The County Naturally—Re-writing Ice Age Horse History—Pamela Stagg—99.3 County FM

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Ep 1/3: The County Naturally. Rewriting Horse History. Part 1. Pamela Stagg—Dr. Grant Zazula, Yukon Gov. Official Paleontologist—99.3 County FM
Ep 2/3: The County Naturally. Rewriting Horse History. Part 1. Pamela Stagg—Dr. Grant Zazula, and Dr. Alisa Vershinina, paleogeneticist—99.3 County FM
Ep 3/3: The County Naturally—Rewriting Horse History. Part 3. Pamela Stagg—Dr. Ross MacPhee, Curator, American Museum of Natural History, New York—99.3 County FM

Ep 1/3

[Pamela Stagg]
The following is a presentation of CJPE 99.3 county FM.
The voice of the county in Prince Edward County, Ontario, Canada.
Welcome to The County, Naturally. I’m Pamela Stag
Today: Rewriting history
In grade four, Mrs Wilson taught us that the Spaniards brought the first horses to North America. Sorry to contradict you, Mrs Wilson, but you were dead wrong. Horses originated in North America. Those Spanish horses were descendants of the original North American ancestors. An international team of research scientists has been studying the origins and spread of ice age horses. Last summer I had the honor of talking to three of those scientists. Dr Ross MacPhee at the American Museum of Natural History in New York city. Dr Alisa Vershinina, a paleogeneticist in California, and Dr Grant Zazula, a paleontologist in whitehorse. They’ll be joining me over the next three programs to talk about their groundbreaking research. The story begins in Yukon. It turns out that Yukon Alaska and Siberia are key in the study of ice age mammals. In fact, Yukon is such an important player in ice age research that the territory has its own official government paleontologist,Dr Grant Zazula. He’s on the line from Whitehorse. Welcome to the program, Grant

[Zazula] Thank you so much for having me Pamela.

[Pamela Stagg]

Grant, Why is the north so important for studying ice age mammals?

[Zazula] There’s a couple of reasons. Firstly, most of northern Canada is covered by permafrost, frozen ground.

That means that for animals and plants and anything that was living in the past, when they died, often their remains got preserved in frozen ground and then remained deep-frozen for thousands of years.

The bones and ancient remains of these animals and plants that lived during the ice age are so incredibly well preserved in the permafrost. For example, we have a mummified wolf pup that’s over 50,000 years old, that has hair and skin, and eyes.

But it’s also because during the ice age, when most of Canada was covered by massive glaciers several kilometers thick, strangely north and west Yukon remained free of ice. It was cold enough to support glaciers, but it was too dry. So it remained, this ice free landscape, for most of the last couple million years. That ice free landscape of Yukon was also connected with Alaska, which remained ice free.

And because so much of the world’s water was locked in glacier ice that was covering places like the arctic of Canada, the arctic of Scandinavia, sea levels were depressed by over 120 m, exposing this Bering Land Bridge in the present day region of the Bering Strait. Those continents were connected, animals were able to move back and forth between Asia and North America.

But because so much of Canada and most of the north was covered by ice, those animals needed to live somewhere.

Places in the interior of Alaska and Yukon were a refugium for these ice age animals. We call [it] the mammoth steppe – an ecosystem with woolly mammoths and horses and bison and scimitar cats and lions. When they died, their bodies, their bones remained locked in permafrost until people like me come along and find their fossil bones and then make them available for scientific study like this.

[PAMELA STAGG]

Grant.

When I hear the term land bridge, I always think of something like the Golden Gate Bridge. Was the Bering Land Bridge also long and very skinny

[Zazula] Absolutely not.

The term Bering Land bridge is a terrible term.

It was a subcontinent over 1500 kilometers north to south.

Animals were living there and occupying this region, which is really the heartland of the mammoth steppe ecosystem.

[Pamela Stagg]

Horses evolved in North America.

They lived in Beringia,then they started to move into Asia. But migration through Beringia wasn’t just one way. Grant, tell me about animal movement between Alaska and Siberia.

[Zazula] We know that some animal groups evolved in North America like horses. And, in fact, some mammals evolved elsewhere and moved into North America. Bison evolved in Eurasia and then moved to North America.

So there was this exchange of animals constantly through the ice age.

Looking at the DNA from fossil bones of ice age horses in Yukon and then comparing them with those in Siberia and Alaska and Europe, we can show that these horse populations were always there through the ice age, often connected between Asia and North America.

The Bering Land Bridge during the ice age enabled those horses to move from North America into Asia, Europe and eventually Africa and then populate most of the world.

[PAMELA STAGG]

This is The County, Naturally and I’m Pamela Stagg today.

