Original subtitles

Narrator: In China, archeologists unearth

a grisly site.

Dr. Leonard: In one of the pit houses

that is only 210 square feet,

they find what must be close to

100 human skeletal remains.

Narrator: A team of divers makes a surprising discovery

at the bottom of the Baltic Sea.

Dr. Cantor: It's a shipwreck, lying on the seabed

on an even keel, about 275 feet below sea level.

And somehow it's perfectly preserved, like a time capsule.

Dr. Leonard: Right away, the divers identify it

as at least three centuries old, possibly older.

So what ship is this, and what was it used for?

Narrator: Biologists conducting glacier surveys

in the Andes Mountains find something strange.

Dr. Riskin: There's this tiny, primitive looking,

wingless creature, about half an inch long,

swimming around in a pool of melted water.

And it's not alone. There are dozens of them.

So, what are they?

♪ [show theme music]

Narator: These are the strangest mysteries,

trapped in the coldest places.

♪♪

Lost relics.

♪♪

Forgotten treasures.

♪♪

Dark secrets.

♪♪

Locked in their icy tombs for ages.

♪♪

But now, as ice melts around the world,

♪♪

their stories will finally be exposed.

♪♪

♪♪

Narrator: The Kezuozhongqi Banner is a region located

within the Tong Liao City, in Inner Mongolia, China.

Known for its flat, plain grassland

and growing urban development,

the area has been a hub of activity for thousands of years.

Dr. Cantor: The region has a four-season steppe climate,

which means that it has long, cold, dry winters,

where the temperature drops as low as -14° Fahrenheit

and still receives heavy snowfall every winter.

Dr. Riskin: One day this local farmer is herding his sheep,

and he comes across some random pottery fragments on the ground.

So he digs around, he looks a little deeper,

and then pretty soon he finds a complete jar,

that to him, looks like it might be ancient.

So right away, he reports what he discovered.

Narrator: Archeologists are summoned and discover

a huge ancient site, covering over 100,000 square feet,

with the foundations of several pit houses,

semi-subterranean homes, built by digging into the ground,

to create a sunken living space.

What's inside, leaves them stunned.

Dr. Leonard: In one of the pit houses,

that is only 210 square feet,

they find what must be close to

100 human skeletal remains.

Bones on top of bones.

This is a mass grave.

It's not something that you see every day.

Seven more of the pit houses also have skeletal remains

in them, and they appear to have been

abandoned quickly for some reason.

There are a lot of daily-use tools that were left behind,

suggesting the occupants only left with

their most prized possessions.

So what exactly happened to these people?

And how did so many of them end up dead and left like this?

Narrator: Carbon dating and artifact typology determined

that the site dates back to the Neolithic period,

approximately 5,000 years ago,

around 3000 BCE.

Dr. Agbedor: This was a time before writing was used

in the area, and early agricultural societies

were just starting to flourish.

During this period, people lived in relatively small settlements,

engaged in crop cultivation, and hunted for food.

Dr. Riskin: The site, which has now been given the name

Hamin Mangha, is surrounded by ditches.

It encompasses 54 pit houses,

and more than 1,800 artifacts have been found there.

Things like pottery, tools made of stone,

tools made of bone, tools made of shells,

and all these different objects made from jade,

including ornaments and figurines.

Dr. Agbedor: The amount of bodies is overwhelming,

to say the least.

The initial thought for something this massive

is that it must have been a conflict of some sort,

either among the inhabitants

or an outside group might have attacked them.

Narrator: Only 260 miles away from Hamin Mangha,

another settlement came to a grisly end,

and might have some startling similarities.

Dr. Leonard: In the settlement of Honghe China,

researchers found an abundance of bodies

with their severed skulls,

making it the largest known headhunting site

from Neolithic Asia.

The remains were from 4,100 years ago,

and the evidence points to a compelling story.

Dr. Riskin: Headhunting, as the name would imply,

is the practice of hunting the heads of

the people you've killed.

Basically just taking their head as a trophy.

Now, in some ancient cultures, the head of an enemy

is highly valued for its ritual significance,

because it symbolizes the conquest,

it symbolizes the capture of the enemy's soul,

and it symbolizes the capture of their energy.

