-Are you ready to investigate?

-I am ready!

-Let's do it.

-I'm Emily Graslie, and I dig fossils.

This is amazing!

You can just, like, watch the whole tail coming out.

As chief curiosity correspondent for the Field Museum in Chicago, I've had the privilege of sharing my deep love of paleontology and the natural world through my YouTube series, "The Brain Scoop."

♪♪ But I know there's more to discover within our own backyards.

So I've headed back to the area where I grew up in the Northern Great Plains -- the heart of America's fossil country, on an epic road trip to rediscover our planet's past and unearth some clues about its future.

-How do we know where we're going unless we know how we got here?

-We've traveled thousands of miles, through billions of years of geologic time, seeing how life evolved from microscopic organisms to giant dinosaurs.

But they were no match for the asteroid that wiped them out and left traces of its impact across the landscape.

-Dinosaurs to no dinosaurs right across that little spot.

-Now it's time to see what not only survived, but thrived in the era known as the Cenozoic, the rise of the mammals.

-Dinos are done.

-Yeah.

[ Laughs ] -As we journey through its various epochs, we'll meet the bizarre creatures that evolved as the landscape began to more closely resemble the world we live in today.

-And I affectionately call it the saber-toothed camel giraffe.

-What?

So hop in, grab your rock hammer, and join me on this prehistoric road trip.

♪♪ ♪♪ -I wish more people were able to, like, take the time to understand what extinction means and how life has been able to evolve and diversify into so many different complex life forms.

I wish people knew!

Like, I just -- That's why I do the work that I do, because it completely changes the way that you move through the world.

We're back on our journey into the fossil record, heading toward a new geologic chapter called the Paleocene epoch.

The Paleocene followed immediately after the Cretaceous Period, which ended with the asteroid impact that wiped out 75% of all species on Earth, including the dinosaurs.

What did survive after that fateful collision set a new course for the planet's future.

-So, right now, we're in Eastern Montana.

We're standing in the very, very latest Cretaceous, and we're looking into the very earliest, earliest Paleocene.

-So these are the survivors of the extinction event?

-Absolutely.

These animals that were walking in this landscape right here had no idea what was about to hit them.

And then right there, we're looking at those meek survivors that inherited this fantastic world.

-Dr. Tyler Lyson from the Denver Museum of Nature & Science is on the hunt for some of the planet's earliest, furriest asteroid survivors.

-This is an incredibly rich microsite.

Microvertebrate assemblage.

So the material isn't complete, nice, articulated animals, but we have a whole diversity of animals.

We get a nice snapshot into what survived the extinction.

So when you find a good site like this and you work it and dig a big hole like we have done, chances are we'll find several new species that are new to science.

-That's exciting.

-See if we can just lift this -- Yeah, like that.

Look at that.

-Whoa.

-That's cool.

-What is that?

-That's part of a fish skull.

-Oh, neat!

-[ Blowing ] Ooh.

I'm always, of course, hoping for a mammal jaw.

What we're not seeing are all of those tiny, tiny mammals.

'Cause the biggest mammal that we would expect is about the size of a squirrel.

And that's the monster of the time.

So the teeth are just itty-bitty.

They're super small.

So what we'll do is we'll dig, and we'll find "the big stuff," even though it's all pretty small -- and then we'll take the dirt back to the lab, screen it, and then underneath a microscope, we'll pick out all the mammal teeth.

-That's amazing.

They're that small?

-They're that small.

They are tiny.

♪♪ -Tyler's tiny teeth had me curious about finding a way to see them up close for myself, so we're off to the University of Wyoming Geological Museum to visit Dr. Laura Vietti.

-Hi.

-Hey.

-Welcome.

-So good to see you.

Her job is to look after the museum's fossils, most of which are teeth.

Wow.

-Teeth are the hardest part of our body.

And so in terms of preservation, teeth tend to preserve the best.

And so all the bones will weather away either before deposition or after deposition, but teeth remain.

-There's only one problem.

These teeth are way too tiny to study with the naked eye.

Thankfully, Laura has developed a way for scientists to get a much closer look.

-I found an imaging microscope that is capable of taking focal stacks.

So you can see every part of the tooth in really good detail.

So, I've pulled from our collection a tooth that comes from the Paleocene, so just after dinosaurs went extinct.

And this belonged to a mammal called Plesiadapis, and that is closely related to primates, so our ancestors.

-Wow.

That's a tiny tooth.

-It's a tiny tooth.

So just for scale, this is 1 millimeter, this whole bar here.

So that is 1/10 of a centimeter just taken up by that frame right there, so it's pretty small.

-That's amazing.

-So it's a really powerful instrument for giving us high resolution, high magnification over a larger area.

-These early mammal teeth may be small, but the amount of information they contain about the Earth's past is huge.

-Teeth are the most informative part of the body.

The tooth shape itself is really indicative of the diet.

And so we can learn what the animal is eating.

We can look at little micro scratches on the tooth surface, and that will tell us about the last meal that the animal was eating.

-What?

-Yeah.

No, it's pretty cool.

And that also tells us about the environment that the animal was living in.

The size of the tooth can give you the size of the animal.

You can tell what age the animal was often based on the tooth.

-You're looking at microscopic clues, essentially.

-Microscopic.

Yeah.

-And able to, like, take those and extrapolate out and reconstruct entire extinct environments?

-Absolutely.

-How do you do that?

