# Could T-Rexes jump? **URL:** \ **Category:** Factual Questions\ **Created:** [January 7, 2015, 1:42am UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178 "2015-01-07T01:42:29Z")\ **Posts on this page:** 18\ **Page:** 2
**Author:** ![Ionizer](https://avatars.discourse-cdn.com/v4/letter/i/5daacb/32.png) [@Ionizer](https://boards.straightdope.com/u/Ionizer)\ **Post date:** [January 7, 2015, 3:22pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/21 "2015-01-07T15:22:22Z")
Kinda piggy-backing off of **Chronos’s** previous post, I have a curious question, please. _IF_ the T-rex had the ability to quickly move tail/head/neck upwards simultaneously, analogus to a human throwing one’s arms/shoulders upward as upward movement (jump, per se) is begun, would/could it give a _noticeable_ advantage in elevation of said jump? I am fairly ignorant of range-of-motion of anything but legs of T-rex, fwiw. Perhps there was no such range-of-motion for this, of course, from what meager details I know (fighting my own ignorance here, fwiw). I realize that T-rex’s arms would be of little impact, but neck/head/tail were considerable in mass and assumedly could contribute to upward ‘force(s)’ (right?). Would such ‘upward kinetic energy’ overcome some of limitations mentioned in some posts in this thread? Or just make a little hop into a slightly bigger hop that is still not really a ‘jump’, so to speak? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 7, 2015, 4:47pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/22 "2015-01-07T16:47:30Z")
> [@](#): > > Quoth **RNATB** : > > Having said that, the mass of an animal scales exponentially with size, No, only cubicly. An exponential scaling would be something like “every time height increases by a meter, weight doubles”. In any event, regardless of their bones, most of an animal’s weight is in flesh, which has fairly consistent density, so it’s not hard at all to get at least a very good estimate of the weight of a T. rex. And given that the actual weight will vary considerably from individual to individual, it’s not really justified to get anything better than such an estimate. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [January 7, 2015, 4:50pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/23 "2015-01-07T16:50:26Z")
Me not so good with big math wordies. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [January 7, 2015, 5:36pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/24 "2015-01-07T17:36:20Z")
Only way to know for sure:[ol] [li]Obtain Tyrannosaurus. This can be done by time travel, cloning, or finding a lost island/valley.[/li][li]Secure Tyrannosaurus in deep pit. (Be advised that due to numerous previous incidents, insurers will no longer offer liability coverage for giant prehistoric animals.)[/li][li]Dangle tasty morsel over pit. (First check your local laws for cruelty to animals/ reckless manslaughter statutes.) Lower until Tyrannosaurus can obtain morsel.[/li][/ol] ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [January 7, 2015, 5:42pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/25 "2015-01-07T17:42:26Z")
I don’t think there’s any real doubt among experts that T. Rex could run (if you think that because elephants can’t run\*, then T. Rex’s couldn’t, compare the stumpy columns of elephant legs, and then the flexed, on-the-toes, muscled legs of a T. Rex). I can’t imagine a two-legged animal that can run, but can’t get both feet off the ground. In fact, isn’t that the definition of a two-legged run? - Elephants don’t run because they don’t have to. But check out the top speed of a rhino sometime. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [January 7, 2015, 6:45pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/26 "2015-01-07T18:45:43Z")
> [@Quercus](#): > > I can’t imagine a two-legged animal that can run, but can’t get both feet off the ground. In fact, isn’t that the definition of a two-legged run? Yes, at least for humans. But if you’re 20 feet tall, you can move pretty quickly even if one foot is always on the ground. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [January 7, 2015, 8:43pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/27 "2015-01-07T20:43:43Z")
> [@AndrewL](#): > > But more importantly, could they dance? They were phenomenal at Irish dancing. ---
**Author:** ![Kenm](https://avatars.discourse-cdn.com/v4/letter/k/bc79bd/32.png) [@Kenm](https://boards.straightdope.com/u/Kenm)\ **Post date:** [January 7, 2015, 9:21pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/28 "2015-01-07T21:21:34Z")
> [@panache45](#): > > They were phenomenal at Irish dancing. And like parrots, they probably could talk if someone went back in time to teach them. “Who’s a pretty meat-eating killing-machine giant reptilian monster, then?” ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [January 7, 2015, 9:23pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/29 "2015-01-07T21:23:41Z")
> [@AndrewL](#): > > But more importantly, could they dance? the invented the Pogo. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [January 7, 2015, 9:30pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/30 "2015-01-07T21:30:16Z")
[T. Rex practicing the skill of jumping](http://www.zazzle.com/t_rex_hates_jump_rope_t_shirt-235030860231412542), seemingly with some difficulty. ---
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [January 7, 2015, 9:47pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/31 "2015-01-07T21:47:55Z")
> [@Quercus](#): > > I can’t imagine a two-legged animal that can run, but can’t get both feet off the ground. In fact, isn’t that the definition of a two-legged run? I’m imagining a T Rex [race-walking](https://www.youtube.com/watch?v=2urNVmKnEaQ). ---