In China, there have been lots of head-only burial sites found

in various places all over the country.

Dr. Cantor: A total of 68 skeletons were unearthed

in Honghe, 41 of which were headless.

32 of them seem to have been killed in a single incident.

Four other skulls were also found in a pit

outside one of the houses.

Narrator: After further study of the remains,

the researchers discover something unsettling.

Dr. Leonard: Most of the victims appear to be

females and children.

It's not clear why women and children were targeted

instead of adult men, but it could be

that they were in active conflict with other tribes

and the settlement and might have been attacked

while the men were away.

Dr. Agbedor: Many of the cuts were made

with the same technique each time,

suggesting a consistent method

and weaponry used by the perpetrators.

The weapons were likely bone-handled knives,

with sharp bone blades.

After the attacks, the males probably came home

to this massacre, moved the corpses into two houses

for a simple burial, and left the settlement forever.

So could something similar have happened at Hamin Mangha?

Dr. Riskin: It's unlikely. If the Hamin Mangha settlement

was attacked this way, you would expect to find

weapons all over the place, and there are no weapon artifacts

found at that site at all.

Also, only a few of the bodies seem to have

their head removed from the rest of it,

and there are no marks or trauma wounds on any of the bones.

So, really it has to be something else.

Narrator: As the excavation at Hamin Mangha continues,

they count a staggering

97 bodies in the one room.

The remains are scattered throughout the small structure

and include juveniles, young adults and middle aged adults,

with about half of the victims aged between 19 and 35 years.

Dr. Riskin: Maybe it was a ritual sacrifice.

That's something that was practiced at one point

or another, pretty much all over the world, including China.

In fact, one of the most famous places

where ritual sacrifice has happened was in China.

It's a place called Mogou Village.

It was a group of people called the Qijia,

and when archeologists found that site,

they excavated almost 1,700 tombs,

and many of those showed evidence of human sacrifice.

Dr. Leonard: Within the tombs, there were goods like pottery,

weapons, necklaces and other items.

And entire families were buried together.

Some of the victims of the sacrifices

were as young as 13 years old.

Dr. Cantor: It's not known for certain why the Qijia

practiced human sacrifice

and how they made their selections for this ritual.

They may have enslaved and sacrificed individuals

from conquered groups.

Dr. Agbedor: The Qijia people resided in modest settlements,

featuring small square or rectangular houses,

that were often partially buried underground.

A similar design to the Hamin Mangha settlement.

Narrator: As much as there are some similarities

between the Hamin Mangha site

and the mass tomb of the Qijia people,

there are many differences too.

Dr. Agbedor: The Qijia people use small tombs

that typically contain 4 or 5 sacrificial skeletons.

This practice is a crucial aspect

of their ritual of human sacrifice.

The victims are buried in the tomb passages

within chamber tombs, either buried directly or layered.

In some cases, the victim's hands and feet are bound,

and they died under unusual conditions.

All of these elements contribute to the sacrificial ritual.

Dr. Cantor: Another aspect of ritual sacrifice

is that it usually focuses on one gender or age group,

which the Hamin Mangha site doesn't.

So far, it seems that there are 19 males and 27 females

whose ages span all the way from 3 to 55.

Narrator: As the team at the Hamin Mangha settlement

continue to search through the 97 skeletons,

they notice something that might change everything.

Dr. Leonard: There are traces of fire on some of the 97 bodies.

For what reason, we don't know.

And many of the other pit hoses also had traces of soot,

making it seem like these fires were set,

before they were abandoned.

Dr. Riskin: Inside the house where the 97 bones were found,

there's this dark layer of sediment above the remains,

which suggests that the burning took place

after the bodies were brought into the house.

Also, the ash is only found in the top layer of the skeletons,

meaning that their death was almost certainly

not caused by the fire.

Dr. Cantor: The multiple layers of corpses

and the lack of personal items in the pit house,

suggest that the house was most likely cleaned out

before the bodies were brought there,

and that they were transferred there on purpose,

and piled up by members of the community.

Dr. Leonard: This all could be because of a rampant disease

going through the site,

leading the survivors to do whatever it took

to clear the bodies and save other members

of the community from getting sick.

