# Why do reptiles, dinosaurs, etc. randomly roar? **URL:** \ **Category:** Factual Questions\ **Created:** [March 8, 2007, 9:13pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162 "2007-03-08T21:13:10Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![Webner](https://avatars.discourse-cdn.com/v4/letter/w/0ea827/32.png) [@Webner](https://boards.straightdope.com/u/Webner)\ **Post date:** [March 8, 2007, 9:13pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/1 "2007-03-08T21:13:10Z")
So lately I’ve been enjoying BBC’s _Walking With Dinosaurs_ and _Walking With Monsters_ series, both of which I heartily recommend to anyone interested in learning about evolutionary history but too lazy to pick up a book about it. One thing I noticed in these masterworks is that every time you see a herd of dinosaurs grazing, or doing pretty much anything, every few seconds one of them picks up its head and roars randomly. Or an amphibian roars as he peeks around a tree, waiting for a mother to drop her guard so that he can snatch her egg. They roar in pretty much any situation, even if, as in the last one I mentioned, it might blow their cover. I always thought the main purpose of a roar was to frighten another creature, establish a mating area, etc. This seems like a pretty big waste of energy, and it got me wondering if the computer animators just put this in to make the animals seem more alive. I haven’t seen many nature documentaries so I don’t know if animals do this in real life. So, is this an accurate depiction of animal/dinosaur/reptile behavior, and if it is, why the constant roaring? ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [March 8, 2007, 9:16pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/2 "2007-03-08T21:16:16Z")
I can’t speak (or roar) for any contemporary reptiles, but any roaring you hear from a dinosaur came primarily from the animator’s imagination. So far, no colossal fossil sounds have been found. ---
**Author:** ![FatBaldGuy](https://avatars.discourse-cdn.com/v4/letter/f/ecd19e/32.png) [@FatBaldGuy](https://boards.straightdope.com/u/FatBaldGuy)\ **Post date:** [March 8, 2007, 9:18pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/3 "2007-03-08T21:18:08Z")
I doubt that anyone on this board (or anywhere else) will be able to give you an authoritative answer about how dinosaurs roared/did not roar in their native environment. If anyone claims to know the answer, I would be extremely suspicious of their credentials. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 8, 2007, 9:23pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/4 "2007-03-08T21:23:13Z")
We have a good idea of what at least [one species](http://www.exn.ca/Html/Templates/topicpage.cfm?ID=19971208-07&Topic=Dinosaur) may have sounded like. Nothing probative, of course, but it’s something. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 8, 2007, 9:35pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/5 "2007-03-08T21:35:15Z")
[QUOTE=FatBaldGuy] I doubt that anyone on this board (or anywhere else) will be able to give you an authoritative answer about how dinosaurs roared/did not roar in their native environment. If anyone claims to know the answer, I would be extremely suspicious of their credentials. [/QUOTE] While we may not know the specifics of dinosaur behavior, we can certainly draw inferences based on the behavior of present day animals of (presumed) similar ecology. And the behavior described in the OP is not typical of modern animals. Calling is generally restricted to contexts of attracting a mate, maintaining social contacts, and aggression against conspecifics or other threats. Random roaring as described in the OP is purely a convention adopted by computer animators, presumably to make the animals seem more lifelike. There is no reason to suppose these animals behaved this way, and considerable reason to believe they would not have. This is just one of the things that irritates me about some of the “Walking with Dinosaurs” type shows. ---
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [March 8, 2007, 9:39pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/6 "2007-03-08T21:39:02Z")
[QUOTE=FatBaldGuy] I doubt that anyone on this board (or anywhere else) will be able to give you an authoritative answer about how dinosaurs roared/did not roar in their native environment. [/QUOTE] An authoritative answer, no … but I’d be mildly surprised if it was widely thought that _no_ educated insight could be gained from observations of modern reptiles and birds. ---