I’m talking to Dr Grant Zazula in Whitehorse.

He’s part of an international team of scientists that is rewriting the history of the ice age horse.

The first people to arrive in North America also came here via Beringia, Grant.

When was that?

[Zazula] The first evidence for people living in the far north and in the arctic of Siberia is about 35,000 years ago.

We soon after see evidence of the first people in North America maybe about 20,000 years ago.

This was the first time North America was populated by people. They were hunting and maybe even scavenging animals like woolly mammoths and horses and bison, [which] would have been a really important food source. Around 20,000 years ago, when these first people are moving into North America, climate starts to warm up and that mammoth steppe grassland that covered most of the northern hemisphere was starting to become occupied by shrubs and trees.

These animals start to die off and we suffer major extinctions in North America of many, many animal groups by about 12,000 years ago.

As far as we know, based on fossil evidence, North American horses were all lost around 12,000 years ago. But it’s also a time of massive environmental change with warming climates at the end of the ice age.

[Pamela Stagg]

Is there any evidence that those people domesticated the primitive horses?

Or was it just a food source for them?

[Zazula] So far, there doesn’t seem to be any good scientific evidence that North American indigenous people were able to domesticate horses like they did in Asia.

There’s evidence of horse hunting in North America at the end of the ice age, evidence for people scavenging horse carcasses. Those earliest people in North America were hunter gatherers and they weren’t really able to domesticate these animals.

Soon after people arrived on this continent, horses were gone, horses may have become extinct in North America, but their bones remain.

[Pamela Stagg]

One of the more important finds was a 60,000 year old horse discovered in Yukon. Grant,how was the horse found?

[Zazula] Yukon is an amazing place to study ancient horses because we have this incredible record of fossil horses preserved in the permafrost.

Most of these fossil bones are found by gold miners outside Dawson city.

Gold mining continues today.

These gold miners – most of them are small scale family operations.

They’re constantly removing the permafrost to get at these gold bearing gravels.

Those gravels also contained an amazing assortment of ice age animal bones.

We have a program – the Yukon Government paleontology program where we go out for most of the summer and interact with these gold miners.

They’re constantly uncovering ice age animal bones in the summer.

We may collect five or six or 7000 individual bones of woolly mammoths and horses and bison and lions, ground sloths, giant beavers. Horses are one of our more common animals that come out of the permafrost.

So yeah, there’s 60,000 year old horses.

Our best preserved, most ancient fossil horses are about 700,000 years old, found in the early 2000s at a site called Thistle Creek beneath a volcanic ash bed. We find the remains of these volcanic eruptions from volcanoes in Alaska and we can use those volcanic ash deposits as dating tools.

If we find a fossil beneath or above these volcanic ash beds, we can have a fairly good idea of how old those bones are.

And one of these horse bones was over 700,000 years old. Remarkably, DNA was preserved in that bone. Until quite recently, that was some of the oldest DNA that had ever been sequenced in the world and that was from a caballine horse at Thistle Creek, Yukon.

These gold mine sites are literally a goldmine for ice age paleontology.

Another really key partner in all our research are the indigenous people.

The First Nations people have a history of collaboration between scientists and First Nations people that goes back a very long time. Back to the gold rush when the first fossils were being discovered in the Yukon because of gold mining. A lot of scientists came to the Yukon to go look for these fossils so they could bring them back to their museums. Of course when these scientists got to the Yukon, they didn’t really know where to go. And, they developed relationships with the local First Nation people who often took them out on the land to go look for fossils.

And that partnership with paleontology and First Nation people, it’s really remarkable.

Most of the field projects that we do now always have First nation people involved because it’s their land.

They are so interested to learn about the history of their land.

We learn a lot from the First Nations people in Yukon and they’re very curious and very interested in being a part of the Western scientific understanding of the land.

It’s always really remarkable to me, when we’re out working with First Nations people and they are walking along and they look, whoa, what is that? Could be a woolly mammoth molar, a tooth that’s over three kg and 30 centimeters long and they look at this and go, wow, that’s a woolly mammoth that lived here in my backyard.

That moment of learning and realization and discovery for First Nations people is remarkable, to be a part of this for people who are living in often remote places in Canada and the world is changing in front of them.

Climate change is doing crazy things in the north.

We have permafrost melting, we have vegetation changing, we have rivers flooding. And fossils give that opportunity to talk about how those changes have been occurring for hundreds or thousands of years, tens of thousands of years, all within that time frame of their people being in North America.

[Pamela Stagg]

You mentioned the term caballine horse.

What is a caballine horse?

[Zazula] A caballine horse is a horse that is either domestic horse or directly related to domestic horses.

We have very different lineages of horses that evolved during the ice age, and that are present today on the landscape.