-[ Chuckles ] A really, really good microscope and years of research.

-Yeah.

I'm leaving the University of Wyoming with a larger appreciation for the smaller things and am excited to learn more about how mammals diversified as we head deeper into the Cenozoic era.

Our next stop proves that mammals were about to get way bigger and weirder.

And after eight weeks on the road, we're all getting a little bit wacky ourselves.

-[ Sighs ] What do you call it when a T. rex farts?

-[ Laughs ] What?

-An ex-stink-tion.

-Oh, gross!

What did one continental shelf say when it ran into another one?

My fault!

-Yeah, I was just thinking, like, "My fault!"

"My fault."

-Everyone cares about geology, in one way or another.

-Want to know why?

-Why?

-'Cause geology rocks.

-Nope.

Oh, my God.

This road trip is -- We have three more hours of driving.

♪♪ Not far from where I grew up in Western South Dakota, Badlands National Park is one of the best places in the world to study fossil mammals.

As far back as the 1840s, early settlers to the area were finding fossils eroding out of the buttes and sending them to universities on the East Coast for study.

Paleontologists have been excavating and researching these ancient environments ever since, and for good reason.

More than 75 million years of Earth's history are recorded in these painterly rock layers.

But we've come to learn about the sections that preserve the epochs between 37 and 28 million years ago, a time when this region was a hot, subtropical forest, and later, a savanna.

We're meeting up with Ed Welsh, paleontologist and park ranger at Badlands, to learn more about the fantastic mammals that once roamed these ancient plains.

What are some of the highlight animals or other fossils that can be found in some of these units?

-Alright.

This is where it gets fun.

We have a core set of Badlands animals that kind of show up throughout the units, and they might be species variations as we go up through time.

We get the first dogs here.

-The first dogs?

-The first dogs.

-From here?

-From here.

-Everyone must be so happy about this.

-[ Laughs ] A lot of people don't know about it.

They don't realize it until I start yapping about it.

But as we go through time, there are unique animals.

So, if we are in the Chadron formation, our lowest part of the Badlands, we get the giant Brontotheres, these big elephant-sized guys with a slingshot horn on their nose.

They look like a rhino.

They're related to rhinos, but they might be closer to horses.

These animals like wet and swampy conditions.

And one of the more common neighbors that we find alongside Brontotheres are alligators.

-What?

-So alligators were alive here.

Of course, they don't live here now for obvious reasons.

-Little dry.

-It's a little dry.

And then we have these river channel deposits, and we find this weird animal called Protoceras, and I affectionately call it the saber-toothed camel giraffe.

-What?

-Because they are such a bizarre-looking animal.

They're built like little camels.

They got camel-like teeth.

Four toes in the front, but the two weight-bearing toes are the ones that are bigger and noticeable.

They got a short neck.

The males will have six horns on their head -- two on the cranium, they get two above the eyes, and then two on the nose, and also a pair of fangs.

-What?

-Pair of saber teeth, like some species of deer do today.

-It's a wacky-looking animal, though.

-It's a wacky looking animal.

Very wacky-looking animal.

So that's why I affectionately call it the saber-toothed camel giraffe.

-It definitely paints a picture.

-Yeah, 'cause these things are all dead.

We've never seen them before.

So, how do you explain that?

♪♪ -One person helping to draw a better picture of these bizarre ancient animals is Dr. Darrin Pagnac of the South Dakota School of Mines & Technology.

He's been working on fossils here in the Badlands for more than 20 years, enduring the park's often unfavorable climate to do so.

It's toasty town out here.

-It is.

It's gonna be a hot one today.

-Yikes.

It is early in the morning.

We are sweatin' buckets.

-Yes, we are.

-It's not even remotely as warm as it's going to be out here.

-Nope.

-And these are the conditions that you work in.

-Yes.

Yep, they are.

We work in conditions of high temperature, high wind.

-My next question is, why do you do it?

[ Laughs ] -Because it's awesome.

Because it's fantastic.

Plus, this.

-Yeah.

-Look at what we get to see and find.

This is the skull of an animal called Leptauchenia.

It is a small herbivorous mammal that is very, very common here in the Badlands.

We don't have any really equivalent organism alive like it today.

But the best description is somewhere between -- Imagine a sheep with a slightly more elongate body, a little more stumpy legs, and no wool.

-And it's just exposed here right at the surface.

-Yes, it is, yep.

It was discovered by a visitor a few summers ago.

And this is how the bones erode out here in the Badlands.

-And it's important that this specimen stays here, right?

If a visitor came across this and was like, "Oh, I'm going to take this," and removed it and took it to the visitor center instead, you're losing a lot of valuable information that way.

-Yeah.

I think more importantly, this is the public's.

This belongs to the public.

And so if that individual would be taking this, they would be stealing from the American public.

And that's not right.

-No, yeah.

Don't steal, folks.

-No, not at all.

♪♪ -Is poaching of fossil materials a problem in the park?

-It's actually a very serious problem in the park.

Because we have so much material and we're so well known for fossils, poaching in the park is big business for some people.

And people that illegally collect here in the Badlands can contribute to that.

We allow people to walk off-trail, so people can get out in that resource and explore and have fun doing it.

But part of that means they have the opportunity to find stuff that's coming out of it.

-Fossils.

-Yeah.

If they're finding fossils, we want to try to educate them as best as we can so they know how to behave around fossils.

-Today, rangers educate visitors to the importance of reporting their fossil finds to park officials.