There are plenty of examples throughout history of plagues

that wiped out entire populations.

Narrator: The Miaozigou Settlement just south

of the Miaozigou Village in Inner Mongolia dates back

to approximately 5,400 to 5,000 years ago,

and features 52 houses.

Dr. Agbedor: When archeologists discovered the site,

they were shocked to find

78 human skeletons

in the abandoned camp.

The bodies found were of all different ages and sexes,

buried in all different areas of the houses.

Fire wasn't used like in the Hamin Mangha site,

but the hypothesis is that a plague,

or something similar happened here.

Narrator: While sickness can come from many different places,

the Miaozigou site has evidence

that the disease might have come

from a very specific source.

Dr. Riskin: Rats. Several rat holes are found

all throughout the structures,

with some of the bones even being dragged into those holes.

And that's led a lot of people to think that those rats

might have brought the plague with them.

Dr. Cantor: The abandonment of the Miaozigou site

happened very quickly.

They left their tools and utensils behind,

and there's no evidence of a flood or fire.

So it's most likely that they left,

because of their fear of sickness.

Dr. Leonard: Whereas the residents of Hamin Mangha

set the place ablaze before they left,

the abandoned bodies and period would suggest

that both sites were possibly fighting the same fight

and might have even been connected,

as perhaps an epidemic was taking over the entire region.

Narrator: Though we do not know for sure

what happened to the Hamin Mangha site 5,000 years ago,

the information we do have would suggest

that they were facing an extinction level event

and just trying to survive to see another day.

♪♪

♪♪

Narrator: Covering an area of nearly 12,000 square miles,

the Gulf of Finland stretches across the easternmost arm

of the cold Baltic Sea.

Dr. Cantor: The Gulf extends for 250 miles east to west,

but it's only 12 to 80 miles across north south.

It's bordered by Finland in the north,

and Russia and Estonia make up the southern shores.

Dr. Leonard: The region has a continental climate

of short summers and long, extremely harsh winters.

The entire Gulf freezes over from December to April,

when the average winter temperature is 14° Fahrenheit.

Strong, western winds frequently cause floods and water surges.

Anthea Nardi: Historically, the Gulf has always been

an important shipping route for its main ports,

like Helsinki in Finland,

St Petersburg in Russia,

and Tallinn in Estonia.

As a result of all that boat traffic,

the sea bottom is home to thousands of shipwrecks,

from every era of international trade.

Narrator: At the mouth of the Gulf of Finland,

a team of international divers looking for relics

of sea battles from both World Wars,

makes a surprising discovery

Dr. Cantor: It's a shipwreck lying on the seabed

on an even keel, about 275 feet below sea level.

And somehow it's perfectly preserved, like a time capsule.

There's none of the damage and deterioration

that you usually find with older shipwrecks.

Most ancient discoveries are worn down over time,

and bio-degraded by bacteria and worms,

until they're barely recognizable debris.

Dr. Leonard: Most of the hull planks are still firmly

in place, and you can immediately tell from the design

that it's clearly much older than a 20th century battleship.

Right away, the divers identify it as

at least three centuries old, possibly older.

So what ship is this, and what was it used for?

Anthea Nardi: Maybe it's an old warship?

The Baltic saw its fair share of naval battles over the years,

and many wrecks have been found on the sea floor.

Narrator: In 2011, the Swedish warship Mars was discovered

at the bottom of the Baltic Sea.

The ship was one of northern Europe's largest

and most feared naval vessels,

used in the northern Seven Years War

between Sweden and a coalition of Denmark, Norway,

Poland and Lithuania.

Dr. Leonard: The Mars was sunk in the first Battle of Oland

in 1564, after an attack from Danish and Lubeckian war ships

sparked a gunpowder explosion at the front of the ship.

Up to 1,000 soldiers were on board

the massive boat when it blew up.

That's roughly the population of an entire Swedish town.

James Ellis: The Mars was discovered roughly

230 feet below sea level.

So professional divers and remotely operated vehicles

had to be sent down to explore the remains.

But it was worth the trouble.

Researchers found cannons, hand grenades,

a large grappling hook and even silver treasure,

most of which was intact.

