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T-Rex problems (i.imgur.com)
submitted 2 years ago by to c/4chan@lemmy.world
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[–] 13 points 2 years ago (7 children)

Theropods were warm blooded, like birds. They would not be able to endure without eating for weeks and months at a time like modern cold blooded reptiles.

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  • [–] 14 points 2 years ago* (6 children)

    You're conflating how warm bloodedness works in mammals with how it would work in theropods. They were warm blooded because they could not shed heat from metabolic processes due to their volume to surface area ratio, not because their bodies needed it. We still do not understand how it actually worked. This is evidenced by us still not knowing the reason why stegosaurus had plates, Spinosaurus had their sail etc.

    Also, some birds can go weeks without food during migration or injury. Further to this, theropods are many magnitudes of size larger than birds. They would have far greater fat stores than modern birds.

    Disclaimer, this is based on my 16yr old zoology major, and we are in a dinosaur discovery golden age so something may have changed.

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  • [–] 7 points 2 years ago (4 children)

    We know juvenile T-Rex grew alarmingly fast, so high metabolism is in their wheelhouse. They were also rather optimized for running, so that warm blood may have been used for high-energy travel, like Tuna.

    That being said, they might be able to modify their metabolism based on food availability, but that would mean they slow down significantly when hungry. If they use torpor to subsist in such circumstances, that might leave it vulnerable.

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  • [–] 2 points 2 years ago (1 child)

    Since we only found 3 trex skeletons how could we know if their young grew fast?

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  • [–] 1 point 2 years ago

    We have over 40 T. rex specimens, and many more Tyrannosaurs. We can age them and observe growth rates by measuring bone rings, just like tree rings. Jane and Petey in particular had lots of new bone growth when they died as adolescents.

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  • [–] 2 points 2 years ago (1 child)

    Eh, big stretch we knew their young grew so fast when there is so little fossil evidence to indicate as such. I mean, there's very few complete t tex fossil finds, and even fewer that are juvenile. You'd likely have more success throwing darts at a dart board than predicting anything based on what we've found. As for being optimised for running, were still not sure how that worked. I mean, a lot of big cats are optimised for running, but very few run for sustained periods. See lions, cheetahs, tigers, etc.

    Yeah, they could enter a torpid state, but that doesn't mean they have to be vulnerable. We have many large reptiles now that do the same and aren't at a significant risk of predation, if they were they wouldn't do it. Also, we have some mammals that do the same and they aren't predated to the point that they stop doing it.

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  • [–] 2 points 2 years ago

    Not a stretch at all considering the very well studied nature of the over 40 remarkably complete specimens we have. We can tell how much an animal grew from the thickness of bone rings, very much like tree rings. Tyrannosaurus in particular had massive growth after their thirteenth year, matching humans maximum growth spurt sustanied over 5 years or so.

    Tyrannosaurus feet bones were shaped to lock together and function as a sigle unit. This reduces the energy cost of walking and is only found in a few other groups of dinosaurs, all of which are long-distance runners. A similar situation can be seen in horses and other ungulates, and to some extent humans and wolves. Cats on the other hand have very open foot structures, being optimized for sprinting and flexibility rather than running.

    As for torpor, that was an offhanded idea, thinking about it again, torpor is usually used to conserve heat, so probably not necessary for T. rex.

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  • [–] 4 points 2 years ago

    I think the interesting question is, how the the lower oxygen concentration on the atmosphere will affect the T-Rex. Is it low enough to kill it? Will it just weaken it enough that the heat produced will do some damage? I have no idea.

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