And with so many extra pairs of eyes on the ground, the efforts have resulted in some phenomenal discoveries, including one from right under their noses.

So, whereabouts did you find this fossil?

-Right about here, so really close to the visitor center.

-Kylie Ferguson was a third grader when she visited Badlands on a vacation with her family in 2010.

Years later, that eventful day remains fresh in her memory.

-The day I came, it was a fossil junior ranger program.

And they told us what fossils looked like and what to look for, what kind we'd find here.

And then they released us to go look for fossils.

That's when I found it.

-Do you remember what you initially saw?

-I saw a little white, shiny, crescent-moon-shaped thing, and I wasn't sure what it was, but it definitely looked like a fossil.

And originally, they thought it was a sheep-like animal, but then they saw sabers, and they realized that was definitely not a sheep.

And so then they excavated it and got it out, and that's whenever they realized it was a saber-toothed cat.

-Did they call you?

Did they, like, pick up the phone, and they're like, "Yo, Kylie!

That thing you found!"

-Yes, they were extremely excited.

And they're not the most rare animal, but the condition mine was found in was very rare.

-At just 7 years old, Kylie Ferguson made an unusual discovery.

-I found a saber-toothed tiger skull.

-This fossil is very unique because of the incredible preservation of the skull.

We just have so much detail preserved.

-A huge discovery made by a little girl.

♪♪ -Kylie's fossil skull belongs to an animal called a nimravid, which is distantly related to true saber-toothed cats but no less ferocious.

It's been a decade since her discovery.

And in that time, this remarkable specimen has been collected, scanned, and studied by paleontologists, whose research has led them to reconstruct its final moments.

-So, we think this thing was attacked.

Well, there's a little hole here for the optic nerve.

That same hole is here, but there's another hole right next to it, which fits an attack from the side.

It got stabbed in both eyes.

-Oh, no.

So you didn't just find an amazing and immaculate skull.

You actually stumbled across a murder mystery.

-Yep.

And this is a 32-million-year-old murder mystery.

-Cold case.

-Yeah.

[ Laughs ] -Did this experience give you sort of an impression that science is something that anybody could do?

-Yes!

A 7-year-old!

A 7-year-old finding one of the best preserved cat skulls in this area.

-I think that's great, and I think it's awesome that you had gone through the program and, like, had your training.

You knew what to do, and it's resulted in this amazing scientific discovery.

I think that's really awesome.

-Me, too.

-Where one geologic formation ends, another begins.

And our journey is propelling us further ahead in time to the Miocene epoch, around 20 million years ago.

[ Car horn beeps ] Agate Fossil Beds in Nebraska might be one of the least visited national monuments in the United States due to its remote nature, but many people, perhaps unknowingly, have encountered its paleontological gems.

Slabs of fossil beds removed from Agate can be found in museums around the country.

But it's definitely worth going a little out of the way to visit them in person.

It's really a remarkable place for fossils from this region and from this time period.

-Right, right.

A lot of people would think this is in the middle of nowhere, but it was at the epicenter of mammal paleontology in the early 1900s.

-Yeah.

-When these were discovered, paleontologists from all over the country were excavating here trying to understand what was going on in what we now call the Miocene epoch 20, 23 million years ago.

-Back then, a drought ravaged this part of the country, and countless ancient rhinoceroses and miniature camels congregated in the area in search of water, ultimately succumbing to dehydration to be preserved in mud pits by the hundreds, along with predators like bear dogs, who came looking to snack on struggling prey.

In addition to the fossil beds found at Agate, this site is well-known for other fossils -- mysterious, spiral-shaped columns eroding out of the prairie that stumped early paleontologists for decades.

♪♪ Alvis, you mentioned that this is called a daemonelix.

What does that word mean?

-It's actually a Latin word, means "devil's corkscrew" -And that is talking about the spiral in particular?

-Right, right.

The paleontologists came out here and discovered these and said "What is this?

This is the strangest looking thing."

So they start digging it out, and they discovered that it was a spiral indeed.

Leading paleontologists thought this was a taproot of a tree.

So one day, grad student, poor grad student, he dropped a hammer and cracked it open.

And guess what they found.

They found some bones in there!

Say, "Whoa, this is not a taproot, because you can't have a fossilized animal in the taproot.

That just doesn't make sense."

So they had to change this theory.

So it was really cool, that an accident led to this discovery.

And so this is, believe it or not, a really cool burrow of something called a Palaeocastor.

And that is this ancient beaver.

Most beavers nowadays, you think they go in water, right?

-Aquatic, yeah.

-Yeah, they're aquatic.

But this was a dry-land beaver, and it was a little bit smaller than the big beavers that we have nowadays.

-So you had, like, this land beaver that is making this spiral burrow by chewing a spiral down into the ground.

And then there's maybe a big flood event that traps the beaver in the bottom chamber.

-Unfortunately, yes.

-Everything else gets filled up with sediment and silt.

Over millions of years, that fossilizes, and then as these looser sands get blown away, you're left with just the structure of the burrow.

-Right.

-I just think it's really great that this is a site that you can walk right up and be this close to history.

-I love it.

♪♪ -I like to drive through this landscape and think about the North American cheetah.

A lot of that Ice Age, Pleistocene megafauna went extinct at the end of the last ice age.

Yeah, cheetahs.

There used to be cheetahs here, and American lions and short faced bears.

