably fed their young;

* a rare, nearly-complete Tyrannosaurus Rex skeleton, which helped Horner conclude that this behemoth was actually a scavenger, not the fearsome predator it's been miscast as in popular culture.

* the world's first dinosaur embryos, which showed that dino skeletons grew like those of birds

Explaining how he came to challenge many long-held beliefs, Horner says, "Rethinking how we do science, and thinking about science as a process rather than a body of knowledge is very important.

I agree with his view on science the way we should view it. But I find myself on the side of another famous paleontologist Bob Bakker on the T-Rex subject. Bob Bakker was the model of the guy in Jurassic Park 2 that runs out of the cave and is eaten by the T-Rex. I think T-Rex chomped the wrong guy

I still have the lots of respect for Jake Horner but I have to disagree with him.

Explaining how he came to challenge many long-held beliefs, Horner says, "Rethinking how we do science, and thinking about science as a process rather than a body of knowledge is very important.

Hmm, that's a really nice bit of info in a great response - good example why I like these boards.

I figured it was some upstart type guy but this guy is obviously very knowledgable about his subject. Of course people romanticize things of great power and it would be more interesting if T-rex were a predator instead of an oversized vulture, so that could influence the popular image of T-rex, too.

As far as those movies, I wonder if an adult T-rex would even care to eat a person. A 200-pound man is to a T-rex what a 1.5 pound squirrel is to the man. I'd guess that as long as the T-rex isn't particularly hungry a human would be pretty safe near one.

Hmmm, this makes me want to see that new movie from Bradbury's 'A Sound of Thunder' story.

I remember seeing on TV and also reading about this subject.

To me it would seem pure common sense that the T Rex was not a hunter. It had no way of grabbing its pray due to its short arms. Also the fact that if it fell over it would have extreme difficulty standing again which would therefore make it vunerable to predators.

Its size also supports this, as many of todays scavengers rely on size to scare awy other scavengers.

On a funny note, I remember a show with Eddie Izzard where he suggested(in a comical way) that the T-Rex had short close together arms so it could play the piano and deal cards more easily.

Hello, I am a Paleontologist who works for Morrison Natural History Museum, I stumbled on this topic and thought I would give my two cents.

First off T.rex was most definently capable (and did) hunt its own food.
The evidence of Leg proportions is incorrect. True, the proportions were not that of an animal that is a long distance runner (a horse), but closer to another animal (rhino). The big question when looking at the legs is the muscle attachments (you can see muscle scars where the muscle attaches to bone) T. rex has HUGE attachments very similar to a rhino. Incidently rhinos may run faster than horses, but not for as long. Also recent discoveries from the Black Hills Institute, have shown a complete stride of T.rex with the Toes dug in (ie deeper) indicating the animal was running. Calculations show it would be moving at 45mph.

The large olfactory sense in the brain is also biased. Most animals, including sharks, dogs, lions, hyenas, etc. have excellent senses of smell and use them to help them navigate large distances. Why shouldn't it be the same for dinosaurs. When you weigh 5 tons, you need to find your next meal fast.

T.rex had a brain the size of a bannana, which relative to its body size isn't great, but good enough. They relied on instinct, however a close relative of rex, Troodon (looked very much like a velociraptor, real one not like JP[ironically closer related to T.rex than the "raptors"]), is the smartest dinosaur (similar proportion as an ostrich).

In regards to pack behavior, there is mounting evidence that at times they would form small packs (probably as the young are getting ready to leave the group). Phillip Currie recently rediscovered a bone bed showing about 5-6 albertosaurs (VERY close relative of rex, only a tiny bit smaller) died together in a flash flood. Not a trap. Also Sue's broken leg healed, hard to catch food, or even move to a dead carcass with a broken leg. This implies another animal helped get food.

As far a rex standing up straight. It could have if it wanted to, no bones would have broke. Iguanodon was the animal that needed its tail broken, that is due to ossified tendons called myomers. the evidence we have that it carried itself the way we now think of it, is no tail drag marks in the tracks, and its weight is further back on its foot than we originally thought.

As far as balance, Theropods actually have the best design for a bipedal animal that ever evolved. it is exceptionally well balanced, look at ostriches and emus. Humans on the other hand have a horrible design (we wear out after 30 years, bad knees bad back, etc.). Our design fights gravity, theropods used gravity to their advantage.

As far as things we won't learn:

T. Rex wsan't like a chameleon, it actually had feathers (yes, rex was fluffy). we see this based on the size of small openings for blood vessels and nerve endings called foramen, they are huge on rex's skull.

T.rex wasn't venomous, he didn't have the right teeth for it. Venom is injected through hollow teeth, all of rex's teeth were solid.