Narrator: Another Swedish warship,

the 17th century vessel Vasa,

was also discovered at the bottom of the Baltic Sea.

Its remains allowed researchers to fill important gaps,

from what little they knew about the fated ship.

Dr. Cantor: The Vasa was built during the 30 Years War.

[booming canon fire]

The Swedish King, Gustavus Adolphus,

realized that he needed a stronger naval presence,

if he wanted to maintain his power.

So he ordered the construction of five heavy duty warships,

including the Vasa.

Dr. Leonard: The Vasa was impressive

and had awesome firepower.

It was over 225 feet long.

It had two gun decks,

64 bronze cannons

and a crew of 450 men.

Each side of the ship was capable of hurling

550 pounds of shot.

That's twice as much as most European warships from the day.

James Ellis: Unfortunately, the Vasa sunk

during its maiden voyage in 1628,

just 400 feet from land,

in front of a crowd of thousands.

A huge gust of wind billowed the sail,

pulling the ship down until water started to spill

into its open gun ports.

It then toppled over and sank,

killing 30 of its crew.

Anthea Nardi: One thing these two wrecks have in common

is the presence of weaponry,

which you would generally find around sunken warships,

but nothing of the sort was present at the wreck

discovered at the mouth of the Gulf of Finland.

There were no guns at all, not even for self-defense.

So it's highly unlikely that we're looking at

the remains of a naval vessel.

So it must have been used for something else.

Narrator: Members of the dive team explore the wreck further

and make a surprising discovery.

Dr. Cantor: The hold is still carrying a load of grain.

So this must have been a cargo ship.

It also has three masts, and a massive hull design,

which would have allowed for a large shipping capacity.

Dr. Leonard: The ship also has a unique and sophisticated

rigging system that relies on pulleys and tackles,

to hoist and control the sails.

Usually it takes several small teams of sailors

to control sails on a three-masted ship.

But the pulley system on this vessel would have required

a much smaller crew.

James Ellis: Another novel feature is that

all the living quarters are behind the main mast,

below the stern of the ship.

So the entire crew, from the ship's captain to its mates,

cooks and bosun, all lived in the same space,

and ate from the same table.

This is highly unusual for any maritime social structure,

which has always been strictly hierarchical.

Narrator: Based on their initial exploration of the shipwreck,

the team theorizes it is likely a Dutch cargo vessel

called a Fluit.

Anthea Nardi: This is incredible.

Very few Fluits survive today, even as shipwrecks.

So if this ship is in fact a Fluit,

the discovery represents a great opportunity to learn more

about them and add to what we already know.

Dr. Cantor: The Fluit is a bulk cargo ship,

first developed in Holland

and later adopted in other parts of Europe,

including Britain.

but they were particularly dominant in the Baltic Sea trade

between the late 16th and early 18th centuries.

Dr. Leonard: All of the ship's design elements

were in the service of one thing, maximum profits.

So the unique rigging system of pulleys,

allowed for smaller crews, who all have to get paid.

Its large hold capacity means it was heavy and slow moving,

but the amount of cargo it could carry offset the cost

of longer, slow trips.

Narrator: One well-known example of the Fluit,

is the ship English explorer Henry Hudson sailed

on his last voyage to North America, called Discovery.

Backed by private English investors

that included the Prince of Wales,

Hudson set sail from London on April 17th, 1610

at the wheel of the 65 foot long, 55 ton vessel.

James Ellis: It was on the discovery that Hudson reached

what is now the Hudson Strait and Hudson Bay,

in search of the Northwest Passage to Asia,

which of course, he never found.

Anthea Nardi: The Discovery had a crew of 23 sailors,

including Hudson's son, John.

But eventually, there was a mutiny,

and the explorer was cast adrift on a smaller boat,

and he was never seen again.

Dr. Cantor: The fact that the Discovery survived

such harsh conditions,

including a trip around Greenland and Iceland

and getting trapped in the ice in James Bay,

is a testament to the Fluits durability

and resilience in freezing temperatures.

Narrator: Once the divers verify that their find

is a Dutch Fluit,

members of the team spend the next several months

attempting to learn as much as possible about the ship.

James Ellis: They take full measurements of the wreck

and film enough footage to create a detailed 3D model.

