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Human evolution questions that keep me up at night

makes a compelling case: our ancestors weren't just passive survivors—they were adventurers who pushed further north than most modern humans realize, potentially crossing an ice-free land bridge when sea levels dropped. The evidence comes from two sites that challenge everything we thought we knew about ancient migration routes.

Beringia: The Land Bridge That Almost Always Existed

Most people assume the world has always looked roughly like it does today. It hasn't. During cold periods, sea levels dropped dramatically, forming a bridge between Russia and Alaska. Today, only 82 kilometers separate the two land masses. When that bridge formed, they were effectively one continent.

Human evolution questions that keep me up at night

What Stefan didn't fully appreciate is just how often Beringia existed. According to the National Park Service, this land bridge was present for roughly 80% of the last million years. The world as we know it—the ice-free oceans, the current coastlines—is the exception, not the rule. This changes everything about how we think ancient humans moved.

The Siberian Puzzle

Daring Urik lies 140 kilometers southwest of Yakutsk in Siberia, the coldest large city on Earth. Temperatures there have dropped to minus 64 degrees Celsius—roughly minus 83 Fahrenheit.

Archaeologists found lower Paleolithic stone tools at this site: simple bifaces and choppers that Homo erectus or similar ancestors would have made. These are literally just rocks with flakes removed in patterns—the number of those flakes matters, as does whether they appear consistently across multiple tools.

The dating is debated. Some argue the site is 260,000 years old; others push it to 400,000 years old. Either way, it's ancient.

What isn't contested is how far north this place sits: 61 degrees north latitude—roughly equivalent to half of Alaska's western coast. This is further north than almost any other Paleolithic site on Earth.

The implications are significant. How did hominins survive that cold? They must have had clothing, shelter, or at least animal pelts wrapped around themselves—"furry ponchos," as Stefan puts it. Were they capable of building shelters and sewing clothes? Probably not, but they could have used hides.

More importantly: how far was this from Alaska? About 3,300 kilometers—2,000 miles along the coast. Humans expand. That's what we do. If they were already that far north in Siberia, there's no reason to think they couldn't make it further into Alaska.

Critics might note that evidence for actual human presence in Alaska remains thin. The ice sheets covering Canada and much of North America during glacial periods would have been a barrier—though the land bridge itself was ice-free when sea levels dropped.

The California Mystery

The Cerutti Mastodon site in California is one of the strangest archaeological finds in North America. A mastodon skeleton found beneath a highway, with bones broken and tusks upside down in the ground—deposited in what appears to be a calm stream environment. That's unusual damage for a mammoth.

Some argue this proves archaic humans reached North America. The problem: no modified stone tools, no cut marks on the bones, and some teeth shattered as if hit hard—not something humans commonly did. It's odd enough that even Stefan admits it's an odd one.

On its own, it's not enough to prove any form of archaic human was in North America. But combined with other evidence, it raises questions we're still trying to answer.

The Bear Skull Cave

Stefan can't stop thinking about prehistoric religion and the origins of human symbolism.

It's strange that every culture has some form of religion—even people who aren't personally religious like Stefan add symbolism to everything: stories, practices, ideas. We're augmenting reality already through narrative.

Chauvet cave in France contains one of humanity's oldest artistic expressions. A bear skull placed prominently on a rock 25,000 years ago—not archaeologists moved it, but how someone left it originally. That's not accidental. Humans construct narratives around things we find odd in nature—we add layers of meaning to the world.

Stefan imagines humans entering caves feeling strange emotions in darkness, coming across animal remains and placing them ceremonially. What rituals got lost to time?

There's also a conicle black stone at a temple to Aphroditi in Cyprus—a people worshiping an unusually black rock. How long have people invested this rock with meaning? Maybe countless thousands of years.

How much of our reality is built by someone 10,000 years ago finding a strange rock and adding symbolism?

When Did They Disappear?

Another thought that keeps him up: when was the last archaic human alive? The last Neanderthal? The last Denisovan? Any other groups?

Of course, they interbred with us—so they're still here in our DNA. But when did the last one die?

"How much of what I do and believe is because someone 10,000 years ago found a black rock?"

Counterpoints

A reasonable counterargument: while Stefan argues Denisovans might have made it to Alaska, there's no direct evidence for any Arctic human crossing that wasn't much later. Homo erectus, Neanderthals, Denisovans—all without boats.

Another critique: the Cerutti Mastodon site remains controversial precisely because it lacks conventional evidence like cut marks or modified tools. The unusual bone damage could have other explanations—scavenging, natural processes, whatever buried the animal.

Bottom Line

Stefan raises two genuinely unsettling points that deserve more attention: first, that Beringia existed most of the time during the last million years means our ancestors had far longer to migrate than we assumed; second, religion might literally be "augmented reality"—the layer humans add on top of plain existence through story and symbolism. His biggest vulnerability is that he doesn't resolve whether archaic humans actually crossed into North America before modern humans arrived—the evidence remains ambiguous, and that's probably the right scientific position.

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Human evolution questions that keep me up at night

by Stefan Milo · Stefan Milo · Watch video

Did Neandertols or some other archaic human make it to North America? That's the first thing we're talking about today in just human evolution archaeological questions I can't get out of my brain. This is literally that meme where that woman's wondering what her partner is thinking about. This is what I'm thinking about in that scenario.

Did Neanderals or someone make it to North America? It's an interesting one. By the way, this is all coming completely off the top of my head today. I just feel like free flowing, freestyling as it were.

This is a question I've changed my mind on a lot. Usually when people talk about this, they're talking about the Seruti Mastadon, which was a masttodon that ended up underneath a California highway in some bizarre scenario. Strange things have happened to it. The bones are broken.

the tusk is upside down in the ground and yet it seemingly was deposited in quite calm environment like a stream or something gentle that covered the bones. Not the usual environment where this amount of damage can be done to a mammoth. So it's been argued that this is evidence for human activity. Problem is there's no modified stone tools.

There's no cut marks on the bones. Strange things are happening like some of the teeth have been bashed in and humans don't really do that so commonly like hitting at Masttoon's tooth so hard it shatters. That's a pretty hard thing to do. And it was uncovered by a huge piece of commercial digging equipment.

A digger. It was dug up by a digger. One big enough to build a motorway. So it's an odd one.

I'll freely admit it's an odd one. But on its own, it's not enough to prove that some form of archaic human was in North America. But there's another site I want to talk about called Daring Urik. This one is on the other side of the Pacific.

This place is about 140 km southwest of Yakutsk in Siberia. This is the coldest large city in the entire world. Allegedly, they've recorded temperatures up to -64.4° C. That's minus 83 Fahrenheit for my American viewers.

What can you say about that? That's bloody chilly. Shout out to everyone in Yakut. Rather you than me, but I'm sure it's lovely.

Here at this site during UriAk, archaeologists found what a ...