Wooly mammoths.

♪♪ We're entering the Pleistocene epoch, commonly referred to as the Ice Age, which lasted from around 2.5 million to 11,700 years ago.

During this time, the planet was going through glacial cycles, and the ebb and flow of ice sheets allowed for the global movement of animals, as well as people.

Early humans had evolved toward the beginning of this period, and our species, Homo sapiens, was living in Africa around the same time that our next stop represents, about 200,000 to 100,000 years ago.

[ Car horn beeps ] At the Mammoth Site in Hot Springs, paleontologists and volunteers have been working to excavate the depths of a sinkhole where more than 60 of these ancient elephants and their neighbors met their eventual doom.

In the decades since its initial discovery, the Mammoth Site has been enjoyed by countless visitors and school groups, including me, as a kid in the '90s.

Growing up in this area, I feel like maybe I took it for granted a little bit, but this area really is unique.

-You don't find it where elephants have come in and got trapped in one place, so that makes it kind of unique.

-Dr. Jim Mead is the Director of Research at the Mammoth Site, where the ongoing excavation has been made accessible since its accidental discovery in the 1970s.

-There was a hill.

Contractor's coming up, and he's going, "I want to build some houses here.

Let's get rid of that hill."

And as he takes down the hill, some bones are starting to show.

So, this would be, you know, July of 1974.

And they ask us, "Could we come and take a look?

Are these mammoths?

What are these things?"

So we showed up, and it was kind of like, "Yeah, they're mammoth.

You might have two or three, maybe five."

And so we start excavating, and we take out a bone.

There's another one below.

Take out another one.

There's another one below it.

We go, at some point, we've got to stop.

-After two summers of finding fossil after fossil, the landowner realized this discovery was too unique to be lost to a housing development.

Instead, they built the Mammoth Site museum and research facility to share the incredible story of how these animals came to be preserved.

-These mammoths were kind of wandering around.

They find this seemingly placid body of water, and they go in for a drink, and they get stuck.

-And as they go in, then they can't get out.

So they're going to swim around, and they're going to drown, and they're going to float and bloat and sink to the bottom, and we have them.

-How many mammoths have you found in this pit?

-Based on tusks, okay -- So every elephant, every mammoth will have two tusks.

We've recovered 122 tusks.

-Wow.

-Now, we haven't dug the whole site yet.

I'm going to take you down into the pit.

This is our most complete skeleton.

So now you're about 35, 40 feet underwater.

♪♪ -Claustrophobic isn't the word for it, because there's all this open space above us, but you do get this sense of that -- -There's a lot of water.

-Can you point out some of the anatomical features on this skull?

I think it's so interesting that what you might think is the eye hole isn't the eye hole.

-Right.

Well, the eye hole is right here.

So this one is kind of, out of its left eye, is looking at me.

And of course that trough there in the middle is where the trunk hangs down.

Definitely.

And you got the two tusks coming out.

And the tusks are telling you that you really do have an adult, okay?

This animal's probably 20 to 30 years old.

-Wow.

What is the value in keeping these things in the place where you found them?

-I think it's the education side of it, of getting the younger kids excited and to get them down there and have them work on it.

-Not a lot of people get that opportunity to go out and visit an active dig site.

This is an active paleo dig site... -All year long, yeah.

-...that is open and accessible to anybody who can make it to Hot Springs.

We're departing our journey along the geologic time scale, but the voyage into understanding how our world is shaped today by studying the fossil record isn't over yet.

On this trip, we've seen examples of the power of fossils -- how they inspire the pursuit of scientific discovery and innovation, and how they shape our interpretation of the past.

So, what would our world be like without the insights fossils provide?

♪♪ Local rumor has it that just down the road from the Mammoth Site is another area home to unique fossils.

But without any signs or directions, it's one of the more difficult locations we've had to try and find.

So, we're heading north now.

And then there's a point where the highway turns sharp east and then north again.

-So, we have a map from the BLM.

-Yeah.

-So you're gonna look up to your left.

-Okay.

-There's gonna be a bridge.

-There's going to be a bridge.

-[ Laughs ] -So now -- Here's the bridge.

-Here's the bridge.

-Is that the pull-out?

-No, it's after the bridge.

♪♪ Fossils... [ Vocalizing indistinctly ] -So this is the pull-out.

-Yes.

-There's no marker.

It's just, like, a dirt road.

-Yep.

-This is it?

-Yep.

-We're here.

-It's got to be it.

I'm assuming it's it.

Yeah.

-Well... we made it.

This area of rolling hills and plains was once Fossil Cycad National Monument, a site dedicated to its abundance of Cretaceous-age petrified plants.

But there are no signs, boundaries, or any indication that something of historical value or scientific importance took place here.

In fact, it's one of only a handful of national monuments in American history to be decommissioned by the Park Service.

I wanted to know more about the history of this monument, so I headed over to the South Dakota School of Mines & Technology in Rapid City.

Hi.

I'm meeting Sally Shelton, who oversees their paleontology collection and has more on the story.

-Fossil Cycads is an early plant.

Relatives of this are still alive today.

If you see anything, like, in a bank lobby that looks like a pineapple with ferns sticking out of it, you're probably looking at a cycad.

And for some reason, one of the best deposits of them ever found was right here in South Dakota.

A lot of people were very interested in these.

One was a paleobotanist at Yale named G.R.

Wieland, who came out in the '20s.

