Modern Crocodiles Are Evolving at a Rapid Rate

September 3, 2024 1:07 AM

Modern Crocodiles Are Evolving at a Rapid Rate. Despite their reputation as living fossils, crocodiles have changed dramatically in the last two million years. (Smithsonian magazine.)
posted by chariot pulled by cassowaries (24 comments total)

I was mentally preparing to be alarmed until I made it to the word “million”.
posted by mhoye at 1:14 AM on September 3 [8 favorites]

🐊
posted by HearHere at 1:22 AM on September 3

I welcome our new crocodilian overlords.
posted by Billiken at 4:59 AM on September 3 [2 favorites]

This post reminded me, September is here and now that it's PSL season I need to log back into Planet Zoo and give all my crocs their blood pumpkins.
posted by phunniemee at 5:05 AM on September 3

I have it one good authority that we’re probably safe until they start tick-tocking or perhaps, Tik-Toking.
posted by thivaia at 5:56 AM on September 3 [8 favorites]

They're probably rushing to evolve into crabs.
posted by Foosnark at 6:24 AM on September 3 [10 favorites]

we’re probably safe until they start tick-tocking or perhaps, Tik-Toking.

Crocodile influencers tout health benefits of long naps on riverbanks.
posted by GenjiandProust at 6:46 AM on September 3 [4 favorites]

stupid evolution, we coulda still had these guys if not for you
posted by mittens at 6:49 AM on September 3 [1 favorite]

They're probably rushing to evolve into crabs.

In this economy who isn’t?
posted by mhoye at 7:31 AM on September 3 [5 favorites]

Bring back the bipedal crocodilians, I say.
posted by [insert clever name here] at 8:10 AM on September 3 [1 favorite]

Over and over again, Felice and colleagues found, modern crocodiles are converging on a small set of skull shapes. Africa’s Nile crocodile and Morelet’s crocodile of Central America are not especially close relatives, for example, but they’ve evolved remarkably similar skull shapes. Likewise, today’s broad-snouted caiman of South America has a very similar skull to the extinct crocodile Voay whose remains are found in Madagascar. This is why they seem ancient. It’s not that they’ve gone unchanged, but that crocodiles are evolving into a limited number of forms over vast spans of time. Look at a saltwater crocodile and you’re seeing the revival of one of evolution’s greatest hits.

You kids might think you're all cool and retro but really you're just derivative.
posted by flabdablet at 8:18 AM on September 3 [1 favorite]

It's all because they traveled at Warp 10.
posted by JHarris at 8:29 AM on September 3 [3 favorites]

Crocodile influencers tout health benefits of long naps on riverbanks.

I'm not trying to tell you what to do, crocodile influencers, but if you're looking for sponsors, dental care is going to be a gold mine for you.
posted by thivaia at 8:54 AM on September 3 [2 favorites]

Fascinating!
posted by ellieBOA at 9:39 AM on September 3

Probably due to evolutionary pressure to adapt to shovel-bonking
posted by qxntpqbbbqxl at 10:39 AM on September 3 [3 favorites]

Despite their reputation as living fossils, crocodiles have changed dramatically in the last two million years.

Same here, crocs, same here. I feel you.
posted by Naberius at 11:32 AM on September 3

I welcome our new crocodilian overlords.

This sounds scary, but I may warm up to the idea if it gives me a reason to say "crocodilocracy" a lot.
posted by Avelwood at 12:12 PM on September 3 [3 favorites]

Today I learned you can spell “crocodilians” with a “y”. Y? I don’t know.

But any discussion of crocodilian evolution is incomplete without mention of their remarkable circulatory system, which puts ours to shame.
posted by TedW at 1:11 PM on September 3

And by way of further explanation, their circulatory system is arranged so that blood does not flow to their lungs when they are underwater, saving the heart from unnecessary oxygen consumption and allowing them to stay underwater much longer than would otherwise be possible.
posted by TedW at 1:32 PM on September 3 [1 favorite]

i love crocodiles
posted by Kutsuwamushi at 1:34 PM on September 3 [1 favorite]

honestly more things should be crocodiles
posted by Kutsuwamushi at 1:34 PM on September 3 [3 favorites]

I looked at the caption on the figure at the beginning of TFA:

> A gharial has the same skull shape as some extinct crocodiles. This skull shape has likely evolved three different times during the history of crocodiles

and came straight here to make some observations. Well not quite. I scanned the thread along the way, and saw

> They're probably rushing to evolve into crabs.

Which is more drastic than what I had in mind. Which is namely the repeated appearance of the "sabre-toothed predator," which is where you get when you realize that all the "sabre-toothed tigers" were not even proper cats, and then that some of them were not even proper felids, and finally that some weren't even placental mammals, maybe even non-mammalian therapsids.

So, same head re-evolved 3 times? Phfffth. The sabre-tooth adaptations happened 4 times just within the lineage of felid mammals. Once more in another now-extinct catlike placental mammalian clade, and at least twice among non-placental (maybe even non-mammalian) mammal ancestors.

Evolution, like history, does not repeat itself, but again like history, sometimes it sure does rhyme.
posted by Aardvark Cheeselog at 1:37 PM on September 3

Good job evolution. Crocodiles need middle legs, so they don't have the look of toothy weeny dogs. middle legs is probably better for their backs too. I bet a crocodile would request back rubs if it could speak English and not just roars.
posted by The_Vegetables at 2:17 PM on September 3 [1 favorite]

Potential sponsor list for crocodile influencer updated to include: robot legs, back massagers
posted by thivaia at 6:45 PM on September 3