Far North Science

Colors of the arrows show their timing. The initial peopling of Berinigia
(in light yellow) was followed by a standstill. Then the ancestors of
Native Americans spread swiftly all over the New World. More recent
migration (shown in green) shows back-migration into Siberia and the
spread of D2a into north-eastern America.
Source: Image courtesy Ripan Mahli

Alaska may be the cradle of the New World.

A new study suggests that ancestors of the very first Americans may have cooled their heels during the height of the ice age in the Beringian steppes of western Alaska and northeastern Siberia, remaining in the Far North for thousands of years before suddenly trekking south to seize the continent from woolly mammoths and bison.

These prehistoric Alaskans could have been in Beringia as early as 30,000 years ago — long before the continental ice sheets melted — subsisting in a long-gone ecosystem of fabulous giant mammals. They also carried a surprising amount of diversity in their genes.

But once these prehistoric Beringians decided to move south, they did so with a vengeance, migrating all the way to the tip of South America within a few generations.

“The ancestors of Native Americans who first left Siberia for greener pastures perhaps as much as 30,000 years ago, came to a standstill on Beringia,” explains an online story from the University of Illinois, “and they were isolated there long enough — as much as 15,000 years — to maturate and differentiate themselves genetically from their Asian sisters.

“After the Beringian standstill, the initial North to South migration was likely a swift pioneering process, not a gradual diffusion.”

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Woolly Mammoth
Credit: Wikipedia Commons

Once upon a time, the prehistoric steppes of North America hosted a menagerie of giant mammals — woolly mammoths, saber-toothed tigers, cave bears, camels, horses, lions, giant ground sloths as well as bison, moose, musk-oxen and even spear-chucking humans dressed in fur.

As any video-watching child knows well, the late centuries of the ice age fairly rocked with these immense beasts and their furry companions.

And then, about 13,000 years ago, most of this fabulous megafauna rapidly died out. Mammoths went extinct. Lions and tigers and horses and sloths disappeared. Scientists have long debated the causes.

Was it overhunting by Pleistocene humans with spears, wild fire and shrewd killing strategies? Or was it a sudden shift in the climate that destroyed the productive grassy steppe that supported this network of grazers and their predators?

Now, an international team of scientists led by Richard Firestone of Lawrence Berkeley National Laboratory has uncovered evidence that an immense explosion — accompanied by a nuclear-strength shockwave — triggered a catastrophic climate shift that wiped out life across America. The work follows up on earlier findings by Firestone that a supernova 41,000 years ago may have created a killer space rock and sent it tumbling into the home planet.

In other words, just like the dinosaurs before them, the mammoths may have been fried by an asteroid.

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Remains of bearded seal (Erignathus barbatus) of all ages
have been recovered from the Amaknak Bridge site on
the Island of Unalaska in the eastern Aleutians. Shown
here are mandibles from a fully mature prehistoric
adult and a pup several weeks old (top). Bearded seals
give birth on sea ice in early April and nurse their young
for about three weeks.

Winter ice once clogged the Bering Strait until late summer and surrounded the rugged shores of the Pribilof Islands most of the year, according to a new study of ancient animal bones at an Aleutian archeaological site.

This frigid climate, occurring during a mysterious 2,000-year-long cold snap that ended about 2,500 years ago, was powerful enough to trigger decisive shifts in the migrations of whales and the breeding habits of Northern fur seals, ultimately creating a thriving ecology very different than the one observed during the past few hundred yeaers.

Two Canadian archaeozoologists — Susan Crockford and Gay Frederick of Pacific Identifications Inc — say the findings suggest a startling conclusion: that marine mammals like seals may be far more adaptable that people realize.

“Sea ice not only extended further south than it does today but persisted longer into the summer,” they added. “No other type of evidence has documented an expansion of sea ice in the Bering Sea during this time period, which appears to explain the prehistoric distribution of at least one North Pacific marine mammal.”

Among other things, the two scientists found remains of a newborn bearded seal pup, an ice seal, suggesting that floes existed near Unalaska Island as late as April.

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Inupiat hunter butchers a caribou
NOAA Photo Library

Scientists investigating climate and biology in Alaska and the Arctic have slowly discovered a reservoir of essential background knowledge — the observations from Native residents.

Listening to the people who gather food on the land and sea opens a door on past conditions and can help put the present into perspective, according to an news story that appeared recently in the journal of Science.

Certainly, scientists must be careful with anecdotes and be alert to bias, the article points out. But with a satellite record only 30 years old, and other data going back only a few generations, tapping Native memory has become an ingenious tool for extending research into climate change, sea ice, storm tracks, marine mammal populations, fish runs, bird migration and vegetation shifts.

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When a species goes extinct, sometimes fossils can be found, remains uncovered. The presence of DNA might allow scientists to decipher the biological essence. We know the Stegosaurus. We can study the Wooly Mammoth.

But when a human language disappears, especially one spoken by indigenous tribal people, there’s rarely any key left behind. For most of the world’s 6,000 languages, writing samples are sparse, recordings rare. One by one, they’re going silent. Each loss becomes a linguistic black hole, where an entire way of knowing the world gets trapped out of hearing, gone forever.

Nearly all of them could be extinct in the next two centuries, says University of Alaska Fairbanks professor emeritus Michael Krauss.

“I claim that it is catastrophic for the future of mankind,” Krauss said during a session on the phenomena of extinction at the American Association for the Advancement of Science annual meeting in San Francisco. “It should be as scary as losing 90 percent of the biological species.”

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A villager once called it “next door to heaven,” a rocky islet with stilt homes perched on its steep slope, amid the bountiful Bering Sea.

Ukivok Village in 1978
NOAA Photo Library

Now an Oregon-based research team has recovered evidence that a village flourished 800 to 900 years ago on King Island, suggesting that Inupiat walrus hunters inhabited the tiny island 40 miles off the coast of Alaska’s Seward Peninsula for at least a millennium.

The multi-disciplinary group of scientists, led by OSU anthropologist Deanna Kingston, confirmed the age of materials at the village site using carbon dating techniques.

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