# T-rex and impact tremors **URL:** \ **Category:** Factual Questions\ **Created:** [June 16, 2006, 1:47am UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890 "2006-06-16T01:47:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Burrido](https://avatars.discourse-cdn.com/v4/letter/b/3be4f8/32.png) [@Burrido](https://boards.straightdope.com/u/Burrido)\ **Post date:** [June 16, 2006, 1:47am UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/1 "2006-06-16T01:47:46Z")
Did T-rex (or any dinosaur) produce impact tremors when they moved about? ---
**Author:** ![Madd\_Maxx](https://avatars.discourse-cdn.com/v4/letter/m/5f9b8f/32.png) [@Madd\_Maxx](https://boards.straightdope.com/u/Madd_Maxx)\ **Post date:** [June 16, 2006, 12:05pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/2 "2006-06-16T12:05:02Z")
You were watching Discovery Channel last night too? I thought the same thing. I could maybe understand that sound effect when they are showing a close in view of a aptosaurus’ feet or trying to illustrate the relative size and bulk of larger dino’s; but every single step of any dinosaur that is larger than a dog? ---
**Author:** ![Grendel\_s\_Father](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grendel\_s\_Father](https://boards.straightdope.com/u/Grendel_s_Father)\ **Post date:** [June 16, 2006, 12:58pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/3 "2006-06-16T12:58:28Z")
I doubt it. One, the largest known _T. rex_ weighed 8 tons, max, which is about the size of a big African elephant. As far as I know, elephans, even the biggest, don’t cause impact tremors like that. Two, _T. rex_ were predators, which would evolve to be as quiet as possible so as not to startle prey. My biggst beef with a lot of the dinosaur shows on TV is that they’re always vocalizing their fool heads off, constantly roaring and such. No modern animal behaves that way, for good reason, and there’s no reason to think dinosaurs did. Except of course, roaring, thundering monsters make for better TV/movies. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [June 16, 2006, 4:41pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/4 "2006-06-16T16:41:17Z")
Yeah, Hollywood style dinosaurs annoy me too. I personally think the T Rex behaved a lot more like a modern croc than the big guy in Jurassic Park. I think they waited patiently for something big to come along, then pounced on the poor sucker. I can’t picture something that big running around through the wilderness screaming its head off. Not only would it scare away all of its food, but it would waste huge amounts of energy just moving it’s big bulky body from one place to another. Another thing that annoys me is the way they “reconstruct” what most dinosaurs look like, they all end up looking like chickens with their feathers plucked off. I have serious doubts that most of the dinosaurs looked like typical “artist renderings” that we have today. I’ve also read that according to analysis of it’s skull, T Rex didn’t have lips. Its teeth stuck out like a crock’s teeth, with no lips covering any part of them. In every dinosaur movie I’ve seen and just about every artist’s pic, the T Rex has lips. I should probably add a IANADE (dinosaur expert) here too. ---
**Author:** ![Jayrot](https://avatars.discourse-cdn.com/v4/letter/j/3ec8ea/32.png) [@Jayrot](https://boards.straightdope.com/u/Jayrot)\ **Post date:** [June 16, 2006, 5:45pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/5 "2006-06-16T17:45:55Z")
ISTR that there was some speculation at some point that the T Rex might have led more of a scavenger lifestyle. While possibly not true, it’s not hard to believe that the big guys were definitely opportunists. Decending upon a rotting bronto carcass isn’t all that glamorous. ---
**Author:** ![Cuckoorex](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@Cuckoorex](https://boards.straightdope.com/u/Cuckoorex)\ **Post date:** [June 16, 2006, 7:24pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/6 "2006-06-16T19:24:59Z")
The jury is still out on “lips” for T.rex and other therapods. Generally speaking, if they _did_ have lip-like coverings, they were almost certainly not the fleshy, muscular mammalian lips of mammals. Think more like the lip-like coverings of lizards instead. However in the case of T.rex there is such a severe overbite that a lip-like covering seems highly unlikely. I tend to depict my [T.rex in illustrations](http://pic20.picturetrail.com/VOL176/1171787/2428238/55590863.jpg) as having very minimal covering of the teeth, mostly right at the base of the teeth. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [June 16, 2006, 7:28pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/7 "2006-06-16T19:28:54Z")
Which just goes to show one should never give T. Rex any lip. He’ll take eveything connected to it as well. ---