In total, they make 15 dives,

clocking in over 2,000 minutes of dive time,

and they're taken aback

by the remarkable condition of the wreck.

Dr. Cantor: The preservation is due to the icy dark waters,

at the bottom of the Baltic Sea itself.

The flow of saltwater into the Baltic is minimal,

mostly due to the lack of connection

with other seas and oceans.

On top of that, fresh water is constantly flowing in

from rivers and rainfall.

All of that results in an unusually stratified sea.

Leonard: The cold, salty water is heavier than fresh water,

so the warm water remains on the surface,

and the deep waters stay frigid. They don't mix.

And this stratification is permanent

at the Baltic's deepest points,

where the shipwrecks are typically discovered.

James Ellis: Bottom of the Baltic is not only cold,

it's extremely dark and has low oxygen levels.

As a result, you won't find the microorganisms that typically

eat away at organic matter, like wood boring worms,

because the conditions are not sustainable for them.

But despite the good condition of our wreck

because of these factors, we still don't know

what ship it is, and when it sank.

Narrator: A full year after the initial finding,

the team succeeds in turning over the ship's transom,

the flat wooden surface facing out of the stern.

It had been lying face down in the seabed.

And when they flip it over, they discover a remarkable image.

Anthea Nardi: There's a wooden engraving of a swan,

and the year 1636.

It's like hitting the jackpot!

In a single moment, the ship's age is revealed to them,

as well as its name, The Swan.

Talk about a great day at the office!

Dr. Cantor: Not much is known about The Swan.

And the team continues to explore the wreck,

alongside Finnish and Dutch authorities.

There's still a great deal of mystery about the ship.

First and foremost, how did she sink?

Dr. Leonard: It's tough to say at this point.

It could have been a freak storm or a rogue wave.

Who knows?

The Baltic Sea doesn't divulge its secrets easily.

Narrator: The discovery of The Swan is further proof

that the frigid waters of the Baltic Sea

contain multitudes and mysteries,

perfectly preserved snapshots of time,

waiting to be explored.

♪♪

Narrator: Located in the vast southern Andes Mountain range

in Patagonia, sits the Patagonian Icefield,

a region that experiences some of the harshest

and most volatile weather conditions in the world.

Anthea Nardi: The weather of the Patagonian icefields

is characterized by strong winds, substantial snowfall

and severely cold temperatures that all contribute

to the glaciers and ice fields in the region.

This makes it an extremely challenging environment.

Dr. Leonard: From steep mountain peaks to flat ice sheets.

The landscape of the region is one of contrasts.

The barren land is filled with ice and rock,

blending with lush vegetation, creating one of the most

visually and ecologically diverse environments

that almost feels otherworldly.

Dr. Riskin: Sadly, rising temperatures from climate change

are having a big effect on the Patagonian ice fields.

They're stunting the accumulation of new snow.

They're melting the ice at this really alarming rate.

It's pretty tragic overall.

But, there is a silver lining.

All of that melting is exposing all of these hidden areas,

that scientists can now go in and study.

Narrator: On one such expedition,

a team of biologists are shocked

when conducting glacial surveys

and discover something strange.

Dr. Riskin: There's this tiny, primitive looking,

wingless creature about half an inch long,

swimming around in a pool of melted water.

And it's not alone. There are dozens of them.

So, what are they?

Dr. Leonard: The body is elongated and slender,

made up of three segments,

the head, the thorax, and the abdomen.

It has two large antenna, six legs.

and at the end of the abdomen, they have

two long and hefty cecri.

Typically they're covered in a silky satea,

which is almost like tiny hairs that help the creature

propel itself through water.

James Ellis: They're mostly found on the actual ice or

inside ice caves or some ponds.

Trying to avoid the sunlight,

they are mostly nocturnal and will slowly migrate

to deeper and darker areas if any light hits them.

Narrator: The southern Patagonia ice field

is filled with fresh water,

but it's not the most hospitable place in the world.

So the researchers are baffled as to how these insects

are not only surviving,

but thriving on this glacier.

James Ellis: To survive in an environment like this,

these creatures would have to be what's called

an extremophile organism,

which are animals that flourish in environmental conditions

that would be hostile or even lethal,

to most other forms of life.