Caballine horses, but also other groups like stilt legged horses, the asian wild horses, their legs are different. Genomically, they are a different lineage.

We also have zebrine horses like the zebras in Africa today, their ancestors also evolved in North America and they dispersed across the Bering Land Bridge and eventually made their way to Africa. We know that there’s these various different horse groups that evolved in the past and caballine horses are the one lineage that was eventually domesticated.

Those are the most common ancestral horse bones that we find in the Yukon, the direct ancestors of domestic horses today.

[Pamela Stagg]

As your colleague Dr Ross MacPhee once said, you’re looking at history in the rear view mirror

[Zazula] That’s the great thing about this kind of work, we’re trying to reconstruct what events have happened in the past, why they happened. But when you’re looking in the rear view mirror, you never get the complete pictures.

Every new discovery adds to that picture.

You have to be open minded because we developed these hypotheses and theories about things. But often they get overturned by new discoveries.

Part of this horse project has really been a lot of discovery.

Twenty years ago, there was a very, very different understanding of horse evolution in North America during the ice age based on studying bones and measuring bones and describing bones.

DNA has really upended that whole scenario.

Now we know that there was probably only one or two, maybe three different types of horses in North America, not 100 like what people have thought before.

In this case, we’re being able to really build up a new understanding and a new theory of how horses evolved in North America and were connected with those in Asia and Europe.

[Pamela Stagg]

In Minnesota and northwestern Ontario, there’s a breed of pony, the Lac La Croix horse known as the Ojibwe pony.

Some say it was bred by the First Nations.

Others say the Lac La Croix Pony survived the ice age extinctions and lived to the present day,

Grant, is that possible?

[Zazula] I would say it’s a possibility. We generally place their extinction date around 12,000 years ago, but there’s bits of evidence coming out now that seems to suggest they may have survived longer.

Maybe there were some populations that continued in North America through the end of the ice age into modern times?

[Pamela Stagg]

Next: Science fiction becomes reality.

I’m Pamela Stagg and this is The County, Naturally. Dr Grant Zazula, Yukon’s official Paleontologist is on the line today from Whitehorse. He’s part of an international research team that has been studying ice age horses using DNA.

Grant, five or 10 years ago, sourcing the DNA of ancient animals would have sounded like science fiction.

What made this possible today?

[Zazula] 20 years ago we were thinking about all the cool things we could eventually do one day with ancient DNA.

The technologies have evolved so amazingly that most ice age paleontology studies now incorporate ancient DNA, especially those studies that are occurring in the North.

It gives us so many new insights into the evolution of animals.

There’s only so much you can learn by measuring bones, looking at their size, looking at the shape.

We’re learning so much more new information based on ancient DNA and being able to draw clear connections between, for example, living animals like domestic horses and their ancient relatives. Most of the horses that we have here from the Yukon, going back 15,000, 20,000 or 50,000 years old, the genetics show that they are directly related to these groups of horses that were eventually domesticated, the horses that we know of today and love.

Those are the same horses that were living in Yukon 30,000 years ago.

The ancient DNA really provides the best evidence for those relationships.

It enables us to ask questions that we would have never even come close to being able to ask before because the technologies now enable us to ask these really interesting questions about the relationships amongst organisms. Before, those ideas were based on speculation or on very, I would say, scientifically primitive methods.

But now getting out the biomolecules and the DNA and sorting out some of these relationships is just remarkable.

[Pamela Stagg]

And the research team is truly international as well as scientists from Canada and the U. S., there are researchers in France Norway, Sweden, Denmark, Germany, China and Russia.

How can such a widely scattered group work together?

[Zazula] We are constantly having international meetings on zoom.

The geography doesn’t really separate us because of the internet and I think that’s a really remarkable part of the scientific process.

It’s quite new because of technology.

But also there’s a lot of people who are very, very interested in the ice age animals, especially those from the permafrost. Horses are an animal that people really, really love.

And it’s really easy to attract interest in scientific studies involving horses, especially with ancient horses and DNA.

We have a real opportunity here in Yukon because of the wealth of fossils and the great preservation of them, that so many different research groups are interested in working with us.

It’s a real privilege to be able to share what we have with them and invite them to work on these projects.

But also to share what the Yukon has to offer.

Studies of Yukon ice age fossils are becoming a really big deal across the world.

We’re just really thankful that we can help contribute to them.

[Pamela Stagg]

Grant, thanks so much for joining me today.

[Zazula] Thank you so much Pamela.

[PAMELA STAGG]

I’ve been talking to Dr Grant Zazula.

He’s the Yukon Government’s official paleontologist.

He joined me by phone from Whitehorse and that’s the program for today.

I’m [Pamela Stagg].

