Woolly Mammoth: Secrets from the Ice Page #2

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cold snap changed the planet,

and transformed the mammoth

into a titan

capable of thriving in the extremes

of the Arctic Circle.

That change occurred

in a blink of evolutionary time,

and was driven by a perfect storm of

exceptional events on a planetary scale.

For millions of years,

Antarctica had been drifting

southwards to its current position,

sending the southern hemisphere

into a deep freeze.

And South America

was charging northwards.

It crashed into North America,

and this altered the ocean currents

and gave birth to the Gulf Stream.

And the knock-on effect of that was increased

precipitation in the northern hemisphere,

which in lower latitudes fell

as rain, and, in the north, as snow.

While these tectonic events

were changing the face of the earth

and propelling it into an ice age,

there were also changes occurring

on a celestial scale, producing dramatic

fluctuations in the earth's climate.

The earth's distance from the sun

changes over time.

Every 100,000 years, the earth is at its

furthest position from the sun's warmth

and our planet enters a cold phase.

Then there's also variation

in the tilt of the earth on its axis

and that happens over a cycle

lasting 41,000 years,

and affects the degree of difference

in the seasons.

Finally the earth also wobbles

on its axis

on a cycle

lasting about 23,000 years.

When all those planetary factors

coincide, winter takes over,

with ice sheets covering

To glimpse the extreme conditions

that mammoths faced,

I'm visiting a remnant

of one of those immense ice sheets.

This wall of ice marks the point

two thirds of the way up

the Athabasca Glacier,

which is about four miles in length

and feeds off the huge

Columbia Icefield in Western Canada,

but even that would have been dwarfed by

the huge ice sheets of the Pleistocene.

In places the ice would reach

up to 13,000 feet thick.

These glaciers are really beautiful.

Really craggy. You look down into the

crevasses and they're deep blue inside.

They're rivers of ice.

It's incredible to think that most

of that would have been under ice,

with just perhaps a peak of the highest

mountains popping out above the ice sheet.

This is amazing!

Wow! Oh!

The ice sheets locked in so much water

that they created cloudless, blue skies.

At latitudes below the ice,

this provided perfect growing

conditions for shrubs and grasses,

creating a vast grassland,

known as the mammoth steppe.

The steppe proved to be a massive

untapped food supply

for any animal able to adapt

to eating its plants.

This newly available niche

drove the mammoths

to evolve from their origins in the

warmth of the southern hemisphere.

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