**Author:** ![Cuckoorex](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@Cuckoorex](https://boards.straightdope.com/u/Cuckoorex)\ **Post date:** [June 16, 2006, 7:29pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/8 "2006-06-16T19:29:00Z")
Another example of [T.rex without lips.](http://pic20.picturetrail.com/VOL176/1171787/2428238/156983137.jpg) ---
**Author:** ![2MuchTrivia](https://avatars.discourse-cdn.com/v4/letter/2/e9bcb4/32.png) [@2MuchTrivia](https://boards.straightdope.com/u/2MuchTrivia)\ **Post date:** [June 16, 2006, 8:44pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/9 "2006-06-16T20:44:16Z")
I’m sure someone will either blast me, or ridicule the questions I am about to ask, but here goes: 1) Why did T-rex have such small fore-limbs? [They were not used for motive purposes and seem useless, no modern species have such seemingly useless limbs.] 2) Why 3 “fingers”? [I can’t think of one modern species that does not have 4 or 5] 3) Why could they not have hopped like kangaroos or some birds? Granted most of this has been hashed and rehashed like the aquatic ape theory, but since you all are learned and not in the least bit vindictive, your thoughts please…to the questions, not how stupid I may appear. ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [June 16, 2006, 9:02pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/10 "2006-06-16T21:02:28Z")
> [@Grendel's Father](#): > > I doubt it. One, the largest known _T. rex_ weighed 8 tons, max, which is about the size of a big African elephant. As far as I know, elephans, even the biggest, don’t cause impact tremors like that. I doubt the ground literally shook, too, but, as a nitpick, _T. Rex_ were bipedal, and were thus putting down _twice_ as much weight as a comparable quadraped with each footfall. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [June 16, 2006, 9:12pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/11 "2006-06-16T21:12:43Z")
> [@Duckster](#): > > Which just goes to show one should never give T. Rex any lip. > > He’ll take eveything connected to it as well. That T. Rex, he’s a bad mother… ---
**Author:** ![Cuckoorex](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@Cuckoorex](https://boards.straightdope.com/u/Cuckoorex)\ **Post date:** [June 16, 2006, 9:17pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/12 "2006-06-16T21:17:02Z")
> [@2MuchTrivia](#): > > 1. Why did T-rex have such small fore-limbs? [They were not used for motive purposes and seem useless, no modern species have such seemingly useless limbs.] One school of thought is that the forelimbs were so small precisely because they _weren’t_ used for anything. Maybe if they had more time to evolve, the forelimbs would have gotten stubbier and stubbier. I tend to believe that this is the case. T.rex seemed more like a shark on stilts than a grabby predator to me. Larger forelimbs may have impeded the animal in pursuing prey, and so there may have been an evolutionary advantage to the reduction in forelimb size. Other schools of thought are that the limbs may have had some use in either (a) getting up from a sleeping posture (by anchoring the torso while the back legs straightened out) though I personally doubt that this scenario is likely or (b) used like the spurs on pythons to stimulate a mate somehow, though again I find this unlikely. > [@](#): > > 1. Why 3 “fingers”? [I can’t think of one modern species that does not have 4 or 5] Technically speaking, T.rex appears to have only two digits per manus, though a recently discovered specimen shows a vestige of a third digit, which was most likely not a separate digit. In any case, see the answer to the first question; if the limbs themselves were being reduced, the digits themselves could be reduced for the same reasons. > [@](#): > > 1. Why could they not have hopped like kangaroos or some birds? Well, the larger dinosaurs would have likely suffered shattered bones from trying to hop around in the manner of anything like a kangaroo; some scientists doubt that the larger animals could jump at all. It’s kind of like saying, why can’t a sumo wrestler slam dunk? He might have stronger leg muscles than a basketball player, but he also has a lot of mass to support and the bones would have been under tremendous stress each time the animal would try to hop. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [June 16, 2006, 9:50pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/13 "2006-06-16T21:50:47Z")
> [@Cuckoorex](#): > > The jury is still out on “lips” for T.rex and other therapods. As I recall, Robert Bakker was the one who first propsed lips for _T. rex_ and others, based on holes in the jaw line which he interpreted as being for blood vessels which would supply said lips. His reconstructions of be-lipped tyrannosaurs (and apatosaurs) look rather…odd. Just about all the reconstructions I’ve seen are as **Cuckoorex** draws them, so I’m not sure the lipped version has ever really been accepted as mainstream. As for tremors, I wouldn’t doubt that a herd could produce them. Single animals…probably not so much. ---
