I recall reading this wacky theory years ago. The gist of it was, that herbivorous dinosaurs had a problem digesting seed-bearing plants. As time went on, harder seeded plants began to displace the older spore-propagated plants that the dinosaurs ate. this caused problems for them, including constipation and malnutrition.
Of course, the meat-eaters died off faster, since they were dependent upon the herbivores.
Anyone else ever read anything like this?
I can say with great authority that I’ve never heard of such a theory.
Never heard of that, but I’m still looking for confirmation for something I once heard about the sailback dinosaur.
This is the one with the big sail-like ridge on its back. The ridge was to help regulate temperature: if you stood with the sun on it, it would warm you; if you stood parallel to the sun, it would radiate heat. Someone once told me that the dinosaur died out because the climate changed and it got windier, which blew the dinosaur over making it vulnerable to predators.
It sounds fishy to me, but who knows?
So the dinosaur would be smart enough to figure out how to stand parallel or perpendicular to the direction of the sun’s rays, but not smart enough to figure out the same with the wind?
I’d go with your “fishy” instinct.
Why am I envisioning this?
A T Rex at a karioke bar singing “Come sail away, come sail away, come sail awaayy meeee…”
No one, I suspect.
What would one find in the fossil record to indicate such a thing?
As to the first claim, does the fossil record show an increase in the number of seeded plants in the late Cretacious period? (I don’t know. Maybe it does.)
So dinosaurs became dinosaurs because of constipation? No shit!
It was a real idea. It was postulated by E Baldwin in 1964 in his book An Introduction to Comparative Biochemistry.
He was given support in 1983, though when R H Dott Jr published “Itching eyes and dinosaur demise” Geology 11:126, which linked the rise in pollen production from Angiosperms to terminal hay fever among the dinosauria.
NB some scientists occasionally stray from the serious 
Not being able to poop for 10 million years would make my eyes water, too.
What the OP is describing is what James Morrow says in his novel “Blameless in Abaddon”. It is the second novel in his Godhead trilogy. A fun read.
The main character, Martin, decides to put God on trial after God has “died” and his body fell into the ocean. To gather evidence for his case he and his gang enter God’s brain. Inside they find the “idealized” version of things. Along their journey they run across some talking dinosaurs drinking tea or something and they tell Martin that thye want to be apart of the case of evidence against God because he killed them off and they thought it was unfair.
The dinosaurs say that they went extinct because of constipation. That God changed the plants so they were hard for the herbivores to digest and they got constipated and then the herbivores started dying off and then the carnivores started dying off because there were no more herbivores.
Before the Alvarez team gave us the first real evidence for an impact hypothesis, scientists were all over the map on postulating causes for the extinction. Knowing what I now know, I think it’s weird that so many theories focused on some perceived weakness of the dinosaurs as the cause for extinction (big slow lizards’ eggs eaten by tiny mammals; brains too small in proportion to body; and so on) when the evidence shows so many other types of life experienced mass extinction at the same time.
And this is the key point. It wasn’t just dinosaurs that went extinct. All sorts of organisms went extinct, of all types, on both land and sea. Any extinction theory has to account for the simultaneous extinction of dinosaurs, marine reptiles, pterosaurs, toothed birds, ammonites, and many others.
Many dinosaurs did of course swallow rocks, usually small river cobbles, that wouldn’t pass through their system but instead stay in the stomach to grind together and against food, thus aiding with digestion. They’re called gastroliths, are smooth but pitted from the acid, and I’ve come across small piles of them while hiking across the Jurassic Morrison Formation in Utah’s San Rafael Swell, obviously the final resting place for that fallen dino.
I’d be curious how the timespan of gastrolith usage coincides with the advent (and hardening?) of seeded plants.
I have heard of this theory before, and it’s not crazy - nor is it from a novel. Gymnosperms (flowering plants) very quickly took over the planet near the end of the Cretacious period. On a geological time scale it’s impressive. Paleobotany is almost all ferns and conifers and then BOOM! flowers. Knowing what we do about the way the gymnosperms war with each other through chemical toxins, and how they use toxins to discourage things that would eat them (where do you think our insecticides come from?) it’s not insane to tie the rapid rise of gymnosperms, and their toxins, to a die off in the animal population of the time.
Imagine you’re a sauropod. Your ancestors have always fed on plains of ferns. But nightshade berry plants take those fields over in just a couple of generations. You can’t evolve quick enough.
Butterflies manage the sunshine warming, and they’re not smart at all. There’s an abstract of a paper
here, and a description here (scroll down to “Thermo-regulation”). I doubt if they understand wind.
You transposed Gymnosperms (conifers) with Angiosperms (flowering plants). It’s the Angiosperms that exploded in the Cretaceous. But Angiosperms evolved during the Cretaceous, not the end. There was a lot of rapid change in dinosaur lineages between the Jurassic and the Cretaceous, and that might have beend due to the evolution of Angiosperms, the Sauropods dominated the Jurassic but Ornithopods dominated the Cretaceous.
Yep. I was posting it all from memory, so it doesn’t surprise me that I screwed some things up.