Thanks for joining me on The County, Naturally.

See you next week.

This has been a presentation of CJPE 99.3 county FM.

The voice of the county in Prince Edward County Ontario Canada.

Ep 2/3

[PAMELA STAGG]

The following is a presentation of CJPE 99.3 county FM.

The voice of the county in Prince Edward County Ontario, Canada.

Welcome to The County Naturally.

I’m Pamela Stagg

Today: Rewriting history, Part two.

An international team of research scientists has been studying the origins and spread of ice age horses.

Last summer I had the honor of talking to three of those scientists.

Dr Ross MacPhee at the American Museum of Natural History in New York City.

Dr Grant Zazula, a paleontologist in Whitehorse.

And Dr Alisa Vershinina, a paleogeneticist in California.

Last week, Dr Grant Zazula told us about the origins of the horse in North America and how those ancient horses were forced into the ice free areas of Yukon and Alaska during the ice age, along with woolly mammoths, scimitar, cats, lions, and camels.

[Zazula] We know that some animal groups evolved in North America, like horses. And in fact [many] mammals evolved in North America. Bison evolved in Eurasia and then moved to North America.

So there was this exchange of animals constantly through the ice age.

We can show that these horse populations were always—through the ice age—often connected between Asia and North America because so much of the world’s water was locked in glaciers during the ice age.

The sea level dropped and a huge subcontinent Beringia, also known as the Bering Land Bridge rose from the ocean. Horses and other ice age mammals moved into Beringia and on to Asia. bBson came the other way, to North America.

 Bcause so many of these ice age animals are preserved in northern permafrost, Yukon has become a center for paleontology.

Yukon is an amazing place to study ancient horses because we have this incredible record of fossil horses preserved in the permafrost.

Most of these fossil bones are found by gold miners. These gold miners and most of them are small scale family operations.

They’re constantly removing the permafrost to get at these gold bearing gravels.

[PAMELA STAGG]

Those gravels also contained an amazing assortment of ice age animal bones.

[Zazula ] Our best preserved, most ancient fossil horses are about 700,000 years old, found in the early 2000s at a site called Thistle Creek. Remarkably, DNA was preserved in that bone.

Until quite recently, that was some of the oldest DNA that had ever been sequenced.

20 years ago, the idea of sequencing a genome that’s that old would simply have been science fiction.

But technology has changed radically.

It enables us to ask questions that we would have never even come close to being able to ask before. Because the technologies now enable us to ask these really interesting questions about the relationships amongst organisms. Before those ideas were based on speculation or on very, I would say, scientifically primitive methods of measuring bones and describing features.

But now getting at the biomolecules and the DNA and sorting out some of these relationships is just remarkable.

[PAMELA STAGG]

And that was Doctor Grant’s Zazula. Joining me now is Alisa Vershinina, a postdoctoral scholar at the paleogenomics lab at the University of California Santa Cruz.

She’s on the line from California.

Welcome to the program Alisa.

 
[Vershinina] Hi Pamela.

Thank you for inviting me!

[PAMELA STAGG]

Alisa,

What exactly is paleogenetics?

 
[Vershinina] Paleogenetics is a science of recovering genetic information from any specimens that are no longer alive. Those specimens are, for example, museum specimens, or fossil specimens.

Anything you can find out in the dirt. If it’s a bone, paleogenetics provides access to DNA from this biological material.

[PAMELA STAGG]

You’ve been looking at horse DNA that 60,000 years old.

How is it possible to sequence DNA which is that old?

 
[Vershinina] It is possible due to an amazing technology that we currently have.

We have special protocols for extracting DNA.

They are extremely, extremely sensitive to fragmented and damaged DNA, because these are characteristics of DNA extracted from old material.

DNA from paleontological material is no longer intact.

The idea behind the method is optimization for very short fragments of DNA, for DNA that is degraded.

Degraded DNA will not look like anything that we extract from, for example, blood or other freshly-preserved biological tissue.

So we have a collection of methods optimized to work with very damaged and degraded molecules.

[PAMELA STAGG]

Next: Going deeper.

This is The County Naturally.

And I’m Pamela Stagg.

 Dr Alisa Vershinina is on the line from the paleogenomics lab of the University of California Santa Cruz.

Alisa, the focus of your work is mitochondrial DNA.

What is that?

 
[Vershinina] Mitochondrial DNA is a molecule located in a cell’s organoid.

We all have a nucleus in a cell and we have mitochondria in a cell.

A cool thing is that there is a lot of mitochondria in a cell, while a nucleus is usually one per cell. Therefore there is a lot of genetic material available from mitochondria.

So what we’re doing is – we take the sample into the lab, we powder the bone (we usually work with bones), then we powder the bone.

