is the fact that dinos didn't survive the KT extinction but many reptiles did evidence dinos were homeotherms?

[andrewsaurus rex]

it seems to me that the ability to go very long periods of time without food and in many cases water would have been an enormous advantage at the time.  Perhaps an advantage dinosaurs, marine reptiles, pterosaurs etc did not have, resulting in their extinction, whereas many types of reptiles survived?  So is this 'proof' that dinosaurs et al were warm blooded?

[Halichoeres]

It could at best be considered circumstantial evidence. The depletion of plant life was severe enough that even large-bodied poikilotherms would have starved.

[andrewsaurus rex]

yeah, I recognized it could never be considered as proof.....I was hoping for better than circumstantial though. 

It's always seemed puzzling to me that zero dinosaurs survived the extinction, while a significant variety of reptiles and even birds did.   There must have been something unique to dinosaurs/pterosaurs/marine reptiles that made them particularly vulnerable, other than their large size....there were afterall, many species of small dinosaurs/pterosaurs and even marine reptiles around at the time of the extinction.  Why did zero of them survive, while some other similar animals,  of similar size, did?

One big flaw  with my 'it's because they were all warm blooded' theory, is that birds survived the extinction and they would have almost certainly been warm blooded.  So some warm blooded animals survived....just not any dinosaurs, whether they were warm, cold or somewhere in between. blooded.

[ceratopsian]

Not all bird lineages survived. Enantiornithines didn't make it through.

[Gwangi]

You keep saying that zero dinosaurs survived, but the birds are dinosaurs, and they survived. With birds it was likely a combination of flight ability, small size, and diet that helped them scrape by. Diet is probably key because many birds eat seeds, which would have been one of the few remaining food sources after plant life died out. Small invertebrates would have been around too. Small mammals survived and also would be eating seeds and small invertebrates. But that's not a food source that larger dinosaurs could live on. And ceratopsian is correct, not all birds survived, entire lineages died off. Not all mammals survived either. I saw somewhere that 95% of mammalian life also perished. I don't remember where that figure came from so take it with a grain of salt, I think it was from a documentary. The point is that even though some groups survived, it was just barely. It's not like they were thriving while everything else was dying.

[andrewsaurus rex]

all good points, especially the surviving on a diet of seeds point. 

I didn't mean to imply that everyone else did just fine while the dinosaurs died out.  I am aware that other types of animals barely made it.  But it still seems curious that no dinosaurs (excluding birds), no pterosaurs and no marine reptile lines survived.  None.  While at the same time, a smattering of most other types of animals did.  You would think some dino/ptero/marine reps would have made it too, just like some mammals, some birds, some amphibian/reptiles etc did,