Finally theropods (including dilophosaurus) could Never ever spit. They didn't have the lips for it. based on foramen we have distinguished that rex and other theropods have lips like a croc. Prehensile lips are necessary to spit (like us, or a camel). We build up pressure behind our lips and *ptooey* we spit. They couldn't build up the pressure. BTW "spitting" cobras don't really spit either, they just have a squirt gun like venom sack (which is far more interesting). Though sauropods may have been able to.

WE actually do find soft body fossils, though very rare (in fact we had FOUR mummy dinosaurs. only 2 now, the other two are at the bottom of the atlantic, sunk during WWII.) Animals with cartelage can't live on dry land, not enough support, so they die under water and if the conditions are just right we do get soft body fossils, including squid (very cool to look at) and jellyfish (sadly disappointing).

As far as Horner, he has done interesting stuff but you have attributed too much to him.

Bakker proposed the warm blooded metablosim in the 60s, before Horner.

Grant was a composite character of Horner and Bakker (though if you read the books he is more like Bob, which really makes since when you meet them).

the T.rex in question was found by Sue Hendrickson and Peter Larson with the Black Hills institute. Horner has found parts of one, but it was far from complete.

Finally, Horner seriously hates T.rex. No joke. You get to talking with him and he will swear about rex. I think this whole argument is an attempt at character assasination.

IMHO: T. rex was both, mainly because that is what we see today. Once you get big enough, you don't have to hunt for your food. However, T.rex was definently something that could have hunted its entire life, unless illness or injury prevented it.

Bug Einme Thanks for a very informative reply I love to learn about dinosaurs as a hobby its been a life long love for me. Its great to get feedback from a real paleontologists, It reminds me how much of a novice I really am.

About the T.rex found in part by Sue Hendrickson I should have picked up on that since I believe they named that T-rex Sue, which would make sense.

As for the feathers on T-rex its hard to get over the preconcived picture we have of Rex. I tend to think that if T-rex did indeed have feathers that they would not extend all the way to his head. I think it would be likely to have a feather pattern like a vulture, a bald head and a feathered body. Since I think the T-rex was a messy eater having your feathers get all bloodly would not be ideal and a pain for it to clean. I could be wrong about this and I have no proof but It just seems right to me.

One thinG I wanted to ask you about the venom issue. I wasnt really thinking so much off something like snake vemon with hollow teeth. But really more along the line of a infectious like that of the Komodo Dragon. Venom might not have been the best word to use in hindsight.Surley many meat eating dinosaurs mouths would have been breeding grounds for all types of nasty bacteria. Do you think its possible some carnivorous dinosaurs might have had something like the saliva of the Komodo dragon? Not like we will be ever able to prove it though.

I really like they way you described T-rex like a Rhino great example. I often think of the crocodile if we just had bones to go on people would think that it would be as slow as a snail on land with those stubby legs. But in reality the crocodile can make burst of speed that can be just as fast as a horse in short distances. The T-rex might not have been a marathon runner but could have been very quick in burst of speed. Really you only to have be as fat as your prey anyway.

About the Grant character I never really read the book I was just going on what they said on the making of the movie. The paleontologist in the second movie working for the bad guys (Genetech I think) really looked alot like Bakker. I have seen Bakker refer to that guy as modeled after him, he didnt seem to happy that they had him get eaten by the T-rex.

If you really meet Bakker that is so cool, He seems like a nice guy on TV.

"Horner seriously hates T.rex" It really does seem that way on TV. It really seems like most paleontologists share a view like yours and Bakker on the subject. Then we have Horner pretty much on his own advocating that T-rex was pure scavenger.

[edit on 6-10-2004 by ShadowXIX]

Originally posted by ShadowXIX
Bug Einme Thanks for a very informative reply

I love to learn about dinosaurs as a hobby its been a life long love for me. Its great to get feedback from a real paleontologists, It reminds me how much of a novice I really am.

As for the feathers on T-rex its hard to get over the preconcived picture we have of Rex. I tend to think that if T-rex did indeed have feathers that they would not extend all the way to his head. I think it would be likely to have a feather pattern like a vulture, a bald head and a feathered body. Since I think the T-rex was a messy eater having your feathers get all bloodly would not be ideal and a pain for it to clean. I could be wrong about this and I have no proof but It just seems right to me.

I'd like to support those thanks, that was quite a good post. Also I can't quite picture the feathers on T-Rex, I keep seeing a big tough dinosaur wearing a feather boa. It's difficult to imagine feathers on an animal without wings, since even flightless birds have wings along with their feathers.

it was a predator and scavenger,..................

[edit on 6-10-2004 by DarkSide]

What about either a septic bite or a bite like a Gila monster ?

Originally posted by Bug Einme
Hello, I am a Paleontologist who works for Morrison Natural History Museum, I stumbled on this topic and thought I would give my two cents.