**Author:** ![2MuchTrivia](https://avatars.discourse-cdn.com/v4/letter/2/e9bcb4/32.png) [@2MuchTrivia](https://boards.straightdope.com/u/2MuchTrivia)\ **Post date:** [June 16, 2006, 10:01pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/14 "2006-06-16T22:01:13Z")
Thank you **Cuckoorex** I can see your points, but is there a 2 digited animal existing today? [Just a weird question that always bugged me]. What bone evidence says they were more like sumo’s than birds or kangaroos? ---
**Author:** ![Evil\_Captor](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@Evil\_Captor](https://boards.straightdope.com/u/Evil_Captor)\ **Post date:** [June 16, 2006, 10:40pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/15 "2006-06-16T22:40:05Z")
> [@2MuchTrivia](#): > > I’m sure someone will either blast me, or ridicule the questions I am about to ask, but here goes: 1) Why did T-rex have such small fore-limbs? [They were not used for motive purposes and seem useless, no modern species have such seemingly useless limbs.] 2) Why 3 “fingers”? [I can’t think of one modern species that does not have 4 or 5] 3) Why could they not have hopped like kangaroos or some birds? > Granted most of this has been hashed and rehashed like the aquatic ape theory, but since you all are learned and not in the least bit vindictive, your thoughts please…to the questions, not how stupid I may appear. My theory, which is noted for being adopted by absolutely no one, is that T-rex’s tiny forelimbs were tiny because they were used strictly to clean the teeth of other, smaller predators. The size and elaborate dentition of T-rex was purely defensive, to prevent the other predators from eating them after they cleaned the predator’s teeth. In short, T-rex occupied the same ecological niche as some species of wrasse do in coral reefs. ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [June 16, 2006, 10:56pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/16 "2006-06-16T22:56:12Z")
So, crocs don’t have lips, right? But they live in the water (mostly). If the T-Rex had no lips, wouldn’t his mouth dry out? Or did he secrete copious amounts of saliva? Or is the question flawed somehow because of something basic I’m missing? I have no opinion on the lips no lips debate, just asking a question that came up while reading this. ---
**Author:** ![Burrido](https://avatars.discourse-cdn.com/v4/letter/b/3be4f8/32.png) [@Burrido](https://boards.straightdope.com/u/Burrido)\ **Post date:** [June 16, 2006, 11:16pm UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/17 "2006-06-16T23:16:30Z")
> [@Cuckoorex](#): > > One school of thought is that the forelimbs were so small precisely because they _weren’t_ used for anything. But why were they so strong then? Sue was said to be have been able to lift 1200 pounds with one arm. Or is just weak relative to it’s size? ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [June 17, 2006, 12:13am UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/18 "2006-06-17T00:13:02Z")
I saw a documentary on one of the channels. A guy had been able to create dinosaurs from DNA extracted from insects inside amber. Then he cloned them. The TRex on that documentary caused impact tremors. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [June 17, 2006, 12:38am UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/19 "2006-06-17T00:38:12Z")
> [@Burrido](#): > > But why were they so strong then? Sue was said to be have been able to lift 1200 pounds with one arm. Or is just weak relative to it’s size? We can’t really say for certain that they were _that_ strong. The arms were certainly small _for the size of the animal_, but in terms of absolute size, they were typically about as long as an adult human’s arms, and probably at least as well muscled. This would imply that they weren’t useless, but their uses would have been relatively limited. But that doesn’t mean they were _for_ any specific function, any more than ours are. To put it somewhat glibly, they were used for whatever use they could be put to. ---
**Author:** ![lizardling](https://avatars.discourse-cdn.com/v4/letter/l/f4b2a3/32.png) [@lizardling](https://boards.straightdope.com/u/lizardling)\ **Post date:** [June 17, 2006, 2:50am UTC](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890/20 "2006-06-17T02:50:37Z")
> [@2MuchTrivia](#): > > Thank you **Cuckoorex** I can see your points, but is there a 2 digited animal existing today? [Just a weird question that always bugged me]. What bone evidence says they were more like sumo’s than birds or kangaroos? Ostriches? The digits are on the feet, but AFAIK ostriches don’t have the extra toe that other birds do for gripping. [Next page](https://boards.straightdope.com/t/t-rex-and-impact-tremors/360890.md?page=2)