He had a vision of this being Fossil Cycad National Monument.

Dr. Wieland got tired of waiting for this to develop and actually went out, loaded all the fossil cycads he could find on the surface into boxcars, and took them back to New Haven, Connecticut, to Yale.

-How many fossils are you talking about?

-Thousands.

-Thousands?

Thousands of these?

-Thousands of these.

People are very funny when it comes to objects and specimens and things like that.

-Is Wieland the reason for the formation of Fossil Cycad National Monument, as well as for it to be decommissioned?

-Yes.

Yes, both.

-Isn't that ironic?

-Both.

He created it, and he took away any reason for justifying it.

If you had one kind of fossil that you liked, and you found the world's biggest treasure trove of them, how would you react?

I ask that question of a lot of people, and everybody responds differently.

Some people would rather leave them where they are in-situ.

And some people would scrape up the entire collection and take it home with them.

♪♪ -Like Agate Fossil Beds or Badlands National Park, at one time, this land was destined to be set aside in part to preserve the fossils found here.

But because of actions taken in the past, untold numbers of people today will never get to know about these fossil cycads and the ancient world they represent.

To me, that feels like a preventable loss.

So what should ultimately happen to a fossil, and who gets to make those decisions?

Science could use quite a bit more empathy.

I think paleontology could benefit from taking the time to sit and talk with other people who have a different world view, who have a different interpretation.

You know, for a long time, the mentality in paleontology was to find a fossil and to take it out and take it into a museum, and that's really when that fossil begins to achieve its own value -- when it can be studied and written about and published in scientific journals.

And there are other people who think that fossils should remain in the ground, for reasons that are based in long histories of cultural and spiritual significance.

And I'm not in the business of saying that one of those world views is superior to the other.

I think it just requires that we all keep an open mind and are willing to have these conversations in good faith.

There's one person I've been eager to talk with about these moral complexities -- Dr. Lawrence Bradley, whose research examines the history of academic paleontology and its intersection with Native American tribal lands in this part of the country.

In your research, you visited a lot of natural history museum collections and looked at fossil specimens that had been collected from Oglala Lakota Sioux tribal lands seemingly without permission or consent from the tribal communities, and then taken to museums.

What inspired or motivated you to pursue this research?

-I was raised by Oglala Lakota.

I wanted to be an ambassador for the Native Americans in science.

And I wanted to do a paleontology survey on the Santee Sioux Reservation, so that way, they'd know where their fossils are located so they could better manage them.

I humbled myself before the tribe, attained permission.

And then I went to a Society of Vertebrate Paleontology meeting.

And someone told me they were going to collect a plesiosaur near Creighton, Nebraska, within the Santee Sioux Reservation jurisdiction.

So I went back to the tribal council and so forth and asked them, "Hey, did you know they were going to collect a plesiosaur?"

They said no, they never knew anything about it.

Then in May of 2003, I open up the front page of The Omaha World Herald, and I see some Nebraska Department of Roads personnel on the front page shoveling dirt collecting a plesiosaur.

And that is when I had a eureka moment, and I thought, "Well, if this is this incident, then how far back in time has this occurred?"

And that's where this research topic came to me, and I started to see it was started about the 1840s... -Wow.

-...all the way to modern-day.

-So there is a historic precedent for excluding Native American communities and reservation communities in academic paleontology.

And this was what you wanted to research.

-Yes, yes.

Most definitely.

Land, timber, minerals, coal, so forth, have been dispossessed from tribes.

And this is where you have to, you know, make a case that fossils, vertebrate paleontological fossils, have also been dispossessed from Native Americans.

And one of the things that universities or museums would do when they collect fossils, they would say it comes from a certain county, certain state, and they would never say it came from a reservation.

And that's -- You know, they should put that on the plaque or whatever's describing the fossil, so forth, to be complete.

It's where we have to create a paradigm shift in the field of paleontology for them to acknowledge the past.

-Let's say a museum collection manager, someone in vertebrate paleontology, is opening a drawer in their collection, and they come across material that appears to have been collected without permission or meaningful consultation with a tribe.

What would you recommend that museum does with that material?

-I do to a certain degree advocate for them to be returned to the tribes.

But it's not up to me.

It's up to the tribes themselves and how they think they should receive those.

Above all, be transparent and acknowledge the past.

They need to slow down and understand that there's an ethical and moral aspect to everything that they should be doing in the way they approach collecting any fossils or any type of paleontology study on a reservation.

-Do you have examples of positive inter-agency collaboration between museums or U.S. federal government offices with tribal communities?

-I understand perhaps the South Dakota School of Mines are doing some good things with the tribes, working with the Oglala Lakota College.

-Historically, School of Mines, Museum of Geology had been collecting in tribal lands.

And now you are being transparent about that and saying, "Listen, we do have this material, and it may or may not have been collected with meaningful consultation with the tribe."

Do you work towards repatriating some of that material and giving it back to the tribal college?

-Yes.

We had two students do an inventory of everything that we have packed from the South Unit of Badlands, which is co-administered with Pine Ridge.

As far as I know, that's the first tribal inventory of fossils that we have done.

So what I want to do is expand that to everything we have that's ever been collected from Pine Ridge to provide that as you would provide a NAGPRA inventory and to see what steps they want to take next.

We advertise that this is a resource for educating our students.

This should be a resource for educating everybody.