First off T.rex was most definently capable (and did) hunt its own food.
The evidence of Leg proportions is incorrect. True, the proportions were not that of an animal that is a long distance runner (a horse), but closer to another animal (rhino). The big question when looking at the legs is the muscle attachments (you can see muscle scars where the muscle attaches to bone) T. rex has HUGE attachments very similar to a rhino. Incidently rhinos may run faster than horses, but not for as long. Also recent discoveries from the Black Hills Institute, have shown a complete stride of T.rex with the Toes dug in (ie deeper) indicating the animal was running. Calculations show it would be moving at 45mph.

The large olfactory sense in the brain is also biased. Most animals, including sharks, dogs, lions, hyenas, etc. have excellent senses of smell and use them to help them navigate large distances. Why shouldn't it be the same for dinosaurs. When you weigh 5 tons, you need to find your next meal fast.

T.rex had a brain the size of a bannana, which relative to its body size isn't great, but good enough. They relied on instinct, however a close relative of rex, Troodon (looked very much like a velociraptor, real one not like JP[ironically closer related to T.rex than the "raptors"]), is the smartest dinosaur (similar proportion as an ostrich).

In regards to pack behavior, there is mounting evidence that at times they would form small packs (probably as the young are getting ready to leave the group). Phillip Currie recently rediscovered a bone bed showing about 5-6 albertosaurs (VERY close relative of rex, only a tiny bit smaller) died together in a flash flood. Not a trap. Also Sue's broken leg healed, hard to catch food, or even move to a dead carcass with a broken leg. This implies another animal helped get food.

As far a rex standing up straight. It could have if it wanted to, no bones would have broke. Iguanodon was the animal that needed its tail broken, that is due to ossified tendons called myomers. the evidence we have that it carried itself the way we now think of it, is no tail drag marks in the tracks, and its weight is further back on its foot than we originally thought.

As far as balance, Theropods actually have the best design for a bipedal animal that ever evolved. it is exceptionally well balanced, look at ostriches and emus. Humans on the other hand have a horrible design (we wear out after 30 years, bad knees bad back, etc.). Our design fights gravity, theropods used gravity to their advantage.

As far as things we won't learn:

T. Rex wsan't like a chameleon, it actually had feathers (yes, rex was fluffy). we see this based on the size of small openings for blood vessels and nerve endings called foramen, they are huge on rex's skull.

T.rex wasn't venomous, he didn't have the right teeth for it. Venom is injected through hollow teeth, all of rex's teeth were solid.

Finally theropods (including dilophosaurus) could Never ever spit. They didn't have the lips for it. based on foramen we have distinguished that rex and other theropods have lips like a croc. Prehensile lips are necessary to spit (like us, or a camel). We build up pressure behind our lips and *ptooey* we spit. They couldn't build up the pressure. BTW "spitting" cobras don't really spit either, they just have a squirt gun like venom sack (which is far more interesting). Though sauropods may have been able to.

WE actually do find soft body fossils, though very rare (in fact we had FOUR mummy dinosaurs. only 2 now, the other two are at the bottom of the atlantic, sunk during WWII.) Animals with cartelage can't live on dry land, not enough support, so they die under water and if the conditions are just right we do get soft body fossils, including squid (very cool to look at) and jellyfish (sadly disappointing).

As far as Horner, he has done interesting stuff but you have attributed too much to him.

Bakker proposed the warm blooded metablosim in the 60s, before Horner.

Grant was a composite character of Horner and Bakker (though if you read the books he is more like Bob, which really makes since when you meet them).

the T.rex in question was found by Sue Hendrickson and Peter Larson with the Black Hills institute. Horner has found parts of one, but it was far from complete.

Finally, Horner seriously hates T.rex. No joke. You get to talking with him and he will swear about rex. I think this whole argument is an attempt at character assasination.

IMHO: T. rex was both, mainly because that is what we see today. Once you get big enough, you don't have to hunt for your food. However, T.rex was definently something that could have hunted its entire life, unless illness or injury prevented it.

The septic bite is an interesting idea. But, considering the massive bite force and the large area that a T-rex could remove in one bite, that alone would be sufficient to cripple a prey animal to the point that it wouldn't get very far before it would succumb. I think the arguements (predator/scavenger) are kind of irrelevant. It was a big meat eater, and a successful animal whose lineage spanned many millions of years. Scavenging or not I wouldn't wanna' meet that critter anywhere.

Since a couple of us touched on Sue.... The story of this dino is rather remarkable, and I'd encourage those interested to do a Google, and see what you find...

She was a very long-lived female T-Rex and the largest found (if I recall correctly). Things such as bone fusions, etc. from old injuries really help you get a feel for how Sue lived, and was quite the Queen of monsters...