Dr. Leonard: Conditions these organisms can survive,

include extreme hot or cold temperatures,

severe PH levels and even radiation.

They've evolved special adaptations or mutations

that allow them to survive in harsh environments.

As the research continues,

the biologists find that the creatures have

high concentrations of glycerol in their blood,

which is kind of like an antifreeze and prevents ice

from forming within their bodily fluids.

Dr. Riskin: It could be similar to a different insect called

Belgica Antarctica, the Antarctic midge.

Those things live in the Antarctic Peninsula,

which is one of the coldest,

most inhospitable environments on earth,

very similar to the ice fields of Patagonia.

Anthea Nardi: The Antarctic Midge survives cold temperatures

by dehydrating itself,

discharging 70% of its inner water,

and instead producing antifreeze proteins,

that prevent ice formation within its bodily fluids.

They can actually regulate where and how ice forms

in their bodies, minimizing damage to their critical organs.

They're the only organism that lives year round in Antarctica

and requires subfreezing conditions to survive.

But unlike the creatures in Patagonia,

the midges don't live in glaciers.

They live in ice-free patches of soil, mosses and earth,

which is much more hospitable than an ice cold glacier.

Narrator: As the biologists continue their study of these

newly discovered Patagonian creatures,

they realize they can survive another extreme.

James Ellis: When preserving the insect specimens for study,

three of them were boiled in water,

which is a common practice that helps

maintain shape without any damage.

However, after about 15 seconds,

one of the insects crawled out of the boiling water.

Dr. Riskin: Seeing a creature go from freezing temperatures

to boiling hot water and surviving...

that is not something you see every day!

The only other creature I can think of that could do

something like that, is a tardigrade.

Narrator: Tardigrades, also known as water bears,

are microscopic water-dwelling animals,

that can survive extreme conditions

by entering a 'tun' state, where their bodies dry out,

and their metabolism slows to as low as

0.01% of its usual rate.

Dr. Leonard: In its tun state, the Tardigrade can tolerate

temperatures as low as -328°F

and even survive radiation, boiling liquids

and the extreme pressure of the deepest part of the ocean

or in the cold vacuum of space.

And then, when conditions improve,

they can revive themselves.

Dr. Riskin: Tardigrades are way too small to have

specialized organs for circulation or respiration.

They basically just have fluid in the body that bathes

everything with oxygen and nutrients, and it works!

They can be found in the highest mountain environments,

or they could be found at the bottom of the ocean.

Dr. Leonard: What's really interesting is that Tardigrades

can reproduce both sexually and asexually. They can lay eggs,

that can also withstand extreme conditions.

And if they asexually reproduce,

they develop eggs without fertilization.

Anthea Nardi: But while the tardigrade is an invertebrate,

which means an animal without a backbone,

the creature found in Patagonia appears to belong to

the insect family, with a complex body structure.

So the two have different biological makeups.

Narrator: Though these two creatures do share

the uncanny ability to survive extreme temperatures

at both ends of the spectrum,

not much else seems to link them together.

However, there might be another insect that

the Ice Field discovery shares many traits with.

James Ellis: The western Glacier Stone Fly is found

in the Pacific northwest of North America.

It lives in glacial streams and high altitude environments

like in Montana or the Canadian Rockies.

Similarly, the habitats are shrinking

due to glacial recession and global warming.

Anthea Nardi: Like the Patagonian insects,

they have evolved to live in extremely cold water.

Their larvae can easily survive in near-freezing temperatures.

The larvae are aquatic and they mature

in the cold glacial meltwater,

adapted to cold temperatures and low oxygen.

So could the creatures found in Patagonia be stoneflies?

Dr. Riskin: That's a really strong possibility.

It looks like a stone fly.

But there's one major difference,

this Patagonian creature doesn't have wings.

Narrator: With nothing else to clarify the discovery,

the biologists come to an exciting conclusion.

James Ellis: It's a newly discovered species!

A relative of the stone fly

dubbed the Patagonian Ice Dragon.

These creatures feed off particles of algae and dust

made up of microbes and other particles that accumulate

on top of ice glaciers called Cryoconite,

and they live their entire lifecycle on the ice.