**Author:** ![SiXSwordS](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@SiXSwordS](https://boards.straightdope.com/u/SiXSwordS)\ **Post date:** [March 8, 2007, 9:58pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/7 "2007-03-08T21:58:18Z")
[QUOTE=Webner] \*t got me wondering if the computer animators just put this in to make the animals seem more alive. I haven’t seen many nature documentaries so I don’t know if animals do this in real life. [/QUOTE] Even IRL documentaries use sound that is added in post-production. (Sometimes I notice an underwater scene with sounds of water sloshing around mixed in with the obligatory tssshrt… gurgl, gurgl, gurgle sound of the scuba gear.) Sometimes there is an effort to make the sounds natural and other times it’s more like [Foley](http://www.straightdope.com/classics/a5_012.html) work in mainstream movies. In the case of dinosaurs, I think it’s safe to say that the post-production team is trying to add to the illusion rather than trying to accurately replicate dinosaur behavior. ---
**Author:** ![daffyduck](https://avatars.discourse-cdn.com/v4/letter/d/ec9cab/32.png) [@daffyduck](https://boards.straightdope.com/u/daffyduck)\ **Post date:** [March 8, 2007, 10:41pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/8 "2007-03-08T22:41:48Z")
[QUOTE=bordelond] An authoritative answer, no … but I’d be mildly surprised if it was widely thought that _no_ educated insight could be gained from observations of modern reptiles and birds. [/QUOTE] In that case, dinosaurs never roared. Modern reptiles hiss. As mentioned, fossils with “sound chambers” have been found, so the story is more complicated. Movie dinosaurs roar because it’s entertaining and “Walking with Dinosaurs” is meant to entertain. The “science” is just for fun. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 8, 2007, 10:59pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/9 "2007-03-08T22:59:12Z")
[QUOTE=daffyduck] In that case, dinosaurs never roared. Modern reptiles hiss. As mentioned, fossils with “sound chambers” have been found, so the story is more complicated. Movie dinosaurs roar because it’s entertaining and “Walking with Dinosaurs” is meant to entertain. The “science” is just for fun. [/QUOTE] The closest living relatives of dinosaurs, birds and crocodilians, are both quite vocal. Alligators roar, and some birds make very loud noises. Among more distantly related groups, some lizards croak or have other kinds of calls besides hisses. Like their modern relatives, dinosaurs were probably vocal, and some probably did roar. (Large animals, as might be expected, typically make much louder sounds than small ones.) The fact that these documentaries show them roaring is not the inaccurate part, it’s that they roar apparently at random rather than in particular behavioral contexts. ---
**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:** [March 8, 2007, 11:16pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/10 "2007-03-08T23:16:24Z")
Some of my favorite dinosaur-related quotes comes from this site compiled by a student of predatory dinosaur expert Tom Holtz. > **[Celebrating 50 years! | Department of Geological, Environmental, and...](https://www.geol.umd.edu/~tholtz/G104/50things.htm)** On a scene in Jurassic Park, Holtz said: > [@](#): > > So it gets up to Newman and the SCREAMS at him and puffs out his frills… not very good predatory behavior… The whole random roaring issue is probably my biggest pet peeve about paleontology-based entertainment, especially in shows that present themselves as factually accurate. Absolutely no modern animals behave like that, and there’s no reason to think dinosaurs would. It just helps make them seem more like movie monsters than real, living animals. I can think of numerous examples in the Walking With Dinosaurs series, When Dinosaurs Roamed America, etc., where predators are screaming their fool heads of while chasing prey! What exactly would this accomplish, but maybe scare the prey into running faster? Unless I’m mistaken, Walking With Monsters had not only primitive tertrapods/amphibians (only the frogs are vocal, as far as I know, and they weren’t frog relatives) vocalizing, but _arthropods_, including a giant millipede and a spider, making almost constant vocal sound. I’ve squished a few spiders in my day, and only in the movies have I heard any let out a high-pitched squeal. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [March 8, 2007, 11:21pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/11 "2007-03-08T23:21:17Z")
Well, if you watch documentary films about real animals, they’ll show the animals engaging in “interesting” behavior. If you just sat in a land rover and watched a pride of lions, most of the time they’d lie there sleeping or gazing into the middle distance. Pretty boring after 10 straight hours. So the documentary might show a few minutes of sleeping lions, but they’re going to throw out 99% of their footage that just shows lions sleeping, and show the footage of lions doing interesting things like hunting, fighting, eating, mating, playing, or…roaring. So any show about lions is going to show a roaring lion even though 99.99% of a lions time is spent not roaring. I agree that it’s unrealistic for animals to just randomly roar for no discernable reason. So a “Walking with Lions” pseudodocumentary wouldn’t show lions ambling along the CGI savannah, roaring, then ambling on again, because we know that lions don’t do that. They roar at each other in threat displays, they roar to intimidate hyeanas, but they don’t roar randomly. So any show where dinosaurs are munching away on plants and suddenly rear up and roar is kind of silly. Modern animals vocalize for a reason, dinosaurs should do the same. But note that there are some species that vocalize a LOT. If you’re around some birds it’s just a constant barrage of noise. But other birds are quiet. It wouldn’t surprise me if some social dinosaur species were quite the chatterboxes. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [March 8, 2007, 11:25pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/12 "2007-03-08T23:25:46Z")
Well, to be fair to the Jurassic Park scene, the Dilophosaurus isn’t engaging in predatory behavior but threat behavior. He doesn’t act like he sees Newman as prey but as a threat. He puffs out his frills and hisses precisely to make himself scarier. Animals that attack humans often vocalize because they are attacking the humans out of fear rather than hunger. Not that we should expect a Dilophosaurus to be afraid of a human. ---
**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:** [March 9, 2007, 1:44am UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/13 "2007-03-09T01:44:22Z")
[QUOTE=Lemur866] Not that we should expect a Dilophosaurus to be afraid of a human. [/QUOTE] Not that we should expect a _Dilophosaurus_ to fit inside a Jeep Wrangler, either. At any rate, the only real studies of dinosaur vocalization have been done with lambeosaurine dinosaurs, such as _Parasaurolophus_, which **Q.E.D.** mentioned (some minor studies have also been done with respect to ankylosaur vocalizations). And even then, those studies were largely concerned with how the critters being examined might have sounded, rather than how they might have behaved. So under what circumstances, if any, dinosaurs might have bellowed and/or roared remains purely within the realm of speculation, as has been mentioned. And, as has also been mentioned, based on modern analogues, they probably didn’t do so with anywhere near the frequency that one would gather from watching fake natural history documentaries, such as the _Walking With_ series. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [March 9, 2007, 1:49am UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/14 "2007-03-09T01:49:24Z")
[QUOTE=Webner] So, . . . why the constant roaring? [/QUOTE] Foley editors have bills, too. ---
**Author:** ![Khampelf](https://avatars.discourse-cdn.com/v4/letter/k/8e7dd6/32.png) [@Khampelf](https://boards.straightdope.com/u/Khampelf)\ **Post date:** [March 9, 2007, 8:40pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/15 "2007-03-09T20:40:24Z")
My subjects are silent on the topic. SLK ---
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [March 9, 2007, 9:48pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/16 "2007-03-09T21:48:42Z")
[QUOTE=SiXSwordS] Even IRL documentaries use sound that is added in post-production. (Sometimes I notice an underwater scene with sounds of water sloshing around mixed in with the obligatory tssshrt… gurgl, gurgl, gurgle sound of the scuba gear.)… [/QUOTE] I’ve taken underwater video footage and the camera’s microphone picked up the regulator noise, although my face _was_ pressed against the rear plate of the housing. When editing it later I left the noise in at half volume under the music. On the original topic… As an animator myself, I personally wouldn’t have a dinosaur roar without a reason unless directed to do so. On the _Walking_ series, though, I know the commentary is absolutely dreadful, so I might do it just to drown it out and keep the audience awake. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [March 11, 2007, 10:14am UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/17 "2007-03-11T10:14:38Z")
[QUOTE=Colibri] And the behavior described in the OP is not typical of modern animals. Calling is generally restricted to contexts of attracting a mate, maintaining social contacts, and aggression against conspecifics or other threats. [/QUOTE] Hang on. The OP describes how “you see a herd of dinosaurs grazing, or doing pretty much anything, every few seconds one of them picks up its head and roars randomly.”