We extract the DNA and sequence it on a sequencing machine. Then we find those molecules that belong to mitochondrial DNA.

And there are usually a lot of them because mitochondria are numerous in the cell.

[PAMELA STAGG]

You looked at samples of mitochondrial DNA from the remains of 178 ice age horses located across Eurasia and North America where specifically with these prehistoric horses found. A lot of other samples are from the north.

[Vershinina] Because in the North there is a lot of permafrost. Permafrost is like a freezer for DNA preservation.

We find a lot of samples up there. We are specifically working with samples from Chukotka, Taymyr in Russia, Russian far east, some parts of Asia, and the north American continent.

We have a lot of samples that are coming from Alaska, for example, from Alaska North Slope, and Seward peninsula.

And we also have quite a bit of samples from Yukon, especially the Klondike region.

[PAMELA STAGG]

What did you discover from their DNA?

 
[Vershinina] First of all, we discovered two major lineages of horses that existed 50,000 years ago. One of them belongs to the North American continent, and another one to Eurasian continent.

Actually, those lineages were exchanging genes. This is a brand new finding we just discovered.

It was previously thought that [different horse populations] were quite isolated.

But what we’re seeing is gene flow from North America into Eurasia and back.

And another thing that we found is that North American horses, who originated in North America and dispersed into Eurasia, [they] went back to north America. [That happened] after dispersal into Eurasia and that is also something new and something that hasn’t been found before.

[PAMELA STAGG]

Did this exchange of genes happen because of the Bering land bridge?

[Vershinina] Yes, it did actually happen during the periods when Eurasia and North America were connected through the area of land. That is called the Bering land bridge. There were several periods when the Land Bridge was open. In all of those periods we are finding an evidence that horses were traveling back and forth between the continents.

[PAMELA STAGG]

You also looked at nuclear genomes.

What are those?

 [Vershinina] Those are genomes that are harder to work with than mitochondrial.There is only one nucleus in [each] cell. The amount of DNA in the nucleus is way more than mitochondria, [however] it’s harder to recover.

Nuclear genomes are different from mitochondrial genomes because nuclear genomes are inherited from mom and dad. The mitochondrial genomes are inherited only from your mom. So when we’re looking into the nuclear genomes, we actually can see a [more full] story. [Therefore in this genetic material] we have more information about the past events.

[PAMELA STAGG]

You were able to sequence nuclear genomes from two recently discovered horse remains in Yukon.

What did you discover?

[Vershinina] We were able to recover those genomes with very good quality and we compare them to nuclear horse genomes from Eurasian continent. We found gene exchange between this continent [and Yukon] and we can see pieces of genetic information of North American horses present in genetic information of Eurasian ones and vice versa.

So we saw additional evidence of gene flow between the continents.

But we only could do that [thanks to] those North American horses.

[PAMELA STAGG]

In other words, the nuclear DNA confirmed the information found in mitochondrial genes.

Next: Feral or wild?

I’m Pamela Stagg and this is The County, Naturally. Paleogeneticist Dr Alisa Vershinina is on the phone from Santa Cruz, California.

Alisa, it used to be thought that horses crossed the Bering Land Bridge from North America to Asia and quickly evolved into different breeds.

Did your research confirm as a lot of paleontologists believed that there were multiple species of horses in North America, multiple species of horses in Eurasia?

 
[Vershinina] It has been previously thought that all horse species were quite isolated.

We did not find that to be the case.

We found that there were two major [horse] lineages.

Those lineages were distinct, but they were also connected through the gene flow through the Bering Land Bridge.

[PAMELA STAGG]

How does the ice age horse DNA compare with horse DNA today?

 
[Vershinina] When we compare present day horse DNA with DNA of ice age horses, we find several things.

First of all, we find that [ancient] Asian horses and other Eurasian horses are extremely similar to those [horses] that we have today.

Maybe they’re not looking like [domestic horses] because they were not domesticated at that time.

But genetically they are almost the same.

Another thing that we found is that for the North American lineage and for North American horses, there are actually regions of the genome that look like Eurasian horse. That is due to this gene exchange that we found.

[PAMELA STAGG]

So what I’m hearing is that the ice age horses of North America and Eurasia are the ancestors of all the horses alive today.

Is that correct?

Yes, they are. The ancestral horses from North America migrated through the Bering Land bridge around one million years ago into Eurasia. In Eurasia (much later) they were domesticated.

And there is a lot of research that tells us about this process of domestication.

But we found that, before the domestication process, [the range] of Eurasian horse populations stretched  into North America.

[PAMELA STAGG]

What can we learn about feral horses—that is, mustangs—in North America from the Ice Age study that you’ve been doing? What we do know is that in North America around 11,000 years ago, horses went extinct.

