How Crocodiles Survived The Ice Age

Look, I don't mean to burst your bubble or cause any alarm, but you should know, we are still living in an ice age.

Yep, we never left it. I know I know, sometimes when it's summer in your ACs and working, it may not feel like we are, but we are.

And you can tell this by the giant blocks of ice that exist year round in the north and south poles.

As in a general sense, as long as there's permanent glaciers and ice sheets in the planet, many consider that good enough evidence for that an ice age is occurring.

In this particular one began about 34 million years ago during the Eocene Legacy in Boundary.

After in dark it can move south enough, got a new cold current, and froze, leading to a domino effect, and the rest is history.

So, in other words, it's been happening for a while.

Of course, though, like anything, the intensity of this event is fluctuated from the start, with some parts of the ice age being pretty tame, while others got pretty sketchy.

And this included a few smaller events within, such as the last glacial maximum, a period where the ice sheets reach their maximum extent.

And this sub-event, if you will, happened at much more recently in time than you might believe.

A bit over 30,000 years ago, give or take, with global temperatures dropping over 6 degrees Celsius or 11 degrees Fahrenheit, and thus leading to an expansion in the ice.

And even during the summer, it's believed that 25% of the earth's land could have been covered with ice, with ice sheets expanding over much in North America, Europe, and even small parts of Asia and South America.

And these ice sheets were absolute monsters, at least in size, being up to 4 kilometers or 2.5 miles thick, which is for reference, nearly 5 times the height is the world's tallest building, and thus resulting global sea levels dropping by quite a bit, and making the world look like this on a map.

Now, again, this is just one extent of extreme cold, which as far as we know seems to have been the most severe spell, representing the coldest point the earth has been for possibly a few hundred million years, maybe even more.

Yet, with that said, it does seem that there is multiple similar cold spells sprinkled throughout.

And so, unsurprisingly, this extreme climate, mixed in with the physical ice sheets, impact on sea levels, and the change in environments, lets a many animals perishing directly or indirectly do the ice age.

In one group that suffered many losses, and underwent a significant paradigm shift, if you will, was our cold blooded pals, the reptiles.

Now, prior to the ice age, reptiles have been doing surprisingly well, contrary to what the Sennhezoic's nickname, The Age of Mammals, may have you believe.

And actually, in various continents and bodies of water, reptilian groups that hop dogs around, not mammals.

Not to mention that many were seriously giant, such as the sea serpents, terrestrial snakes, landcrops, sepikids, and luscus on.

And their size was probably things of the warmer temperatures seen in the early Sennhezoic, especially during events such as the Eocene Thermal Maximum, which was a bit like an extended summer.

In all this heat, it had wrapped thousands during bigger, as with their cold blood in nature, it's much harder for reptiles to generate their own body heat compared to mammals.

And thus, they rely on external factors, so when things are warmer, they have to worry less about their requirements, and also allows them to perform other functions better and preserve more energy.

In contrast, when things get really cold, they tend to suffer, and studies have found the ice age heavily impacted the overall size of reptiles, as well as their extinction rates.

With studies on certain islands throughout the ice age, for example, finding that numerous reptiles simply cannot withstand the changes.

And then when you add in the fact that a colder environment typically means less productive environment as well, meaning less prey, it's no surprise that the bigger reptiles struggle the most.

And so, with all this said, the reptiles of today are typically much smaller than those of old.

However, if you take a look at every group, you'll find one that is strangely resisted bending to the cold, so to speak.

And are a pretty unlikely survivor of the ice age, as they're known to love heat, and are still absolutely massive, occupying 8 to the top 10 spots for the largest reptiles on Earth from a white standpoint.

And the largest of them is literally 10 times bigger than the largest snake.

And of course, I'm talking about crocodiles, or rather crocodilians.

Yeah, these carnivorous reptilians are among what I think to be the strangest survivors of the ice age.

