Did Dinosaurs Really ROAR?

LORD OF THE SPINOSAURS - Oh, now this is a very compelling notion you've raised! Did dinosaurs actually roar? Hmm, I've a feeling theropods may have produced extremely loud braying and perhaps even keening (somewhat like an eagle straight out of hell). Whether or not these amazing animals possessed a syrinx is, unfortunately, not known for certain; though the prospect is quite compelling! With that being said, allow me to posit another notion to build upon this very intriguing thought you've presented. What if larger dinosaurs utilized infrasound - low-frequency soundwaves that could travel great distances and would be almost impossible for animals with a human auditory reception range to hear? Perhaps large theropods communicated via such low-frequency at a distance, ensuring they were well aware of one-another's territorial boundaries? Such communication is present in many of Earth's animals in this day and age - including cetaceans and elephants. Regardless, I can tell you this much: were I to hear a large theropod producing a blaring, slightly high-pitched shriek in the night, I'd bloody move to find a hiding place! This girl can deal with a lot of things, but nightmarish vocalizations from super-predators larger than most busses is not one of them! ;)

    This was an incredibly fun topic to ponder! Thank you ever so much for taking the time to compose and present this to us! :)

Wow, you certainly have made a pretty damn good discussion! I don't recall anyone ever making a disucssion like this!!!

Well, I believe some dinosaurs such as theropods could have not roared, but just make some sort of threatening sound towards other dinosaurs. Or maybe a call to warn other dinosaurs to back off territory. I personally think dinosaurs hardly made loud noises, most other animals today only make loud noises such as roars, growls, calls, etc. to "talk" with other animals, in a sense.

For the most part, I must concur with Something Real.

That being said, it seems liek you have interesting ideas for discussions, I certainly will look forward to any future debates from you!

This a pretty good first discussion. 

That said, anything is possible. Maybe theropods did roar, maybe they didn't. Hisses and grunts are likely, as are chirps. 

I agree with what's been stated above. 

I never thought of this! I'm not sure, but I think they were able to roar, but didn't do it too often. 

I actually have been debating about this for a long time, but I only got my first whiff of the argument from an article I read online (and unfortunately, I didn't save the link, oops).  I really don't know whether theropods could have roared, and the evidence for doubting it are here, but maybe their calls were deep enough that if we heard them anyway, we'd say they were roaring.

But I'm completely certain that large dinosaurs (not just theropods) used infrasound, because of their sheer size.

As well, I'm willing to bet that large herbivorous dinosaurs were capable of loud bellows and roars.  Bakker wrote in a book I read when I was younger that if a Triceratops blew its nose or tried to produce any such sound, the volume and audial frequency would have been off the charts because of their large nasal and oral cavities.

If there's one thing you should know Lord of the Spinosaurs is that Something Real makes a lot of good claims. One of the best debators of the forums.

RAPTOR-401 - Aww! How sweet! I'm humbled and honored by your statement! I'll try my best to never let you down! :)

I know this isn't an end all answer, but lets look at current animals that are similar:

Birds- Birds do not roar or growl, but they do make caws, screeches, ans chirps.  Most of these sounds however are meant to communicate with other birds and are hardly aggressive.  Perhaps a larger animal would make a deeper sound more like a roar, but that doesn't hold true with emus and ostriches.

Reptiles-  Generally, reptiles are very silent creatures aside from an occasional hiss.  If the dinosaurs are truly relatives of reptiles, I would doubt them roaring.

Crocodiles/alligators-  Once again, we are looking at an animal that mostly does a hiss.  However, these two creatures do have a low grumble that is similar to a gowl but it pales in comparison to an outright roar such as the JP T-Rex.

I would conclude that it is most likely in-between these animals.  I would guess that most of the time, the sounds made by these animals would be hisses with the occasional grunt to communicate with their own kind.  Of course, this is just an educated guess and theropod dinosaurs very well may be completely different than any animal we know of today.