It should be a resource that everybody can draw on, and if they're tribal and they're drawing from tribal lands, then students there should be the first beneficiaries, not the last.

-Why do you think it has taken so long to build these relationships?

-I think it was a lack of respect on the museum's part.

I think we still have that perspective that somehow our story is more important than their story.

And I think that that's absolutely wrong.

If we're working on their land, we need to respect their beliefs, and we need to bring them into the decisions that we're making about, what do we do with fossil material?

How do we store it?

How do we study it?

-And going forward, what is your hope for these collaborations?

What's your vision for the future?

-Oglala Lakota College started a paleontology program a few years ago.

So I would like to see the paleontology program at Oglala Lakota College and other tribal colleges go forward so that people, especially people who have grown up traditional or who have traditional values, can communicate with the scientists that there is another side to the story, there are other values going on, and that they actually take control of the materials that were removed from their lands.

♪♪ -It's important to realize that this is just a really small part of the tribal collection.

Most of the fossils are now housed at the School of Mines.

And I think it's a good way of starting to think about bringing back, collaborating, and sharing.

-This seems like a really positive step in the next direction, not only to make these resources available to the tribe, but also maybe to inspire the next generation of students here at the college who may have an interest in paleontology.

-Oh, absolutely.

I think given the history -- You know, we've had a history of theft.

Really, the most important part of this repository is it starts to provide a basis or a sense of security for tribal members.

And this is how we start to heal as a community, is we say, "Hey, there were mistakes in the past."

You apologize.

You move forward.

You try to find those spaces of, where can we connect?

Where can we move forward together?

♪♪ -You really begin to look at these maps of these geographic areas, and you begin to really consider what it means to have borders and where those borders have been created, because they're superficial.

They're not created by any geologic boundary necessarily.

They're created artificially on paper.

And they're legal boundaries.

And they have legal implications.

So when we think about fossils as resources that have power, that are academically or educationally significant, that may have a commercial value that can essentially make people a lot of money, the stakes just become a lot higher than just looking at fossils as neat things or, like, cool relics of the past.

They really are weighted.

♪♪ To learn more about how tribal communities manage their fossil resources, I'm on my way to meet Sonya White Mountain, who is the director of the Standing Rock Institute of Natural History.

The Institute's goal is to find and protect fossils found on their tribal land and build a collection to educate their community and visitors about the fossils' historical, cultural, and educational importance.

-We -- Our tribe, I should say, is the first in the nation to create their own paleontology code and to have a paleontology department, so we're pretty proud of that fact.

-And the code is sort of like an outline or guideline for what one should do if they find a fossil or if they're interested in looking for fossils out here?

-Exactly.

It helps to provide for not only the protection of the specimens, but the protection of the tribal members themselves, so that if anybody does find anything, it's out there.

It's in writing.

It's a legal code saying that it belongs to the tribe of Standing Rock.

-So in addition to having this paleo code for academic researchers, you also have this educational resource so that members of the tribe can learn about the paleontological resources within your community, as well.

-We had a kindergarten group just about a month ago.

And one of the little ones comes in and starts growling.

-[ Laughing ] Oh, yeah.

-And he said, "I love dinosaurs."

And he starts naming off all these dinosaurs.

And that's exciting for me because, you know, in this area, it is poverty stricken.

There's not a lot of options.

But to find out that Standing Rock has so many fossils that are found right here on our reservation, it's exciting.

We get to tell these kids, "This is here.

This is a part of your culture.

It's a part of your history."

-Has it been challenging to get support for the institute from the tribe?

-It actually has.

It's been a huge challenge.

I think the reasoning is that paleontology is not a vital program.

It's not something that provides day-to-day assistance like, I guess you could say, like social services, something like that.

If they don't keep something like this going -- I mean, so many of the narratives and the tales through our culture include these very things that we have on display.

It's not just about newsworthy items.

It's about educating our people.

♪♪ -As someone who's grown up and loved museums and has worked in a museum for a long time, to be able to really stand back and critically think of the ways in which academia and museum science hasn't been respectful or inclusive of alternate perspectives or different world views or even boundaries, that has all been an intellectual process and an emotional journey for me personally.

It feels like a very small victory, not for me, but for this conversation to be happening.

♪♪ Paleontology as a field of science studies worlds and ecosystems of the past, but that doesn't mean there aren't any present-day applications for this work.

Through paleontology, we begin to understand how the implications of our actions today can shape our future, whether that's the decision to protect fossils as valuable, nonrenewable resources, or by looking at how ancient ecosystems change over long periods of time, to get an idea of where we might be heading.

We're on our way to meet up with some researchers who are camped out at their field site, located on a cattle ranch and wind farm in Central Wyoming.

I've never been so close to a wind turbine.

We are right underneath these things.

Look at how big those blades are!

This is wacky, man.

Yeah.

Did not expect this even this morning when I woke up.

And I'm like, "Yeah, we're gonna go to the campsite tonight with Ellen Currano and the team."

Rolling in at sunset.

♪♪ This group of scientists is finding and studying evidence of a past climate change event known as the Paleocene-Eocene Thermal Maximum, or PETM.

The PETM is a critically important climate-change event because, although it occurred over 56 million years ago, it's the best analogy we have for understanding the long-term implications of today's global climate change.

Scientific data collected from many sources -- greenhouse gas emissions, temperature records, and ice cores, among others -- confirm that the rapid warming of our planet today is being caused by human activities.

