Modern Crocodiles Are Evolving at a Rapid Rate

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.

radicalbyte4• 5 years ago

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

ykevinator3• 5 years ago

Thanks for this I'll check it out

dpeck• 5 years ago

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

agarsev• 5 years ago

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.

Hayarotle• 5 years ago

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.

mickjagger• 5 years ago

Off topics but it’s pretty interesting that Nile crocodiles are now in Florida.

They’re big and they eat people.

peanut_worm• 5 years ago

We have Saltwater Crocodiles too

Digit-Al• 5 years ago

Just be glad it's not the 40ft long "terror crocodile".

mrfusion• 5 years ago

I never understood why they don’t eat more birds. You’d think they could come up underneath and grab a duck or goose. And I always see birds just hanging out nearby.

ethagknight• 5 years ago

Maybe because there’s just not that much meat on them bones? If it was a nice fat juicy chicken, sure, but a river rat bird?

BurningFrog• 5 years ago

I'd guess these birds can sense an approaching croc.

fullstop• 5 years ago

Smaller birds have a symbiotic relationship with crocodiles. The crocs get teeth cleaning and the birds get to eat.

muh_gradle• 5 years ago

"crocodiles have changed dramatically in the last two million years" is a pretty important statement to keep in mind. Whenever we discuss modern animals and traits that are evolving, it's a bit misleading to not apply the time frame.

rozab2• 5 years ago

I did expect this to be about them reacting to climate change and other human factors, as there's been many stories like this recently. But I suppose a couple million years is a blink of the eye for a family this ancient.

andyxor• 5 years ago

Soon they will start a popular startup incubator and change VC investing as we know it

Modern Crocodiles Are Evolving at a Rapid Rate

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