Tyrannosaurus Rex is now thought to have possibly had lips. Less of chance of it roar though I was told by a friend just because there are birds doesn’t mean they can’t.

Evolution isn't linear, just because one branch of a tree could/couldn't do something, doesn't mean 70+ million years later descendants could/couldn't do it too?

  • $\begingroup$ there's info on that here. washingtonpost.com/news/morning-mix/wp/2016/07/12/… The thoracic musculature uses bones that describe some kind of roar power if it is present. $\endgroup$ – com.prehensible Jan 22 '18 at 12:51
  • $\begingroup$ birds and crocs can't that's called bracketing, which is not definitive but a good indicator. $\endgroup$ – John Jan 23 '18 at 5:54

Careful now: T Rex was not a bird, it was a non-avian theropod. Birds are dinosaurs but not all dinosaurs are birds. In the same way, tigers are cats but not all cats are tigers.

The argument that T Rex could not roar is not only based on none of its closest relatives being able to as you seem to indicate. Dinosaurs (and by extension birds) are archosaurs, a clade that includes crocodilians too and crocodilians are quite a bit more close to the basal form of archosaurs than T Rex was. Crocodilians can only sort of "hiss", not roar in the colloquial sense. And birds cannot roar. This is a decent start to a thought process but this isn't really the argument for why dinosaurs likely didn't roar in the past.

Researchers who have studied the potential vocalizations of prehistoric, non-avian dinosaurs have found indications that similar closed-mouth vocalization to those found in other living archosaurs are very probable: https://news.utexas.edu/2016/07/11/dinosaurs-may-have-cooed-like-doves

Closed-mouth vocalization is not really compatible with what people typically think of as roaring. It still allows a variety of sounds that don't necessarily (though perhaps probably) somewhat resembled crocodialian or simple bird vocalizations. So no, it's not impossible that some non-avian dinosaurs could roar but the current state of our knowledge is that they very likely could not.

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  • $\begingroup$ so you are saying they couldn't roar at all since u say they could not in the end :( $\endgroup$ – Gian Jan 21 '18 at 3:57
  • $\begingroup$ I'm not claiming that they definitely could not. I'm saying that the current scientific consensus seems to be that they probably could not. $\endgroup$ – MM8 Jan 21 '18 at 4:01
  • $\begingroup$ I guess they couldn't :( $\endgroup$ – Gian Jan 21 '18 at 4:10
  • $\begingroup$ Of course you have to ask yourself, if you scale a goose honk up to t-rex size, how different is it really from a roar. $\endgroup$ – John Jan 21 '18 at 17:30
  • $\begingroup$ a cooing T-rex :-) $\endgroup$ – Fizz Jan 22 '18 at 18:53

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