Dr. Riskin: What's incredible is that their eggs are invisible.

And because those eggs are invisible,

you can see the babies inside the eggs as they grow,

and they look like miniature versions of the adults.

That's weird because normally a baby insect

looks like a maggot!

Not these ones!

James Ellis: By the time the females lay the eggs,

they've already fully developed.

However, how they emerge from the eggs is still a mystery,

since they're so hard to see,

thanks to their translucent colour,

until they mature and the exoskeletons become darker.

Narrator: The discovery of the Patagonian Ice Dragon

is opening up a whole new area of study,

that has the biologists excited.

Dr. Leonard: The scientist who's been at the forefront of this

research has been observing the Ice Dragons full time during

his research at the laboratories in Argentina and Chile.

His next step is to start a captive breeding program,

to help save the species before its ecosystem disappears.

Dr. Riskin: Insects are the most diverse animals on the planet.

Without them, humans would not be able to survive,

and yet we take them for granted.

We overlook them when they are extremely useful

for understanding how our planet works.

And in this case, they really are the canary in the coal mine.

Narrator: Small communities of insects

like the Patagonian Ice Dragons,

are fundamental in the exchange of nutrients

within the glaciers in the ice fields,

and can warn us about changes in their habitats.

The more we know about these creatures,

the better prepared we'll be for whatever the future holds.

Narrator: Shaped by millions of years

of geological transformations,

Taylor Valley is the most southern part of

the McMurdo Dry Valleys in Antarctica and one of

the most remote and geologically unique places on the planet.

James Ellis: Considered one of the driest places on earth,

Taylor Valley is largely free of ice and snow,

but still experiences severe cold temperatures

as low as -92°F.

Dr. Riskin: The McMurdo Dry Valleys are called dry valleys

because they're literally deserts.

Vegetation is really sparse,

it doesn't rain or snow much at all.

and you've got these really strong winds

that dry the environment out,

just like winds do in traditional hot deserts.

A. Nardi: Home to Taylor Glacier and surrounding ice sheets,

the area is extensively studied and researched,

valued both for its unique environment,

and as a key indicator of wider global processes

like climate change, weather systems and much more.

Narrator: As one group of scientists studies

the endless ice sheets,

they notice something that catches their eye.

Dr. Riskin: The snow on top of the ice sheets is covered with

these small circular holes that take up about

4% to 6% of the entire ice surface.

They're scattered all over the place,

there's really no discernible pattern.

It's kind of like the spots on a Dalmatian.

Dr. Agbedor: The holes vary in diameter from 2 to 57 inches,

and can get as deep as 22 inches.

But there are also a few very large ones,

getting up to 60 feet deep and 98 feet wide.

So what created them?

Anthea Nardi: When you think of holes in the ice,

you can't help but think of Polynya holes,

which translates from Russian to mean, 'hole in the ice.'

If you think of the McMurdo Dry Valleys as a desert,

the Polynyas are like an oasis.

Narrator: Polynya holes are sizable, naturally occurring

areas of open water completely encircled

by sea ice in polar regions.

The most significant of which is the Weddell Sea Polynya,

first identified by remote sensing satellites in 1974.

The Weddell Sea Polynya reappeared only intermittently

in the decades that followed,

but in 2016, it showed up with a vengeance,

swelling to over 15,000 square miles.

Dr. Riskin: Polynya holes form in two ways,

both of which involve heat.

There's something called a sensible heat Polynya,

that's created when warm water rises to the ocean's surface,

maintaining a temperature that prevents the ice from forming.

The second kind is called a latent heat Polynya.

And those formed when ocean currents or the wind,

push the ice away from a fixed location,

so you can't get ice there either.

Both ways, you get a hole in the ice,

and both of those are called Polynyas.

Dr. Agbedor: They have a very important role in our ecosystem.

Their presence can impact the surrounding sea ice

by influencing ice formation and melting patterns,

affecting the overall dynamics

of sea ice coverage in polar regions.

They also provide habitats for various species,

such as seals and penguins.

And the open water allows sunlight

to generate a diverse range of marine life.

Anthea Nardi: While Polynyas can happen in areas

surrounding or adjacent to ice sheets, it's not typical.

