Economy, not environment, did in the Vikings

New research published this month pushes back on the environmentalist claim that climate change destroyed the Viking outposts of Greenland. The study, published last week in the journal Proceedings of the Royal Society B, tells of a changing economic climate, not climate change.

In the mid-12th century, a flourishing Viking settlement existed on the massive island of Greenland. The Norse community secured its own bishop and paid their tithes in walrus tusks. Archaeological ruins from the era include a monastery and elaborate church buildings boasting bronze bells and stained glass. Scientists have unearthed ornate crucifixes, knife handles, fancy dice, and chess sets carved from walrus tusks. But by the end of the 15th century, the Greenland Vikings mysteriously vanished.

Because the disappearance of these Norse outposts coincided roughly with the beginning of the Little Ice Age, an era of cooling temperatures, many environmentalists have concluded climate change wrought the Vikings’ demise and have latched onto the story as an object lesson for today.

In a 2005 interview about his book, Collapse, American anthropologist Jared Diamond told The Guardian the Vikings sealed their own fate because they did not heed climate change and amend their ways: If they had not stripped their land of trees they would have had wood to burn. If they had fished, instead of keeping cattle that often could not survive the Greenland winters, they would not have starved. And if they had traded tusks and hides for tools and food instead of religious artifacts, they could have prepared better for climate change.

Now scientists for the first time have analyzed DNA samples from fragments of walrus skulls housed in more than a dozen European museums, and the results surprised them. The evaluation indicated the vast majority of ivory in all of Europe at that time came from Greenland. It turned out the Vikings were prolific traders of ivory throughout Europe and likely enjoyed a highly lucrative monopoly on the precious commodity.

“Until now, there was no quantitative data to support the story about walrus ivory from Greenland,” Bastiaan Star, co-author of the study, said in a statement. “Walruses could have been hunted in the north of Russia, and perhaps even in Arctic Norway at that time. Our research now proves beyond doubt that much of the ivory traded to Europe during the Middle Ages really did come from Greenland.”

Scientists now suspect factors such as a European change of taste for elephant ivory or the onset of the Black Plague led to a collapsing ivory market and economic ruin for the Greenlanders. Thomas McGovern, an anthropologist at Hunter College in New York said the new research is “changing the story that we’ve been telling for years.”

iStock.com/BasieB

Darwin’s abominable mystery remains

The Bible forbids marriage and mating between close human relatives, but it seems God also designed many flowers with a mechanism to prevent inbreeding.

Charles Darwin called the origin of flowering plants an “abominable mystery,” and current research continues to leave Darwin’s followers in the dark. Flowering plants contain both male and female components within the same plant—the male component produces pollen, which germinates on the female component, the stigma.

A plant’s stigma produces a substance toxic to its own pollen but not to the pollen of others. And pollen has an antidote to all other plants’ toxins except its own. The toxins and antidotes prevent inbreeding and allow genetic diversity to flourish.

Evolution could only produce that mechanism if the mutation that enables the stigma to make the toxin occurred at the same time as the mutation that made the pollen’s antidote. But scientists remain unable to explain how this co-evolution could happen, since they believe a random process produces genetic mutations.

In a study published last month in the journal Genetics, a team of evolutionary geneticists, game theorists, and applied mathematics experts at Austria’s Institute of Science and Technology attempted to solve the mystery through theoretical computer simulations. But when they matched their predictions with real world data, they found the diversity of genes in their theoretical simulations was much lower than those found in nature. In a statement, the researchers said they were left with many more questions, and “the mystery of the high diversity in nature still exists.” —J.B.

iStock.com/BasieB

Salty snacks are back

After years of warnings from health experts to reduce sodium intake, salt may be back on the table. Refuting the World Health Organization’s recommendation that daily sodium intake should not exceed 2 grams, a large, ongoing observational study, published last week in The Lancet, found up to 5 grams (2.5 teaspoons) of sodium per day does not increase health risks. Fewer than 5 percent of individuals in developed countries consume more than that. According to the research, increased sodium intake for people who stayed under 5 grams per day appeared to decrease their risk of heart attacks and death.

“Only in the communities with the most sodium intake—those over 5 grams a day—which is mainly in China, did we find a direct link between sodium intake and major cardiovascular events like heart attack and stroke,” lead researcher Andrew Mente of McMaster University in Hamilton, Ontario, said in a statement.

More good news: The researchers found that those who consume more than 5 grams per day can virtually eliminate the health risk by adding fruits, vegetables, dairy, potatoes, and other potassium-rich foods to their diets. —J.B.

People buried at Stonehenge likely helped build it

Until now, scientists have known very little about the cremated human remains buried at Stonehenge, the prehistoric stone circle monument, cemetery, and archeological site in the Wessex region of England. But a recent study, appearing in Scientific Reports, found some of those buried at the site likely moved to the region from the Preseli Mountains of West Wales and brought with them the bluestones used in the early stages of the monument’s construction. New developments in archeological science allowed the researchers to extract chemical information from the skull bones of 25 individuals buried at the site. The results showed at least 10 of the people did not live near Stonehenge prior to their death, but likely lived in a region that includes West Wales, the source of Stonehenge’s bluestones. —J.B.

Why elephants don’t get cancer

The bodies of the largest living land mammals would seem like a great place for malignant tumors to grow, but elephants seldom get cancer, and researchers at the University of Chicago recently set out to discover why.

Their results, published in the journal Cell Reports, show that when an elephant’s DNA suffers damage, such as that caused by mistakes during cell division or harm from ultraviolet rays, the elephant produces a protein that suppresses the growth of tumors. The protein wakes up a zombie gene called LIF6 that in turn kills cells poised to become cancerous.

The researchers hope the new discovery will aid cancer treatment in humans. “Maybe we can find ways of developing drugs that mimic the behaviors of the elephant’s LIF6 or of getting cancerous cells to turn on their existing zombie copies of the LIF gene,” Vincent Lynch, one of the researchers, said in a statement. —J.B.