 
[Vershinina] The feral horses that we see in North America today were actually brought on this continent by Europeans. This process [currently] is considered to be an invasion. However, [our research shows] this biological invasion actually can be considered a reintroduction because these horses were here 11,000 years ago. It’s not that much time in an evolutionary time frame. It’s not that much time geologically. What we can learn is that actually the status of the North American [feral] horse can be changed from invasive to something that actually belongs to this continent. They are initially from here and they were here for millennia before going extinct 11,000 years ago. That extinction was likely regional and not global because the population that many of the North American horses belong to was stretched into Eurasia as well. In Eurasia, this population survived.

[PAMELA STAGG]

So we shouldn’t be calling them feral or non-native horses.

We should be calling them wild horses.

 
[Vershinina] Exactly.

[PAMELA STAGG]

And that’s a revolutionary change!

Alisa, Thanks so much for joining me today.

 
[Vershinina] Thank you so much for inviting me.

This is very exciting to speak about the project.

I’ve been talking to Dr Alisa Vershinina, a postdoctoral scholar in the Paleogenomics Lab at the University of California, Santa Cruz. She joined me by phone from Santa Cruz.

I’m Pamela Stagg.

Thanks for joining me on The County, Naturally.

See you next week.

This has been a presentation of CJPE 99.3 county FM.

The voice of the county in Prince Edward County Ontario Canada

Ep 3/3

[PAMELA STAGG]

The following is a presentation of CJPE 99.3 County FM.

The voice of the county in Prince Edward County, Ontario, Canada.

Welcome to The county, Naturally.

I’m Pamela Stagg.

Today: rewriting history, part three.

An international team of scientists has been studying the origins and spread of ice age horses.

Last summer I had the honor of speaking to three of those researchers.

Dr Ross MacPhee, at the American Museum of Natural History in New York City.

Dr Grant Zazula, a paleontologist in Yukon, and Dr Alisa Vershinina, a paleogeneticist in California.

Two weeks ago, Dr Grant Zazula told us about the origins of the horse in North America and how those ancient horses were forced into the ice-free areas of Yukon and Alaska during the ice age–along with woolly mammoths, scimitar cats, lions, and camels,

Because so much of the world’s water was locked in glaciers during the ice age, the sea level dropped and a huge subcontinent, Beringia, also known as the Bering Land Bridge, rose from the ocean, and horses and other ice age mammals moved into Beringia and on to Asia.

[Zazula] We know that some animal groups evolved in North America, like horses. Camels evolved in North America. Bison evolved in Eurasia and then moved to North America.

So there was this exchange of animals constantly through the ice age.

These horse populations were always–through the ice age–often connected between Asia and North America .

Because so many of these ice age animals are preserved in northern permafrost, Yukon has become a center for paleontology

[Zazula] Our best preserved, most ancient fossil horses are about 700,000 years old. Remarkably, DNA was preserved in that bone.

Twenty years ago, the idea of sequencing a genome that’s that old would simply have been science fiction.

But technology has changed.

Here’s Dr Alisa Vershinina, a postdoctoral scholar at the Paleogenomics Lab at the University of California, Santa Cruz.

She spoke to us last week.

[Vershinina] We have special protocols for extracting DNA.

They are extremely sensitive to fragmented and damaged DNA. Because they need DNA from material that is that old, it’s not going to be intact.

Alisa compared the DNA from ice age horse bones that came from Yukon, Alaska and Russia.

[Vershinina] We find that for Eurasian populations and for Eurasian lineages, ice age horses are extremely similar to those that we have today.

For the North American lineage, there are actually regions of the genome that look like Eurasian horse.

So what I’m hearing is that the ice age horses of North America and Eurasia are the ancestors of all the horses alive today.

[Vershinina] Yeah, they are the ancestors. In North America around 11,000 years ago, horses went extinct.

The feral horses that we see in North America today were actually brought on this continent by Europeans.

This study shows that this process that is considered to be an invasion–biological invasion– actually can be considered a reintroduction, because these horses were here 11,000 years ago.

It’s not that much time in evolutionary time.  Not that much time geologically.

What we can learn is that actually the status of the North American horse can be changed from invasive to something that actually belongs to this continent.

And that brings me to today’s guest, Dr Ross MacPhee. He’s the senior curator, Department of Mammalogy, Division of Vertebrate Zoology at the American Museum of Natural History in New York City.

He’s on the line from New York.

Welcome to the program, Ross.

[MacPhee] Thank you very much Pamela. It’s a pleasure to speak with you.

Ross, now that the research team has proved that today’s mustangs are descended from the original prehistoric horses of North America, is it time to reclassify them from invasive aliens to a native species?