But it's thought the PETM was caused in part by volcanic eruptions in the world's oceans, which released huge amounts of greenhouse gases into the atmosphere.

Dr. Ellen Currano is a paleontologist at the University of Wyoming specializing in ancient plants, and has spent years studying evidence of the PETM in the fossil record.

-This is a site that we have from this Paleocene-Eocene Thermal Maximum.

We have these leaves that are preserving what the vegetation was like during that event.

Over the course of about 10,000 years, a bunch of carbon got burped into the atmosphere.

Carbon's a greenhouse gas, so it got warmer, probably about 5 Celsius, 8 Fahrenheit.

With temperature change, the moisture's going to change.

Precipitation's going to change.

-The entire environment changed, in terms of the plants, which also probably indicates that other things were changing along with them.

-Absolutely.

So, Earth changes.

You know, here we are in the sagebrush and grass and wide-open environments with wind.

And 56 million years ago, there were palm trees and crocodiles and turtles running around here.

So, Earth changes.

But it doesn't change as fast as we're changing it.

If we burn the remaining fossil fuel reservoirs, we're probably releasing about the same amount of carbon into the atmosphere as was burped out during the PETM.

Humans are an unprecedented force of nature.

In the PETM, that carbon release happened over, at minimum, 1,000 years, at maximum, say 10,000 years.

Humans are doing this over decades, so tens to hundreds of years.

-Wow.

-And so what we're doing is 10 times faster at minimum than what happened during the PETM.

♪♪ -By comparing fossil leaves from the PETM to what we know about living plants today, we can begin to understand how high, sustained carbon levels in our atmosphere will impact our planet's plants and animals now and into the future.

♪♪ -Up here, we try and look at how the plant communities, how the insect communities changed across this time interval of the PETM, and so, understanding pre-PETM communities, how they were impacted by the hyperthermal event, and then what they looked like afterwards.

-Wow.

-Pretty nice fossil.

You can see nice vein detail, nice veins here, really nice insect damage right here, these holes that are right here, these circles.

And you can also see if you go down from the top how it's feeding right there.

-Oh!

So you can actually tell that this was being chewed on by somebody?

-Yes.

-A long time ago.

-Yes.

-That's amazing.

-Yeah!

So, everybody gets all hyped up about dinosaurs and mammals and everything else, but if you don't understand what the vegetation was or what these insects, what these animals were eating, it's really hard to understand the changes that a region might go through and how that then might impact the animal -- you know, the very charismatic megafauna that we tend to love.

♪♪ But you have all this amazing cuticle.

This place is so cool because of that.

-It's very windy.

Yeah.

It's gusty!

-We are at this amazing leaf site.

So, this is about 2 million years before the Paleocene-Eocene Thermal Maximum.

So, this site provides a baseline for us to understand what the vegetative landscape was like before we have this greenhouse gas event.

Tons and tons of information, just blowing in the wind.

[ Both laugh ] I know.

It's like, here today, gone tomorrow.

Ooh.

This is a cycad.

-Yeah, look at this.

-That's a cycad leaf with the actual leaf tissue right there.

And in that leaf tissue, it preserves all kinds of environmental signals.

So it can tell you how much carbon dioxide there was, how dense the forest was.

It can tell you where in the canopy or where in the forest that plant grew.

So, all these leaves came out of the forest -- some kind of forest, right?

There's big leaves that we're finding.

But how dense is that forest?

How many stories of vegetation are there?

And that's a really important question to answer, because vegetation and the structure of vegetation can tell you a lot about the rest of the ecosystem.

-So what did happen during this ramp-up of CO2?

What happened to the canopy?

-So, just before the event, things start getting warm and wet, and then the canopy starts increasing in density, probably like a tropical rainforest -- very, very thick and lush.

The CO2 turns on, and then boom, just like that, we lose about 75% of the canopy cover... -Really?

-...when the event turns on.

-The PETM event, do you think that life here in this area in Wyoming or even life globally was able to adapt because it was a "relatively" slow release?

-In part, yes.

So, we believe this is a very slow release, over a 3,000- to 6,000-year time period, whereas today, we're releasing the same amount in 10 times that rate.

Today, we've seen change in overall vegetation in the globe.

There's more green leaves growing on Earth today than in the last 30 years, just because of the CO2 that's being emitted.

-Today.

-Today, yeah.

-Wouldn't most people think that that's a good thing?

-Yes, right?

Everybody thinks, for agriculture, it's great.

We can grow more crops.

We can grow more food for people.

But one thing that we know is that when there's more CO2, there's less nitrogen in the food.

So food is less nutritious.

-You're sort of informing our perspective of evolution or life on earth today and what it could look like in the future, based on studying how it was in the past.

-Absolutely.

How do we know where we're going unless we know how we got here?

-I think a lot of people might look at paleontologists and think that they're stuck in the past and that they're somehow lost in an ancient world that has no analogy for today.

And I think just the opposite is true for that.

I've seen and experienced a real sense of urgency in the kind of work that's happening out here studying climate change.

Work that these scientists and paleontologists and geologists are doing is contributing to a growing body of knowledge of what's happening to our planet today.

And just to be able to witness that and participate in that has been something I'm never going to forget.

Understanding today's rapidly changing climate isn't the only urgent research area with ties to the fossil record.

[ Car horn beeps ] Over in Montana, lurking in the depths of the Yellowstone River, lives a prehistoric relic, a fish whose ancestors swam in this region's ancient waters alongside T. rex and Triceratops tens of millions of years ago.