I mean, we lost things like saber-toothed cats, various elephantids, etc., etc.

But crocodiles? Nah, they made it out.

And this does lead to a rather interesting question of how did crocodilians evolve things actually survive the ice age?

And as it so turns out, it wasn't just one thing that saved them, but a few, with the only true single statement being that they are simply built different.

They are truly wonders of evolution, and you have to remember that modern crocodilians, i.e. members of the Order of Crocodileia, had already survived some pretty messed up stuff prior, such as the KT extinction event, which, as you may know,

killed all the non-avian dinosaurs, nipped the crocs, somehow brushed it off, and were among Earth's largest survivors, despite the fact that the planet got a bit chilly afterwards back then as well.

You know, with all that ash and dust blocking out the sun.

So basically, these guys have survived asteroids, mass extinction, ice ages, you name it.

And yet they're still here. And their survival through that event, and the ice age, are in some ways a bit linked, as crocs use some of the same traits to creep by both events, including one that simply had to do with their lifestyle.

As you may know, crocs are very fond of water, having evolved to be semi-aquatic, and many can stay submerged for long durations of time, with each having evolved unique ways to maximize their breath, including drastically slowing down their metabolism, and in some cases even utilizing a specialized heart-shunt that helps redirect oxygen from the lungs to vital organs.

And all this doesn't include the simple fact that they can also just chill in the surface of the water if they want.

And this is all to say that crocodilians do just fine water, and don't often need to leave, which help them a lot during the ice age.

As contrary to what a hot or cold bath may have you believe, water is actually very hard to heat or cool, relatively, essentially requiring more energy to change the aquatic environment than a terrestrial one.

And thus spending large amounts of their life in the Agua helps crocodilians.

As the longer time it took for the temperature of the change in the water, the better it allowed populations to deal with climate shifts, whereas on land, the shifts in climate could have been more severe, sudden, and drastic.

Additionally, throughout the ice age, certain watering environments did seem to be more stable than other environments, when it came to the food chain, with collapses being less common, which helped keep crocodilians nice and plump.

And that was, and still, is another key advantage for crocodilians.

As simply put, crocs are not picky eaters.

I mean, I guess you could argue that some kinds, such as the garials, want sushi only, but generally speaking, this group eat about just whatever they can.

I mean, there is a reason why crocodiles are one of the few animals considered to be natural predators of humans.

If it moves, it's game.

And the same largely goes for members of the alligator a day too.

I mean, just take a look at the American alligator, who's known to eat everything from insects, all the way up to cattle with the opportunity to percents itself.

And because this generalistic lifestyle, crocodilians weren't as heavily impacted as others, when a few animals vanished here or there.

Or when a new species popped up every once in a while.

And it certainly helps that these guys possess some ridiculously overpowered offensive and defensive capabilities that allow them to compete with pretty much most animals evolution throws to them.

For starters, many crocodilians have evolved giant or bust monstrous skulls, capable of dishing out ridiculously high bite forces.

With the salt water crocodile, actually holding the title for the strongest bite force on the planet, currently, at least from verified tests.

With one study measuring a bite to over 16,000 newtons in force, which is easily more than enough power to shatter your femur, the strongest bone in your body.

Then on top of having ridiculous bites that can crush bone, the vast majority are also capable of performing the infamous death roll, including some garials even.

We're in a crocodile bite down on its prey, hold on to it like your mom might have pinched your ear, and it will start to spin continuously, using their powerful tail for rotation, which allows them to tear massive chunks of flesh off, or many times even lips.

So, as you can see, and as you probably knew, they've got quite the ability to kill, and then on the flip side, they themselves are not the easiest to kill.

Seeing that this group has homemade built in armor, which comes in the form of seriously tough skin, scales, and boning scoots known as osteoderms, delay underneath repudermal scales, and provide these creatures with an immense level of durability.

And I think one real world example this shows is pretty well, is a recent story about an Australian.