[MacPhee] I would like to see horses regarded as a native species.

The caballine horses are the ones to concentrate on, because those are the ones that gave rise to horses as we know them today.

They lived all the way from Herschel Island north of mainland Yukon down into Patagonia, and they prospered until about 11,000 years ago, when sadly all of them disappeared.

Caballine horses originated in North America.

That fact should be respected by declaring them part of the native fauna, despite the fact that they disappeared for a while.

They were reintroduced 500 years ago and that should not have any appreciable scientific effect on whether we regard them as native.

Ross, two weeks ago, Dr Grant Zazula talked about the Lac La Croix pony, also known as the Ojibwe pony, that’s found in northwestern Ontario and northern Minnesota.

Some people say that the pony escaped the ice age extinction and lived undetected to modern times.

[MacPhee] This is the most fascinating new science that’s going on right at this minute.

All the big mammals, the mammoth, the ground sloths, the sabertooth cats, and on and on, disappeared fairly suddenly about 11,000 years ago.

But there’s always been stories, particularly indigenous North American stories that horses survived.

We don’t have evidence of that yet.

But what we do have evidence of is that horses, caballine horses—again, horses that are in the same group as domestic horses that we recognize today—survived in Yukon up until about 6000 years ago.

If we had evidence that came from later periods, we’d probably be able to fill in that gap between 6000 and the arrival of Europeans.

We don’t have that, so scientifically, I can’t say that there was survival right up to modern times, but at least it’s a possibility now.

Now, scientifically does that change things?

Well, of course, it changes things, from the point of view of whether horses should be considered part of the native fauna of North America.

If they survived, even in small numbers, then there is no reason left to consider them a different species.

Whether or not this is the case is going to depend on sampling them, and I’m anxious to see that it happens.

If we can show that there are survivors, then there is no basis for considering horses of the domestic kind different from wild horses or the horses of the Pleistocene.

Next: Why this matters today.

This is The County Naturally, and I’m Pamela Stagg.

On the line I have Dr Ross MacPhee of the American Museum of Natural History in New York City.

Ross, horses were here until 11,000 years ago.

It has to have implications for the way we view grassland ecology in North America

[MacPhee] Most of central Canada is still in grassland. There are very few large mammals that are adapted to it.

You only have to turn the clock back about 11,000 years or a bit more, and the range of large mammals that existed on the grasslands of central North America was quite considerable.

There were of course horses, but there were others, and these large mammals were very important for keeping the grasslands productive.

What they contributed was not only their manure, but also turning over the soil.

One other species that I forgot to mention—very important–were mammoths. We think of mammoths as being largely confined to very cold regions, say Northwest Territories, Alaska, and Siberia, but mammoths lived all the way down to the valley of Mexico.

They were grass eaters, making sure that it continued to be a very productive environment.

Mammoth Steppe, an alternative word for prairie, existed all the way from central Siberia over to at least as far as Yukon and probably a little bit into Northwest Territories.

This was one of the most productive landscapes on the planet at the time.

It was a dynamic kind of productivity.

It was because you had so many large mammals, surely in the millions, making the soils as rich as possible, and making it possible for many other kinds of species to have a good life as well: smaller mammals, birds all the way down to microbes, which are also terribly important for the maintenance of ecosystems.

Species like bison have largely disappeared from the grassland of the Canadian West.

Today bison from Elk Island National Park are being airlifted into the back country of Banff National Park.

Ross, if we consider this to be a reintroduction of the bison, shouldn’t we look at horses the same way?

[MacPhee] Well, of course we should, and to a degree it’s happened naturally—there are wild horses from southern Alberta.

The contrast is what we think of bison and what we think of horses.

We feel very guilty about bison, both in the U. S. and in Canada.

There were tremendous hunts designed to bring them down to very small numbers that had something to do with the suppression of native peoples.

But it also had to do with the idea that these [animals] were taking up room that could be turned into agricultural plots and that’s exactly what happened.

Areas that were formerly pristine grassland, of a kind that had existed in North America for many millions of years, were turned into monoculture agriculture.

There’s nothing else over vast, vast areas; all there is…is agriculture.

Species that ordinarily would have been present aren’t there.

There aren’t big mammals other than the ones that are encouraged to be there now.

Pamela, you mentioned in Banff that there’s an interest in repopulating with bison.

Well, that’s great, because bison certainly lived right up to the mountains back in the Pleistocene.

We have fossils that prove that.

But what about the horses?

The horses are part of the natural landscape of northern North America.

They should be there because they’re one of the very few remaining megabeasts that still live in North America.

Next: wild horses and the law.

I’m Pamela Stagg and this is The County Naturally.

