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Comment by littlestymaar | Hacker News Reader

Last summer at a wedding, I met a paleontologist studying ancient crocodiles and his story was fascinating:

Before the K-Pg extinction, Crocodilia was a pretty wide order, with many different species occupying multiple ecological niches, from herbivore crocodiles with teeth like cows', to cat-sized running crocodiles living in the desert. And during the K-Pg extinction, most of it disappeared with only a handful species remaining, occupying two really close ecological niches (semi-aquatic opportunist predators and semi-aquatic fish eater (gharial and galse gharial)).

And he contrasted this collapse with what happened to dinosaurs (also know as birds), which today still have thousands of species occupying almost every possible ecological niche.

View on HN

What happened at the K-Pg limit with dinosaurs and crocodiles is similar, both went from being very wide to a handful of species remaining. The difference is what happened afterwards, when the few (single?) species of dinosaurs that remained diversified into what we now call birds.

The interesting thing from the article is that crocodiles are still evolving rapidly, but not diversifying! they seem to be successful in their narrow and specialist niche.

I wonder how close crocodilians were to being extinct after the K-Pg limit. If they did, they would be another non-dinosaur archosaurian group only known from fossils, like pterosaurs. Someone from such timeline would probably be delighted to see alive, as seeing one would be the as amazing for them as seeing a pterosaur or triceratops would be for us.

They're the last living non-avian archosaurs. We sure take crocodilians for granted.

That sort of aquatic ambush predator niche has always been very successful, so I think we'd end up with a similar animal with a similar body plan that would fill the niche; it's evolved many times before.

https://bmcecolevol.biomedcentral.com/articles/10.1186/1471-...

I can strongly recommend the recent In Our Time podcast (subscribe, it's a hidden gem!!) episode over this very subject:

https://www.bbc.co.uk/programmes/m000zmhf

Thanks for this I'll check it out

I was about to recommend the same thing. This was a great episode in an already great series!

It's basically Joe Rogan for smart and sane people. None of the grifters, all of the scientists + academics. Been going on forever, covering a huge range of subjects.

Joe Rogan? Was interested, now no longer. Using Joe Rogan to describe a podcast cheapens your pitch. Unless your saying the podcast is trying to have incredibly broad appeal without much consideration to intelligent thought or the impacts of what they are putting out to the world except in order to increase their own viewership numbers.

It's a wonderful podcast. It's nothing like Joe Rogan. Here's the episode list:

https://www.bbc.co.uk/programmes/b006qykl/episodes/player

And note that when you click to an episode to see who the guests are (usually three professors or other experts on the given topic) there's also a reading list.

I guess it's similar to Joe Rogan's show in that it's a recording of people speaking.

Yah just listened to the first one on the Manhattan project. Its really great, nothing like Joe Rogan. Thanks OP for the great find.

It does have a Uk lean to it, but very understandable and not too heavy at least in the first one.

Joe Rogan occasionally has some super interesting podcasts where he invites an academic/expert or two out to talk about their specialisation. He listens, occasionally asking a question.

That's how I first encountered him - he was interviewing John Carmack. The later episodes were disappointing, but I spent a year keeping an eye on the guest list. There were maybe 4-5 really good interviews in that year.

In Our Time is like those good episodes but with an extremely high signal-to-noise ratio and generally better.

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