Over-Hunting Walruses Likely Forced Vikings to Abandon Greenland

Illustration for article titled Over-Hunting Walruses Likely Forced Vikings to Abandon Greenland
Photo: NOAA

Scientists have struggled to understand why, after hundreds of years, Vikings suddenly abandoned their Greenland colony. New research suggests their economic over-reliance on walrus tusks—a valuable but dwindling trade commodity—had a lot to do with it.

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Viking settlements in Greenland were established by Erik the Red around 985 CE. This Norse colony lasted for centuries, but it was abandoned in the 1400s for reasons that remain unclear. Archaeologists and historians have tossed a bunch of possibilities around, citing climate change, communicable diseases, and unsustainable farming practices as possible reasons.

New research published in Quaternary Science Reviews now adds color to another possible explanation: the Viking over-exploitation of walruses in Greenland and the collapse of walrus ivory as a valuable commodity in Europe. The first author of the study, James Barrett from the University of Cambridge, isn’t saying this is the only reason why the Vikings had to abandon Greenland, but he and his colleagues believe it was a major contributing factor.

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Indeed, without much to offer Europe in terms of trade, the medieval Greenlanders used walrus tusks to power their economy. Europeans happily traded goods such as iron and timber for the ivory, which they used to make elaborate jewelry, chess pieces, and other ornate items, according to the researchers.

Over time, however, this proved to be an unsustainable way to maintain an economy. By the 11th century, practically all ivory traded across Europe came from Greenland, the authors note. Eventually, however, the ivory had to be sourced from increasingly smaller walruses, as well as those living far away from the Norse colonies in southeast Greenland.

A walrus rostrum, or upper jaw bone, with tusks.
A walrus rostrum, or upper jaw bone, with tusks.
Image: Le musée Vert, Le Mans

In an email to Gizmodo, study co-author Bastiaan Star from the University of Oslo said walrus trade has long been considered an important element of the Norse Greenland economy.

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“So far, it has been unclear what the potential impacts of such trade may have been,” Star told Gizmodo. “We find evidence suggesting that smaller animals—and more females—were harvested during later periods, and that these animals have been taken further and further away from the settlement in the south. Such observations reflect classic patterns of over-exploitation.”

Exacerbating the Vikings’ troubles, African elephant tusks started to arrive in Europe by the 13th century, and they soon became more popular than the walrus tusks.

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“Elephant ivory is bigger, and the smaller size of walrus ivory constrains what you can do with it,” said Star. “Also, elephant ivory is consistent all the way through, whereas walrus tusks have a different color in the middle of the tusk.”

That a connection existed between the walrus ivory trade and the demise of Norse Greenlanders has been entertained by scientists before.

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“But the main theory has been that walrus ivory hunting and trade declined from the 1200s, when elephant ivory became the preferred medium for carving in Europe,” wrote Barrett in an email to Gizmodo. “Our discovery is the reverse—that hunting probably increased then. We think it must have been because the unit value of walrus ivory declined, and the Norse Greenlanders still had need to keep up trade with Europe. So they actually had to hunt more animals.”

Rostra fragments used in the study.
Rostra fragments used in the study.
Image: J. H. Barrett et al., 2020
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Much of this evidence was gleaned through analyses of medieval rostra—the part of the walrus body that encompasses both the snout and skull. In total, the researchers were able to acquire 67 rostra from various sites across Europe dating back to between the 11th and 15th centuries. Once at the ivory workshops, these rostra were broken up into smaller pieces, distributed, and processed into various goods.

“We have evidence that these rostra were used as ‘packages,’” said Star. “Specific modifications made it easier to eventually ‘snap off’ tusks when transported. Some of these rostra were kept throughout the ages, surviving in various collections as exotic items. Others were obtained from archaeological excavations. Most of them came from cities, such as Trondheim, Bergen, and Dublin, which were known to have played a role in the ivory trade.”