And these mysterious holes and questions are appearing

all over the McMurdo Dry Valley ice sheet.

James Ellis: Polynyas also typically require

specific environmental conditions,

such as strong winds and warm ocean currents,

to create and maintain open water areas surrounded by ice.

While there are strong winds, there are very dry winds,

and Polynyas usually form in a coastal open water,

or sea ice environment.

So it's unlikely that Polynyas would form in Taylor valley.

Narrator: With Polynyas ruled out, the scientists

look for answers within the animal kingdom.

Dr. Agbedor: These holes could have been created by animals

living under the glaciers,

like seals, for example.

Seals create breathing holes to catch their breath

and access air while they're swimming,

or resting under the ice.

Anthea Nardi: They typically create the holes

using their claws and teeth, scratching and biting

at the ice to break through.

Then they maintain the holes by continuously coming up for air

and using their bodies to keep the hole

from freezing over completely.

Dr. Riskin: Where they place these breathing holes

is also really strategic.

Seals have this really weirdly good ability

to find those holes over and over again.

They have this spatial awareness

that's on par with the way we use GPS.

We don't know how they do it, but they may use something

that involves the Earth's magnetic fields.

James Ellis: But even though there are Weddell seals

that live close by in the McMurdo Sound,

not many of them make the long trek to the Taylor Valley.

If they do, things don't always end well for them.

Without other species and food to eat in the dry valleys,

they don't last long due to the desert-like environment.

In fact, some of these seals can die and become mummified.

One was found to be 2,600 years old!

Narrator: Searching for answers, The team extracts core samples

from the holes and studies them under a microscope.

What they see is a big surprise.

Anthea Nardi: There are thriving communities of microorganisms,

including different species of tardigrades,

nematodes and rotifers, just to name a few.

This is really surprising.

Each of these holes functions like a small island,

hosting its own unique ecosystem and habitats.

They are teeming with bacteria and algae,

which supply essential nutrients

for the tiny microscopic creatures.

J. Ellis: These are definitely cryoconite holes,

small circular melt-holes found on the surface

of glaciers and ice sheets.

The unique dry and dusty conditions of the valley,

make it an ideal environment for cryoconite holes to form.

Dr. Agbedor: These holes most likely started

as small circles of black dust,

soot or organic matter landing on the icy surface.

Because of their dark color,

they absorb the sunlight easily

and the ice underneath melts,

creating a small pool with a layer of silt,

made up of sand and clay at the bottom.

Dr. Riskin: Now the dust and soot that create these holes,

most of it probably comes from this area.

But there is an example of a scientist

who took a soil sample from a glacier in Antarctica,

and what grew out of that soil sample was a fern,

that is normally only found in Africa.

So the dust could be from anywhere on the planet.

Narrator: While cryoconite holes have some incredible attributes,

some scientists think they have negative implications as well.

James Ellis: Because they cause the ice to melt more rapidly,

they accelerate the sinking of the glaciers.

Also, during the refreeze process,

pressure can build up and cause fractures

in the surrounding ice, creating early channels.

These localized depressions can influence ice flow patterns

and the overall stability of the glacier.

Narrator: Although some experts are concerned about

cryoconite holes speeding up the melting of glaciers,

others are more interested

in the possibilities of exploration.

James Ellis: Some researchers believe that the microorganisms

in the holes might carry secrets

that could unlock how to survive

in extreme environments such as on another planet.

There are also some theories,

that they are distinct ecosystems

with their own boundaries,

energy flow and nutrient cycling.

Especially because some species only exist in cryoconite holes.

Dr. Riskin: Another interesting idea is that someday

these tiny creatures that are found inside the holes

could jumpstart the colonization of land

left bare by the melting glaciers.

They contribute to nutrient cycling,

they contribute to soil formation, and ultimately,

that's the beginning of the whole ecological succession

that's going to create these new ecosystems

we can't even imagine.

Narrator: While the cryoconite holes might not look like much,

they're homes to distinct, fascinating species,

that could one day help humans survive,

in the most extreme conditions.

More studies need to be done on cryoconite holes,

and reveal their effects on glacier biogeochemistry,

and the world at large.

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