**Author:** ![jimbuff314](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@jimbuff314](https://boards.straightdope.com/u/jimbuff314)\ **Post date:** [January 7, 2015, 10:50pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/32 "2015-01-07T22:50:01Z")
> [@Bumbershoot](#): > > I’m imagining a T Rex [race-walking](https://www.youtube.com/watch?v=2urNVmKnEaQ). I know you’re joking here, but guess what? > [@](#): > > Heinrich Mallison from Berlin’s Museum of Natural History would also present a theory on 2011, suggesting that Tyrannosaurus and many other dinosaurs may have achieved relatively high speeds through short rapid strides instead of the long strides employed by modern birds and mammals when running, **likening their movement to power-walking.** This, according to Mallison, would have been achievable irrespective of joint strength and lessened the need for additional muscle mass in the legs, particularly at the ankles. To support his theory, Mallison assessed the limbs of various dinosaurs and found that they were different from that of modern mammals and birds; having their stride length greatly limited by their skeletons, but also having relatively large muscles at the hindquarters.\*\* He would however find a few similarities between the musculature of dinosaurs and race-walkers; having less muscle mass in the ankles but more at the hindquarters. \*\*Mallison suggests that the differences between dinosaurs the extant mammals and birds would also have made equations to calculate speed from stride length inapplicable to dinosaurs. John Hutchinson however advised caution regarding this theory, suggesting that they must first look into dinosaur muscles to see how frequently they could have contracted From the Wiki [entry](http://en.wikipedia.org/wiki/Tyrannosaurus) on Tyrannosaurus Rex. ---
**Author:** ![slowlearner](https://avatars.discourse-cdn.com/v4/letter/s/a88e57/32.png) [@slowlearner](https://boards.straightdope.com/u/slowlearner)\ **Post date:** [January 8, 2015, 1:32am UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/33 "2015-01-08T01:32:44Z")
Hard to imagine why one would need to jump. Wonder how flexible they were, if they groomed, if a T Rex could scratch the back of his neck with a foot, or lick his balls? A mountain lion can leap from a crouch 15 or 20 feet straight up to a ledge. I’ve always just pictured a T Rex as a big mouthful of teeth charging after a meal. What if they really did dance like cranes or sing like whales? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [January 8, 2015, 2:25am UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/34 "2015-01-08T02:25:51Z")
> [@The\_Joker\_and\_the\_Thief](#): > > Since [elephants can’t jump](http://www.straightdope.com/columns/read/1462/can-elephants-jump) and have a roughly comparable weight to [t-rexes](http://www.enchantedlearning.com/subjects/dinosaurs/facts/Trex/), I think its a good as guess as any that t-rexes couldn’t jump (though there’s probably no way to answer this conclusively). I do believe that juvenile elephants have been know to jump, but not adults. [https://answers.yahoo.com/question/index?qid=20080606014106AANawEM](https://answers.yahoo.com/question/index?qid=20080606014106AANawEM) ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [January 8, 2015, 3:44am UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/35 "2015-01-08T03:44:30Z")
T-rexes got concussions when attempting cartwheels. ---
**Author:** ![RunSilent](https://avatars.discourse-cdn.com/v4/letter/r/e0b2c6/32.png) [@RunSilent](https://boards.straightdope.com/u/RunSilent)\ **Post date:** [January 9, 2015, 2:10pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/36 "2015-01-09T14:10:42Z")
I once saw Mark Bolan jump… ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [January 9, 2015, 3:04pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/37 "2015-01-09T15:04:01Z")
I posted this question on a dinosaur discussion mailing list I’m on. I got this answer from Professor Martin Baeker at Technische Universität Braunschweig: > [@](#): > > It is not too difficult to do a back-of-the-envelope estimate of this. According to our paper > > Gatesy, Stephen M., Martin Bäker, and John R. Hutchinson. “Constraint-based exclusion of limb poses for reconstructing theropod dinosaur locomotion.” Journal of Vertebrate Paleontology 29.2 (2009): 535-544. > > you can expect a max. force of a single T. rex leg of about 1.5 body > mass. You get this when the leg is still fairly straight, bent about > 50cm or so compared to a fully stretched leg. So if you assume for > simplicity that the force is constant throughout (this is an > overestimate), with a single leg you could get enough energy to jump > 75cm high; perhaps a bit more if you do some tricks with your tail, ot > if you bend down further (but too much bending is not possible). > > Jumping with both legs wuld roughly double this. > > So overall, a jump of 1meter or a bit more seems realistic, but since > the T. rex could overcome that height difference with a simple step, > there’s probably no need to run. > > In general, it should also be taken into account that a simple scaling > estimate shows that all animals should jump to roughly the same > height: muscle force scales as area (with length of animal squared), > the energy is force multiplied by length, so total energy is > proportional to l**3, as is mass. Using the potential energy equation > W=m g h, the l**3-term cancels out. > > (Of course special adaptations can change this simple picture. Please > also note that jumping height is always to be calculated relaive to > the position of the center of mass - a human jumping over a 2m bar > raises her center of mass only by a bit more than a meter.) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 9, 2015, 10:21pm UTC](https://boards.straightdope.com/t/could-t-rexes-jump/709178/38 "2015-01-09T22:21:20Z")
> [@](#): > > In general, it should also be taken into account that a simple scaling > estimate shows that all animals should jump to roughly the same > height: muscle force scales as area (with length of animal squared), > the energy is force multiplied by length, so total energy is > proportional to l**3, as is mass. Using the potential energy equation > W=m g h, the l**3-term cancels out. This is something I’ve pointed out in other threads. Note also that a flea can also jump somewhere on the order of a meter. Cats can jump perhaps two meters, from which we can conclude that they’re unusually good jumpers, but it’s still in the same ballpark. [Previous page](https://boards.straightdope.com/t/could-t-rexes-jump/709178.md?page=1)