The mysterious disappearance of Greenland’s Norse colonies sometime in the 15th century may have been due to the depletion of walrus populations for their tusks, according to a study of medieval artifacts from across Europe.
Founded by Erik the Red around 985 AD after his banishment from Iceland (or so the sagas tell), Norse communities in Greenland flourished for centuries – and even got a bishop – before disappearing around 1400, leaving only ruins.
Recent research by the Universities of Cambridge, Oslo and Trondheim has revealed that almost all of the ivory traded in Europe for centuries came from walruses hunted in marine regions accessible only through Norse settlements in southwestern Greenland.
Walrus ivory was a valuable medieval trade item used to carve luxury items such as ornate crucifixes or figurines for games such as chess and the Vikings’ favorite game Hnefatafl. The famous Lewis chess pieces are made from walrus tusks.
However, the study also shows that the ivory came from smaller, often female, animals over time, with genetic and archaeological evidence suggesting they came from increasingly farther north – meaning longer and more treacherous hunting trips for less reward.
Due to increasingly globalized trade, elephant ivory flooded European markets in the 13th century, and fashions changed. There is little evidence of walrus ivory imports to mainland Europe after 1400.
Dr. James H. Barrett of the University of Cambridge Archaeological Institute argues that the Vikings’ abandonment of Greenland may have been triggered by a “perfect storm” of depleted resources and volatile prices exacerbated by climate change.
“The North Greenlanders had to trade iron and timber with Europe in exchange for exporting mostly walrus products,” said Barrett, lead author of the study published in Quaternary Science Reviews.
“We suspect that declining values of walrus ivory in Europe led to more and more tusks being harvested to keep Greenland colonies economically viable.
Mass hunting may end the use of traditional resting places by walruses. Our results suggest that Norse hunters were forced to venture deeper into the Arctic Circle for ever-decreasing ivory harvests. This would have exacerbated the decline in walrus populations and, in turn, the walrus trade.”
Other theories for the collapse of the colonies have considered climate change-the “Little Ice Age,” a sustained period of lower temperatures that began in the 14th century-as well as unsustainable agricultural practices and even the Black Death.
“Over-reliance on walrus ivory was not the only factor in the demise of the Norse in Greenland. However, if both the population and the price of walrus declined, this must have severely undermined the resilience of the settlements,” says co-author Dr. Bastiaan Star of the University of Oslo.
Analyzing carved artifacts would risk damaging them, so the researchers examined pieces of the rostrum: the skull and snout of the walrus, to which the tusks remained attached during transport, creating a protective “package” that was broken apart in the ivory workshops of medieval trading centers such as Dublin, Trondheim, and Bergen.
In total, the team examined 67 rostra that came from sites across Europe dating from between the 11th and 15th centuries. Ancient DNA (25 samples) and stable isotopes (31 samples) obtained from bone samples, as well as the size of the tusk base, provided clues to the sex and origin of the animals.
Stable isotope analysis was performed by the Dorothy Garrod Laboratory for Isotope Analysis in Cambridge and DNA analysis by the Institute of Life Sciences in Oslo.
The researchers also examined traces of “manufacturing techniques” – changing modes of butchery and skull preparation – to place the walrus remains in the story.
Although it is impossible to determine the exact origin, the researchers noted a shift in European walrus finds around the 13th century toward walruses of an evolutionary branch most common in the waters around Baffin Bay.
These animals must have been chased by ships northwest along the Greenland coast, and more recent specimens were smaller and often female. “If the Greenland Vikings’ original hunting grounds around Disko Bay were depleted, they may have traveled as far as Smith Sound to find enough walrus herds,” Barrett says.
Norse artifacts have previously been found among the remains of Inuit settlements dating from the 13th and 14th century in this northernmost region. A former Inuit camp on an island off Ellesmere Island contained the rivets of a Norse boat – possibly a hunting trip from which the hunters never returned.
“The ancestors of the Inuit occupied North Greenland at the time of the Norse colonies. They probably met the Northmen and traded with them,” Barrett said. “That parts of a Norse boat were found so far north suggests the risks these hunters may have taken in their search for ivory.”
Barrett points out that the Inuit of the region preferred female walruses for hunting, so the preponderance of females in Greenland’s later exports could signify a growing dependence of northerners on Inuit supplies.
He says the hunting season for northern walruses would have been short because the seas were covered with ice for most of the year. “The short window of summer would have been barely enough to row the hundreds of miles north and back.”
The legend of Erik the Red himself may obscure what Barrett calls “ecological globalization”: the hunt for natural resources in the face of dwindling supply. Recent research indicated that Greenland may have been colonized only after the Icelandic walruses were hunted to exhaustion.
Ultimately, the marbled appearance of walrus ivory, highly prized for centuries, fell out of favor with the opening of West African trade routes, and the homogeneous surface of elephant ivory became indispensable in the 13th century.
One account suggests that the Normans used walrus ivory to secure their own bishopric from the King of Norway in the 1120s. By 1282, however, the pope demands that his tithes from Greenland be converted from walrus tooth into silver or gold.
“Despite a significant decline in value, the Rostra evidence suggests that walrus exploitation may have actually increased in the thirteenth and fourteenth centuries,” Barrett said.
“As Greenlanders chased depleted walrus populations further and further north for ever diminishing returns in trade, there must have been a point at which it was no longer sustainable. We believe this ‘resource curse’ undermined the resilience of the Greenland colonies.”
The research was funded by the Leverhulme Trust, the Research Council of Norway and the Nansenfondet.
Julia Hager, PolarJournal