Fossils of its distant relatives discovered nearby show how little these animals have changed over millions of years and reveal how some animal lineages are able to endure through the eons -- that is, until humans arrived.

Because of habitat destruction over the last century, this species of fish, the pallid sturgeon, is now endangered.

-There's 40-some species of fish in the Yellowstone.

-Is the pallid the most endangered of all the species here?

-Yeah, for sure.

You know, there's only about 100 of those, you know, wild adults left.

So, I think we'll just go down to a spot that's been decent for fishing and run a few nets and see what we see.

-Fisheries biologist Mat Rugg leads a team who are monitoring the pallid sturgeon in the hopes they can help save this species from extinction.

What are some of the things that have contributed to the decline of pallid sturgeon?

-Really, so, basin-wide, probably the largest thing has been just the construction of the main stem dams and some of these lower head irrigation dams.

It's a species that evolved to, you know, require large reaches of river to complete all their life cycle, swim upstream and migrate and spawn.

And then their free embryos drift downstream and develop.

And with the breaking up of the long reach of the river, that life cycle has been blocked off.

-Oh.

-Oh.

-Ooh.

Something jumped.

Mat and his crew keep tabs on all fish populations in the Yellowstone, so any fish that we caught in our nets had to be measured and weighed.

Alright, that was all of them.

Go back out?

-Yeah.

-Alright.

Let's go.

Got to find that pallid!

-[ Chuckles ] ♪♪ -So, we drop the line in for the sixth time today, and not a single pallid, which I guess makes sense considering how rare they are.

But we're still hopeful that we'll find one.

Giving it another go.

On our last check of the day, we finally got lucky.

♪♪ -Yep.

-Nice.

-Yes.

-Here's a pallid sturgeon for you.

-Yeah.

-We're going to go ahead and work it up now, get length and weight... -Okay.

-...and kind of work our way through it here.

-Wow!

Oh, boy!

-Yeah, great fish.

-As part of the efforts to save this species, the vast majority of pallid sturgeon today are bred in hatcheries and later released into the Yellowstone.

Taking a DNA sample will allow the scientists to figure out which is the case for this one.

Mat inserts a radio tracking device so he can continue closely monitoring this sturgeon's movements over the next few years, which provide insights into the species' migration patterns and population numbers.

You really are doing fish surgery.

-Yeah.

We're going to take blood.

-Wow.

I'm just amazed that there's all of this advanced technology that's going into tracking this fish and raising them and trying to re-propagate them.

Whether the pallid sturgeon's population increases in the long run is yet to be seen.

Sturgeon have been swimming in the lakes and rivers here for tens of millions of years, and preventing the entire species from dying out forever will ultimately depend on maintaining these conservation efforts for years to come.

I got you, baby.

We're going to put you back!

-You can kind of hold him here for just a second and make sure everything looks good, make sure he's gilling and his tail's kicking.

Yeah, looks really good.

He's gonna go.

As soon as you let him go, he'll take off.

-There you go.

-And that's it.

-Wow!

Thank you!

That was awesome.

What a special thing.

And so we learn one more little piece of information about our world, one that gives us a better grasp on the concept of extinction and what it means to put effort into maintaining the spectacular diversity of life on Earth.

You can look at the impact that humans and that we as individuals are having on our planet, and in the geologic context, it's really easy to be like, "You know what?

We're not here that long.

Nothing I can do can make a difference.

It doesn't matter.

I'm gonna burp all of the carbon emissions I can into the environment, and I'm gonna die, and it's not gonna matter."

I mean, you can take that real nihilistic approach to it.

Or you can be like, "Wow, we aren't here for very long.

Every day matters.

The way that we spend every day of our lives matters.

What we do with our time matters.

Where we focus our energy, it matters," you know?

Because it is a finite resource.

Another thing that's been so incredible is learning how scientists take that sense of responsibility really seriously.

Wow.

You know, that is why they're so focused on what they do.

That is why they are so undeterred in the pursuit of knowledge and discovery... -It'll be a lot of fun to see if there is more.

-...and wanting to share that with the world by, like, inviting our documentary crew to come along to their sites with them.

-I just can't believe that this all happened on the day that you were here.

-I know.

[ Laughs ] That to me has been really emotional, 'cause I'm never going to look at a summer the same way again.

I'm always going to be thinking about the research that's happening out here and, again, just in my day to day, what can I do to live a meaningful and deliberate life?

This Prehistoric Road Trip took us to nearly 40 sites over a 5-state region throughout the course of exploring hundreds of millions of years of Earth's history.

Because of it, I'm in awe of our planet's resilience and feeling a renewed sense of responsibility to care for all that has survived and all that we've inherited.

And I'm curious -- What new discoveries await us in the coming centuries?

What new life forms, recent or extinct, might we uncover?

And as we hurtle into the future, what will be preserved in the new chapters of Earth's history?

Whatever happens, I'm excited to know that journey and its story awaits us still.

-Yeah, we were just walking, and I saw some white stuff, and I was like "Oh, that's probably bones from an animal.

I should go check them out."

And then I picked them up 'cause I have no filter on what I should do.

[ Man speaking indistinctly ] -Whoo-hoo-hoo.

-To order "Prehistoric Road Trip" on DVD, visit Shop PBS or call 1-800-Play PBS.

This program is also available on Amazon Prime Video.