Low metabolism and they live in fresh water, shielding them from the heating impulse after the impact. Fresh water ecosystems fed by detritus from dead plants could survive the post-impact period of darkness as well.
Don't have an answer other than to say their lineage is sturdy enough to have pulled it off twice - crocodylomorpha were just about the only survivors of their giant and dominant clade in the end-Triassic extinction and, of course, they made it past the asteroid 135 million years later.
"Gee, I don't know. Maybe deep down I'm afraid of any apex predator that lived through the K-T extinction. Physically unchanged for a hundred million years, because it's the perfect killing machine. A half ton of cold-blooded fury, the bite force of 20,000 Newtons, and stomach acid so strong it can dissolve bones and hoofs."
In addition to the more detailed quoted answer, I believe the surviving mammals mostly lived underground, shielding them from many of the worst effects happening on surface world. Many were blind anyway and did well in the darkness of the clouded surface. Their predators all died off. The biggest remaining threat would have been lack of food, but as the other answer states, they had more flexible diets than dinosaurs and mammals that did not survive.
Q: Anyway, my problem with the argument is that some mammals obviously survived. Why? We had worse lungs, roughly the same amount of protection against the cold as many small dinosaurs... so what gives?
The earliest Paleocene scene is dire. There is a fossil locality in Montana dated to approximately 25,000 years after the asteroid hit, called the Z-Line Quarry. It reeks of death. Almost all the mammals that flourished in the region in the Cretaceous are gone; only seven species remain. Several other fossil sites divulge what was happening over the next 100,000 to 200,000 years. If you pool together all mammals from this time, there are 23 species. Only one of these is a metatherian; these marsupial ancestors, once so abundant in the Cretaceous, were nearly extinguished. All told, if you consider the entire Montana fossil record, along with other data from across western North America, the statistics are grim. A paltry 7 percent of mammals survived the carnage. Imagine a game of asteroid roulette: a gun, with 10 chambers, nine of which hold a bullet. Even those odds of survival are slightly better than what our ancestors faced in the brave new world of the Paleocene.
This bleak state of affairs raises a question: What allowed some mammals to endure? The answer became apparent when Wilson Mantilla looked at the victims and survivors. The survivors were smaller than most of the Cretaceous mammals, and their teeth indicate they had generalist, omnivorous diets. The victims, on the other hand, were larger, with more specialized carnivorous or herbivorous diets. They were supremely adapted to the latest Cretaceous world, but when the asteroid unleashed disaster, their adaptations became hardships. The smaller generalists, in contrast, were better able to eat whatever was on offer in the postimpact chaos, and they could have more easily hunkered down to wait out the worst of the bedlam.
As ecosystems recovered in the earliest Paleocene, many of the mammals that started to multiply were eutherians, the placental antecedents that were once bit players in the Cretaceous. Their tiny bodies, flexible diets, and perhaps faster ways of growing and reproducing allowed them to commandeer open niches and start building new food webs. Around 100,000 years postasteroid a new eutherian appeared in Montana and swiftly became common. Purgatorius, with gentle molar cusps for eating fruits and highly mobile ankles for clinging and climbing in the trees, was an early member of the primate line. It, or perhaps another closely related eutherian, was our ancestor.
In the aftermath of the extinction food webs collapsed as photosynthesis basically shut down for several years. Birds could find and eat seeds buried before the extinction, which along with their ability to fly long distances meant they could find enough calories to survive in environments that weren't producing any.
A fact I'm reminded of when I spook a stork/heron/crane when I'm walking my dog along the river near me. They make a crazy dinosaur sound, and in flight even resemble somewhat the classic illustrations of Pterosaurs.
Bonus link, the common ancestor of both birds and crocodiles:
I’m sure someone will figure out how to reverse engineer the sound recorded in various muds that were in turn fossilized. It’ll probably be something like a soil fungus that left traces of a piezo-materal that when exposed to dinosaur calls emitted energy that raised the probability of the surrounding mud to make some transition.
Once we have those calls synthesized we will find out that the so called asteroid impacts were high energy experiments on the part of the Silurians. Humans will attempt the same to a similar result: lather, rinse, repeat.
I'm really sorry to be that guy, but just FYI, the pterosaurids weren't dinosaurs or dinosauroporphs, and were on a pretty independent evolutionary lineage. It's astonishing how many times vertebrates evolved flight independently. It's a sharp reminder of how long dozens or hundreds of millions of years are.
Having said that, the "long necked stabby stabby from elsewhere" was a theme with the dinosaurs proper. Some have theorized that this was the hunting mode of the giant Spinosaurus.
You're right on the money with the dinosaurs=birds though though. Paleo guys even have started saying "non-avian dinosaurs" to reference the kpg "classic" dinosauromorpha, because the lineages are so intertwined. Archaeopteryx, to take one example, might not have been a bird, exactly? Birds might be even more intertwined than that, with separate bird lineages branching out at different times. The takeaway from the big extinctions is that you need to be less than fifty kilos and preferably able to dive or burrow very very deep. And be lucky, of course. Everything standing around within a few thousand miles of Cancun 65mya was probably screwed no matter how cool it was.
> ...of how long dozens or hundreds of millions of years are.
"Hundreds of millions" is less than 30 bits of information. That's a miniscule, infinitesimal amount compared to what we're typically used to dealing with. (If you choose a random number every year, that's less that 1 gigabyte of numbers, not enough for a 30 minutes of an HD Marvel blockbuster.)
Yeah, mostly it's impressive in a biological or evolutionary context, not in a raw number context. You multiply everything by every genetic piece of data, multiplied by the environmental variables, and so on and so forth, until you arrive at something insanely complex, to an extent that's hard to overstate. There's not much that can't happen in 12-24my. Although I don't like to call anything incomputable, taken as a whole, it's pretty close to incomputable. Believing otherwise is often a trap.
To take one example, older paleo people would see fossils of creatures like nimravids, and they'd say to themselves, "oh, a long-lost ancestor of the sabretooth cats!" - but they're not getting how long ten million years is for living systems. Sabre teeth didn't evolve once, or twice, or even three times, but evolved separately at least six completely separate instances, across 200-300 million years. This is true for all sorts of morphology that might look incredibly distinctive to our human eyes, but which aren't actually distinctive in fact.
Some mad scientist a while back wanted to devolve Chickens into (basically) velociraptors. This was decades back, but I could see what he's talking about. Apparently with CRISPR now some scientists are doing similar things at small scales.
We're trying to infer a query here: SELECT species FROM animals WHERE habitat IN [protected_from_burning_sky] AND diet IN [non_photosynthesis_dependant_foods]
The urge to a social-media-pedantry-dunk aside, did the title confuse you? Do you think your title or TFA's title gets the point of the article across clearly to a wider audience?
didnt you get the memo??? birds aren't real! and the last surviving dinosaurs who originally ventured into the hollow earth before the disasterous meteor strike, evolved over millions of years and became today's shape shifting lizard people that rule the world with reckless disregard for our mammalian well being
https://archive.ph/c0hHJ