. That sort of behaviour, especially for grazing animals, is typical. If you watch a herd of bison or wildebeest or even cattle grazing it is expected that one will lift its head up and call, seemingly at random. Of course it isn’t actually random, they are usually calling to ascertain the location of their calves, but in my experience any herd of grazing animals will typically produce at least one call every 15 minutes or so. If the herd is travelling rather than grazing the calls become almost constant and by all accounts the sound from the calls of a migrating wildebeest herd is quite deafening. Then we can look at the best analogues of the behaviour of dinsoaurs: birds. A herd of grazing birds such as geese call almost incessantly. Hell, anyone who has ever owned free range chickens knows that they keep in constant contact with each other by calling. So to say that dinosaurs wouldn’t behave like that is inaccurate. Mothers communicating with their calves, dominance displays or simply herd bonding could all readily produce situations where the animals randomly roar. > [@Grendel's Father](#): > > where predators are screaming their fool heads of while chasing prey! What exactly would this accomplish, but maybe scare the prey into running faster? Once again if birds are used as the piont of comparison this is pretty normal behaviour. A chicken chasing after prey will call almost incessantly. Many birds of prey call as they chase their prey. Many birds such as shrikes also call as they chase prey. Why do they do this? I hadn’t really thought about it but I guess the idea is to frighten the prey into making a mistake, although with chickens it may also assist in communal hunting. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 11, 2007, 7:33pm UTC](https://boards.straightdope.com/t/why-do-reptiles-dinosaurs-etc-randomly-roar/395162/18 "2007-03-11T19:33:19Z")
[QUOTE=Blake] Hang on. The OP describes how “you see a herd of dinosaurs grazing, or doing pretty much anything, every few seconds one of them picks up its head and roars randomly.”. That sort of behaviour, especially for grazing animals, is typical. If you watch a herd of bison or wildebeest or even cattle grazing it is expected that one will lift its head up and call, seemingly at random. Of course it isn’t actually random, they are usually calling to ascertain the location of their calves, but in my experience any herd of grazing animals will typically produce at least one call every 15 minutes or so. If the herd is travelling rather than grazing the calls become almost constant and by all accounts the sound from the calls of a migrating wildebeest herd is quite deafening. [/quote] I don’t think we are necessarily in disagreement here. The OP says “every few seconds”; you say an individual in a herd may call “every 15 minutes or so.” In my experience with herd animals in Africa (Cape buffalo, elephants, zebra, antelope), India (elephants, gaur), North America (elk, other deer) and the neotropics (peccaries, guanaco, vicuna) members of a _grazing_ or feeding herd call quite infrequently if at all. Therefore the depiction of herd animals calling every few seconds while grazing would be inaccurate. I agree that a travelling herd will produce contact calls frequently. But these are usually bleating or lowing calls, and wouldn’t be described as “roars.” It’s true herd animals bellow loadly when frightened and the herd is fleeing a predator, but that’s not the circumstance described in the OP. > [@](#): > > Then we can look at the best analogues of the behaviour of dinsoaurs: birds. A herd of grazing birds such as geese call almost incessantly. Hell, anyone who has ever owned free range chickens knows that they keep in constant contact with each other by calling. In my experience, a flock of _grazing_ or feeding geese don’t call all that frequently. It’s true that when flocking birds are on the move they call repeatedly (although some don’t). However, again these contact calls are different in character from those described in the OP. > [@](#): > > So to say that dinosaurs wouldn’t behave like that is inaccurate. Mothers communicating with their calves, dominance displays or simply herd bonding could all readily produce situations where the animals randomly roar. Yes, in dominance displays animals may roar or bellow. Communication calls between mother and calf, or between herd mates when the herd is not moving, are usually not that loud. Perhaps we are differing in how we are visualizing the scene described in the OP. It just seems to me that behaviors depicted in the _Walking with . . ._ series are often not very accurate in analogy with the behavior of modern animals > [@](#): > > Once again if birds are used as the piont of comparison this is pretty normal behaviour. A chicken chasing after prey will call almost incessantly. Many birds of prey call as they chase their prey. Many birds such as shrikes also call as they chase prey. Why do they do this? I hadn’t really thought about it but I guess the idea is to frighten the prey into making a mistake, although with chickens it may also assist in communal hunting. Hens may call when pursuing prey in order to alert their chicks. With regard to birds of prey, I can’t recall ever hearing one call while in pursuit (and I’ve often watched Peregrine Falcons rapidly chasing prey). Other birds I’ve seen pursuing prey also don’t often call except perhaps to alert flock members. While it may happen, in my experience this behavior is pretty rare.