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Go to Brilliant.org/SciShow to check out their Math History course. [♪ INTRO]. During the later parts of the last ice age, the Americas were home to several different species of large cats.

These included familiar faces like cougars and jaguars, as well as the fearsome saber-toothed cats. But they were not the heavyweights of these cat-covered continents—that title goes unequivocally to Panthera atrox: the American lion. Scientists hope that studying these huge kitties can give us insight into the dramatic ways our world has changed in the recent past—and, in turn, help us predict how it might continue to change in the near future.

As far as extinct species go, we have a good amount of intel about American lions. Fossils have been found at over 50 sites from all over the continents, which date as far back as 200 thousand years. We even have skulls from multiple sites.

And the Rancho La Brea area of Los Angeles—home to the famous La Brea Tar Pits—has yielded the fossils of more than 80 individuals, including lots of skulls and other body parts to examine. All these fossils have taught us a lot about these animals. Like, for example, that they were really big.

The largest cats alive today are Siberian tigers, which max out at around 250 to 300 kilograms. Estimates vary for American lions, but it's generally thought that big males could grow well to over 400 kilograms! So they were some of the biggest cats ever, and possibly the biggest.

In Ice Age North America, the only predators that outweighed them were giant short-faced bears—which weighed up to a literal ton. Scientists have even extracted DNA from American lion fossils! And when they compared those sequences to other cats, past and present, they figured out that Panthera atrox split from the now-extinct cave lion over 300 thousand years ago.

So, we're pretty sure we know how they got to the New

World: most likely, a group of cave lions crossed the Bering land bridge from Asia into North America. Some made themselves at home up in the Yukon area, while others moved south, eventually becoming American lions. But even with all the fossils we have of these ginormous cats, there are some enduring mysteries—like, what exactly they were up to here. Paleontologists are somewhat confident that they roamed the plains.

That's because they had relatively long legs, which is similar to modern-day African lions that are specialized for the savanna, but different from many cats, including their cave lion ancestors. And they might have stuck to grasslands to avoid competition with the resident woodland predators: those terrifying saber-toothed cats. But what exactly they ate and how they obtained it are still unclear.

To look for answers, a 2016 study sized up modern-day predators and their preferred prey. From that data, they estimated that American lions could have regularly hunted animals as large as 900 kilograms — which would have included horses, bison, and even baby mammoths! And that's if they hunted solo.

If they worked in groups like modern lions do, the study estimated they could have taken down 6 thousand kilogram prey. That means giant ground sloths and even adult mammoths could have been on their menu! But here's the thing: even though the lions alive today hunt in groups, and there's evidence that suggests cave lions might have, too... we don't know if American lions did.

We know they had particularly large brains, even considering their size. But big brains don't necessarily mean social hunting. After all, modern-day tigers have bigger brains than lions, and tigers hunt alone.

Other research has noted that young American lion males are more common than young females in the La Brea Tar Pits, which suggests they were more likely to get trapped. And that could indicate that young males were roaming on their own while females stuck with a group, like we see in African lion prides today. So, maybe this is evidence of group living.

But it's hard to know for sure without finding, like, a perfectly fossilized pride, just like, covered in ash and waiting there for us to find it. Whatever they were doing, American lions went extinct toward the end of the Ice Age. The youngest American lion fossils anyone has found are around 11 thousand years old.

And that means, they disappeared around the same time as saber-toothed cats, mammoths, and most other large mammal species. The question of what caused all this extinction is one of the longest-running debates in paleontology. It's generally thought to be some combination of a warming climate and the global spread of humans.

But more research on American lions could give us some finer resolution there—like, why they didn't make it through when cougars and jaguars did. That resolution could help us figure out how to keep their smaller cousins from sharing their fate. Ultimately, that's why paleontologists put so much effort into studying creatures that disappeared long ago.

They hope they can learn from the past. That this learning means studying one of the most impressive animals to ever have existed? Just a bonus.

While we're on the topic of learning: if you're the kind of person who likes to learn new things, you'll probably love a subscription to Brilliant. Their website and app are designed to make STEM learning fun. And they have over 60 courses that can teach everything from introductory algebra to quantum physics.

Their new Math History course is extra cool. In it, you will learn math alongside the mathematicians that figured it out! So it's perfect for people who love learning about the past and brushing up on their STEM skills.

If that sounds like you, then you can head on over to Brilliant.org/SciShow to learn more. And if you're one of the first 200 people to sign up for an annual premium subscription there, you'll get 20% off! Which is a pretty nice deal. [♪ OUTRO].