It's always them, isn't it? And one day, said Australian, was nicked by a crock while walking near the water.

Lucky for him though, he had a knife, which he used to stab a crock at our repeatedly in the head.

While the crock did let go, it was perfectly fine, minus a few superficial scrapes in the blade, which mind you was on the larger size, not a butter knife.

In this level of defense and offense, has made these guys 9 touchable, and ridiculously hard to get rid of.

A benefit to have wherever, whenever, and especially during a time of heightened hardship, in final turnover is high.

But with this said, one of the biggest reasons why crocketylings made it out of the ice age, actually has nothing to do with their physical features, rather just simple geography.

As for the most part, they simply stayed away from where the ice was.

To be a bit more specific, while movies and documentaries may have you believed the Earth was a giant snow globe during the last glacial maximum, it wasn't.

Some areas didn't even have ice or snow, with warm and tropical areas still existing, albeit these regions were a bit more limited and presently, with these two maps showing the difference between now and the last glacial maximum.

And as you can see, while yes, there was much more ice prior, hot spots definitely remained.

And if you take a look at where crocketylings are found today, you can see that their global range aligns pretty well with where the ice was absent, thousands of years ago.

However, this isn't to say that all of them got off scot free.

Seeing that during warmer interval periods, some species, such as the American alligator, were known to live closer to the poles than they do now.

And when things started to get a bit too cold, they did see reduction in their range, in a drop in overall population.

But with this said, don't let this take away from the impressiveness of the situation.

As again, all places did see drops in temperature, tropics included.

And multiple kinds of crocketylions did in fact experience and survive, at least temporary freezing conditions, conditions that would likely kill most other large drop tiles.

Yet crocks are some pretty nifty tricks of their sleeves, or scales, that they bring out when things get a little chilly.

And one of the coolest examples of this, no pun intended, is seen again in the American alligator, which has developed a pretty nifty ability known as Pirmation.

Think of this as being like, hibernation, in a way, but still different.

And essentially what it is, is that when things get too cold for alligators, and for other animals that permeate, they will go into a state of dormancy, where their metabolic rate will drastically slow down, and they will become extremely little targic.

And in this state, they won't fall into a complete slumber, but they will stop doing certain activities, such as eating.

Whilst in the flip side, they will keep up drinking in order to stay hydrated.

And so obviously, this slow down allows them to conserve energy, and store resources for when it's really needed.

And the things get exceptionally cold, they've also been known to construct mud holes that add a little extra warmth, and not to mention shelter, which during the ice age would have been in bonus during any winter storm.

And to go along with Bermation, gators have another funky trick, as well, which consists of transforming their snouts into biological snorkels.

Even now, if water freezes over, and you live somewhere with gators, you might see a gator or two sticking their little snouts out through the ice, while the water around them freezes, and thus allowing them to stay a bit warmer, and allowing them to stay submerged without the need to get out of the water to breathe, and thus keeping them a bit warmer.

And while not as adapted for the cold, other crocs have some dandy tools as well that can help make cold spells a bit more tolerable, and this includes timing their days, as they will shift activities to make the most of the small pocket of warm weather, while planning nothing, so to speak, when it's gloomy.

Then during integral activities, such as basking in the sun, they're able to flatten their skin in order to increase surface area, and this increase amount of sunlight they're exposed to.

And we're looking at specific species, we see that some types of the mugger crocodile have been known to slither into burrows when it's cold, while nylon, salt water crocs take advantage of their usually larger environments by swimming into the deeper areas, where the water is less impacted by the cold air.

So clearly, it seems that this group has not won, but a few tricks to pull out when the going gets tough, and that's what makes them so crazy.

The fact that crocodilians have this huge array of tools, whereas some other animals only have one or two to help out.

And even with all this, there's still more madness to help them out in ice age.

I mean, take a look at a large salt water crocodile, for example, in an absolute unit, which is in a way over two tons, and with this size, you'd expect it to need to eat a cow every single day just to survive.

