My understanding is that there is mounting evidence that dinosaurs were actually warm-blooded.
Cold-Blooded Dinosaur Theory Put on Ice
Not saying the evidence is definitive, but still thought it odd to see this stated in today’s column so matter-of-factually.
I thought the jury was still out on the warm/cold blooded question. Nevertheless, is this the column to which you are referring?
We sometimes confuse dinosaur species as living all together. However, there aren’t be any “A tyrannosaurus and a stegosaurus walked into a bar” jokes because these two creatures didn’t live at the same time. Plus, tyrannosauruses aren’t welcomed in too many bars. They tend to eat the other patrons.
However, dinosaurs as a clade weren’t doing so well a million or so years before the KT event. That event certainly didn’t help, but the rate of dinosaur evolution was slowing down. Meanwhile, mammalian evolution was starting to pick up and larger and larger mammals started to appear. Still, by the KT boundary, there was no doubt that dinosaurs were still the dominant clade.
Dinosaur difficulty may be related to the spread of angiosperms – the flowering plants that dominate our current landscape. These started out in the early Cretaceous, but by 100 million years ago (mid Cretaceous) had started to spread globally. By the time of the late Cretaceous (65 million years ago), angiosperms had replaced the conifers as the dominant large plant group.
It could be that the spread of angiosperms interrupted the environment for the dinosaurs. Or, it could be that mammals – who started out as insectivores – were able to start eating the highly nutritious angiosperm seeds. Something happened where even the smallest dinosaurs which were the size of mammals became extinct while the mammals lived on.
Interestingly, the ancestors of the mammals, the synapsids, were the dominant life form until replaced by the sauropsids, the dinosaur ancestor at the start of the Triassic – at the time of an even larger extinction event than the KT.
My understanding is that the evidence for warm blooded is mounting and is believed by a significant majority, but is not accepted as a concensus opinion.
You’re an idiot. The reason T-rexes aren’t allowed into bars is because they can’t reach the pints with their itty, bitty arms.
No, it’s because they tended to eat the entire bar and spit out the bones. No class.
They can reach the pint, they just can get it up to their mouths…
What’s with this “K-Pg event”? I’ve always heard of it as the “K-T” event.
The small dinosaurs didn’t die out. That’s why we have birds.
According to Wikipedia, the Tertiary Period is no longer in favor as a division of geological time, at least not by the relevant authorities. You now have the Paleogene and Neogene Periods occupying its space (plus the Quarternary Period’s start date was moved earlier into what was once the end of the Tertiary).
Powers &8^]
As someone who suffers from severe hay fever in Spring and Fall, I can easily see this as a possibility, especially given the lack of antihistamines back then.
Re: The illustration accompanying the article. I don’t speak Spanish, but doesn’t ‘Culo agua’ mean ‘ass water’? (I used to work with a guy who’d snicker about another coworker whose surname was Culotta.)
I recall reading in Carl Sagan’s Cosmos that whatever killed the dinosaurs killed off everything of more than 50 pounds mass. Am I remembering correctly?
If mammals worked so well…why are there still eggs?
How come chickens don’t have pouches of little chicks about?
Reptiles had the same amount of time to evolve and adapt, why didn’t the warm blooded mammalian life style take to them?
What the hell is fishes?
Because they adapted in a different direction. The reptiles have advantages; the simpler reptile form tends to flourish in places where the resource-hungry mammal form doesn’t do as well; islands, deserts and the like.
Evolution has no direction and isn’t a ladder, with everything moving towards some “superior” form (which just happens to be us, naturally)
Didn’t kill off the crocodilians.
The line in the article that really sparked my curiosity was this:
“Fifth-worst”? :eek::eek::eek: I want to know more about the four bigger ones!
Hi JoelWhy!
My understanding is that the clean ‘warm blooded’ concept is illusory. Animals of all types have many mechanisms for maintaining temperature (and true cold-blooded animals do not but rely on environment).
Cretaceous megafauna of the dinosaur bent kept warm and active a whole lot by being plain old big. They didn’t need much insulation and a metabolism that burned even when the creature was sluggish simply to keep the furnace going. The bigger you are, the less surface area you have per unit of volume; therefore, the less heat loss.
If anything, dinosaurs may have had a problem with overheating.
So that solves the problem with being active even when it’s a might chilly out. *Until *the climate changes significantly. It’s like they were warm-blooded in a way that only worked in one climate. If temperatures change significantly, they don’t fare so well.
Which dinosaurs survived? The smaller, well-insulated (with feathers) ones. They kept warm by a different method, and they can cool off when they need to by arranging their feathers differently.
I found it. Wikipedia is our friend: http://en.wikipedia.org/wiki/Extinction_event#Major_extinction_events
Don’t worry. *Your *ancestors made it.
And it turns out I’m talking out of my ass!
It is true that big dinosaurs would have little problem keeping warm, but I posted this idea to some professional paleontologists and the first reply I got was:
So I think you’re right - **Cecil **has some ‘splainin’ to do.