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These rostra samples allowed for DNA, isotopic, and morphological analyses, which the researchers used to determine the animals’ genetic lineage, geographical origin, size, and sex. The researchers supplemented this data by studying artifacts made from walrus ivory in Europe during this period, placing the items in a historical context.

“Specific manufacturing techniques point to a remarkably consistent set of modifications that were applied in a chain,” explained Star. Not all of the skulls received the same types of modifications, and the skulls appear to have been modified more extensively during the later periods, he said.

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Map showing Viking settlements and areas explored by hunters in search of walruses.
Map showing Viking settlements and areas explored by hunters in search of walruses.
Image: J. H. Barrett et al., 2020

Analysis of the rostra showed that the walruses got increasingly smaller over time, and they were sourced farther north, including from areas inhabited by an evolutionary lineage found exclusively in Baffin Bay. The researchers saw a “significant increase of exactly that type of walrus during the settlement period of the Greenland Norse,” said Star. Having depleted the local populations, and needing more ivory to keep up with the African elephant ivory trade, the Vikings ventured farther north to Smith Sound in search of more walruses.

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Fascinatingly, archaeological evidence presented in the new paper bolsters this claim; remnants of the Vikings, namely rivets from a Viking boat, were previously found in an Inuit community living far north on an islet of Ellesmere Island. This “is very far north indeed, in comparison to the Norse settlements which were in south-western Greenland,” said Barrett. “The Norse went that far for a reason.”

This strategy seems to have worked—at least for a little while. Evidence suggests a surge of walrus ivory arrived in Europe during the 13th and 14th centuries.

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But the Viking colony in Greenland wasn’t meant to be, as the walruses became increasingly hard to come by and Europeans increasingly turned away from walrus ivory. As the new study points out, practically no evidence of new walrus ivory imports exists in Europe after 1400. With their economy in ruins, the Norse Greenlanders were forced to leave their colonies, according to this interpretation.

Nicolás Young, an associate research professor from Columbia University who’s not affiliated with the new study, said it’s becoming increasingly obvious that socioeconomic factors, and not the climate, resulted in the demise of Vikings in Greenland.

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“The demise of the Norse in western Greenland has long been a hot topic, and whether right or wrong, Norse demise in Greenland has been used a poster child of climate-driven societal collapse,” wrote Young in an email to Gizmodo. “I think people have naturally gravitated towards a relatively straightforward explanation of why the Norse disappeared from Greenland: ‘It was the climate.’ However, I think over the last decade or so it has become fairly clear that socioeconomic factors almost certainly played a large role in dictating Norse migration patterns, perhaps even more so than any changes in regional climate.”

Young’s research from 2015 added new evidence to further discredit the climate explanation. He and his colleagues showed that Greenland wasn’t significantly affected by the Middle Warm Period, as opposed to other parts of the globe, and that the ensuing Little Ice Age, a period of colder weather, did not force the Vikings to abandon their Greenland colony, as some scientists believe.

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“I think this study here is another piece of puzzle that strongly supports the overall idea that changes in climate may not have been the main driver behind Norse demise in Greenland,” said Young. “If you over-hunt walrus, and the harvested ivory becomes less valuable, then eventually the Norse are going to lose one of the main economic reasons to be in Greenland. It is simply not worth it to them anymore.”

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Simple, uni-causal explanations, while attractive, rarely tell the entire story. In this case, the demise of the walrus ivory trade was likely exacerbated by other factors that caused the Vikings to leave Greenland, including the Black Death, soil erosion caused by overgrazing, and possibly even conflicts with the Inuit. As history shows, people are often reluctant to leave their homes, and it takes a lot for a community to finally call it quits on a region.

George is a senior staff reporter at Gizmodo.

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DISCUSSION

Well, they don’t seem to have learned anything from Iceland.

Another example of over-exploiting a wild stock until it becomes so rare that it isn’t profitable to make a special effort to harvest it any more, or extinct. Funny that free-market economic models don’t seem to account for this. Instead we get horseshit about fungibility.