And yet, many times, adults and zoos, for example, are given less than 100 kilos or 220 pounds of it per, wait for it, year.

Yes, year.

220 pounds or 100 kilos per year, while an American person on their hand eats closer to a ton of food, despite being about 10 times smaller.

And this isn't some sick form of torture done by zoos, it's just that crocodilians have crazy slow metabolisms that allow them to survive without food for multiple months if need be.

And they also possess extremely efficient digestive systems, that leads to almost no energy from their food going to waste.

And as a result, during an ice age, when the mere thought of hunting in the cold sounds horrible, Crocs can just give a sigh of relief and stay in the nice warmth, thanks again to their metabolism, which will allow for some much-needed flexibility.

And to make the situation even better, when they do eat, they can still eat a poop load if they need to.

So unlike a human that may be starving, finds a giant carcass and then can only eat some of it, a croc can eat huge portions, with some species being capable of devouring half their body weight in one go, which is for reference like an American eating 14 full-sized chickens in one sitting.

So yeah, a lot of food.

And then to really seal the package with their already energy saving kit, crocodilians mainly kill in a fashion that's not very taxing.

Like, for example, let's say you find yourself an ice age and you need to go get some food.

Well, that's going to be a whole process.

You're going to need to gear up, get out there into the cold weather, trek around and hopefully find some tracks, track set animal, kill set animal, and then if you succeed at that, you don't have to bring the meat back to home base.

So kind of a convolved process, whereas in the crocodilians case, the food usually comes straight to them, like uber eats.

As again, they live in the water and all animals got a drink, allowing them to utilize ambushes, roll me a quick burst of power is needed, not much more.

And this was a huge deal in the colder days, as overall these adaptations allowed the group to save as much energy as they could, whereas other is so to operate at full capacity just to earn a snack.

And then to pair with the impressive ability that allows them not to eat for a long time, crocodilians have also evolved to be highly resistant in low oxygen environments, which doesn't just let them hold their breath for a long time, but thrive in more environments,

given them a wider range of places to live, which is nice when half of the world is already off limits due to the ice.

But what may have been a even bigger advantage over their ability to avoid oxygen, was their ability to beat up pathogens.

What I mean by this, is that crocodilians are not only resistant when it comes to taking damage, and being messed up, but they're also highly durable from an immune system perspective,

whether in aid and adaptive systems, being much stronger in the what's typically seen in mammals, for example.

And this is partially thanks to their blood, which contains very high concentrations of multiple antimicrobial peptides, that allow them to get rid of numerous bacteria, viruses, fungi, and parasite.

With it in fact being so potent that in one study where they introduced alligator blood to human blood, that was teeming with HIV, the HIV was completely eradicated once a crocodilian blood entered the scene.

And so, the advantage of having a powerful immune system is pretty obvious, but it might have been especially helpful during the ice age, as with the fall into global temperatures,

colder conditions can negatively impact immune systems defenses, resulting in it being a bit weaker than normal.

And crocodilians cannot only get over sicknesses quite quickly, but also general injuries as well, as their regenerative capabilities are almost on par with their immune systems.

Wounds they sustain not only clot exceedingly fast, but can also be observed fully healing within a few days, and they've also been seen to partial grow their tails too.

And this again is an advantage in general, but it's especially useful when everything is going to H.E. double hockey stick, or maybe the opposite of that?

Either way, when you combine this, with every other trait I've talked about, you realize that crocodilians survived essentially because they are superhuman, or super animal rather, and then also because they had prime real estate.

And truthfully, there are other reasons for this survival too, which I just didn't mention, as Crocs are really just one of the most metal creatures evolution has yet to cook up.

And there's a pretty good reason why throughout Earth's history, many animals are crock-like builds and lifestyles.

It's just that darn OP.

Thanks for watching, and until next time, on Extinct Zoo.