Dr Ross MacPhee is on the line from the American Museum of Natural History in New York City.

Ross, you were asked to address a conference on wild horses and the law.

[MacPhee] This was a symposium at the New York University School of Law.

The title of it was “Managing to Extinction”.

And what it was focused on was how the American federal government, the Bureau of Land Management, controls wild horses in the western part of the country.

They’re limited by law to places in which the Bureau of Land Management conducts its business.

That’s not to say you can’t have private herds, but I’m ignoring that for the moment.

Horses that are on the landscape are in Herd Management Areas, as they’re called, and it’s in these areas that the horses are supposedly protected and live out their lives.

But that isn’t what really happens: what really happens is encroachment, because there are millions of privately held cattle that are on public lands.

The license fee for putting them there to graze is a trivial amount.

What this has ended up being is a conflict between those who are raising livestock for commercial purposes—cows—versus a species that should be protected as a native species in North America, but is seen as an invasive species by definition in the rule book of the Bureau of Land Management.

The Bureau of Land Management years ago defined horses as an introduced species, as an alien. And that makes a great deal of difference, because alien species are not considered to be part of the native flora and fauna.

So they have no rights, there’s no protections, any more than there are protections for interlopers that we’ve heard about more recently. Murder hornets! Nobody wants murder hornets in their backyards; horses are in that category.

This symposium was to try to answer the question, are we managing horses in a way that’s going to result in their continuance in North America, or are we intentionally managing them to extinction.

10 years ago when I was at this conference, climate change of course was on everybody’s lips, but our experience of it had been very much less

This year, people all over North America are experiencing what the reality is going to be like in future: unbelievably hot during a part of the year, precipitation patterns changing.  

For horses who have largely been confined to herd management areas in the southwestern part of the US, they’re going to be dealing with intolerable temperatures and lack of precipitation.

There is no plan to deal with what climate change is going to mean for horses in places like Nevada and Utah and Arizona.

Where I am now in my own career is wanting this to be my number one priority, to make it possible for horses to have an existence in North America.

Include Canada here: if there is a future for horses and part of that probably will be in Canada, especially in places like central BC, maybe in southern Alberta, I don’t know.

There are so many conflicts in this country regarding whether or not wild horses deserve a place at the table. Just as Canada has embraced surviving populations of buffalo, they should embrace horses.

Ross, in the U. S. activist groups are fighting the Bureau of Land Management to protect wild horses. advocacy groups for the Prior Mountain wild horses come to mind. Do you see more legal action ahead?

[MacPhee] What I foresee is a lot more legal action against the procedures of the Bureau of Land Management, but there’s a problem. Advocacy groups like Prior Mountain have a stone wall of bureaucracy that is extremely hard to overcome.

Everything is completely controlled by the Bureau of Land Management as to whether there’s excess horses anywhere, how they’re going to be dealt with.

There’s no point of view here as to where horses ought to be kept in future if their numbers are going to survive, let alone thrive.

When you get into legal issues, legal definitions really matter.

Let’s go back to the first point we discussed, is it time to change the status of wild horses from feral to a native species?

[MacPhee] I would like to see horses regarded as a native species.

I’m a vertebrate paleontologist and I work all the time in identifying species.

I would bet anything that if you could bring back a Pleistocene horse, say a stallion, and meet that stallion with a mare from today, they would produce viable, fertile offspring.

That’s the very definition of a biological species.

For me, horses are the same thing, whether Pleistocene or modern day. Paleogenetics shows us the horses that lived here 11,000 years ago were insignificantly different from the horses that we have today.

They should all be considered the same thing and treated accordingly.

Ross, you’re obviously passionate about saving wild horses.

[MacPhee] Long before there was steam engines, long before there was any kind of mechanical apparatus to make our lives easier, what everyone depended on was horses.

Horses were regarded as extremely valuable property.

Now, their economic role has been completely supplanted. I’m not saying we need to go back to 1910. What I’m talking about is to respect horses for what they did for us.

In places where it is possible to have herds of wild horses, with minimum human management, we should insist that that happens.

We owe them because they made us what we are.

Ross, thanks so much for joining me today.

[MacPhee] Thank you, Pamela!

I’ve been talking to Dr Ross MacPhee, senior curator, Department of Mammalogy, Division of Vertebrate Zoology at the American Museum of Natural History in New York City.

He’s also the scientific advisor to the Cana Foundation, an advocacy group for wild horses.

He joined me by phone from New York.

And that’s the program for today.

I’m Pamela Stagg.

Thanks for joining me on The County, Naturally.

See you next time.

This has been a presentation of CJPE 99.3 County FM.

The voice of the county in Prince Edward County Ontario Canada

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