Extinction of Icelandic walrus coincides with Norse settlement

Scientists from the Arctic Centre at the University of Groningen have discovered a ‘long-lost’ population of walrus that thrived in the seas around Iceland when it was still a pristine wilderness. This unique population was quickly hunted to extinction by Norse settlers who arrived in Iceland around 1100 years ago. Their motivation was economic profit – walrus ivory was a luxury item and traded vast distances across Medieval Europe. This extinction represents one of the earliest examples of commercially-driven overexploitation of the Arctic’s natural resources; large-scale annihilation of many other Arctic marine-mammal species was spear-headed by Dutch whaling companies who operated out of Svalbard (Spitsbergen) from the early 17^th C.

An Enduring Puzzle: Local Walrus in Iceland?

The existence of walrus in the waters around Iceland - and their apparent disappearance after the arrival of Norse settlers - has long intrigued both scientists and the wider public. Was there a unique Icelandic population of walrus, and if yes, what caused its disappearance – human impacts or natural causes?

Commercial Motives: Early European Resource Extraction at the Arctic Frontier

Walrus tusks were highly-prized and the pure white ivory quickly emerged as a luxury trade good that was exchanged widely across Viking Age and Medieval Europe. The ivory was carved by skilled specialists into beautiful objects that were used in elite circles and church services, with many examples reaching the courts and palaces of the Middle East, India and Central Asia. While the demand was insatiable, ivory could only be obtained at remote Arctic hunting grounds that were scattered across the remotest corners of the North Atlantic. The relentless search for new sources of ivory is thought to have played a key role in the Norse settlement of Iceland, Greenland, and their exploration of Arctic North America.

New Inter-Disciplinary Research

New research, published this week by a team of scientists from the Netherlands, Denmark and Iceland in the leading journal Molecular Biology and Evolution, has attempted to resolve this enduring puzzle. Their work involved:

1. Extensive archaeological and archival research, with numerous place names, archaeological finds and written descriptions in the Icelandic Sagas and other Medieval Literature – these all pointing to active local hunting of walrus by the early Norse colonists.

2. Radiocarbon dating of ancient walrus remains confirmed that (a) a local population of walrus had inhabited the seas around Iceland for many thousands of years, and (b) that they had undergone an abrupt decline and eventual disappearance very shortly after the arrival of the Norse around 870 AD.

3.   Extraction and analysis of ancient and modern DNA from archaeological and contemporary walrus samples also confirmed that the ‘lost’ Icelandic walrus constituted a genetically unique lineage that was distinct from all other historic and contemporary walrus stocks in the North Atlantic.

Wider Significance: (un)sustainable exploitation of Arctic marine resources?

Lead author Xénia Keighley is a PhD researcher at the Arctic Centre: “We show that already in the Viking Age, more than 1000 years ago, commercial hunting, economic incentives and trade networks were of sufficient scale and intensity to cause irreversible ecological impacts on the fragile marine environment”

Peter Jordan, Director of the Arctic Centre, was also a co-author: “Our scientific findings are both exciting and also disturbing – we’ve long assumed that the first large-scale profit-driven annihilation of Arctic marine mammal populations was a more recent phenomenon, spearheaded by Dutch and other European whalers operating out of Svalbard (Spitsbergen) from the early 17^th C. These new insights confirm that European impacts on vulnerable Arctic ecosystems began much earlier and were more profound than we had ever imagined; looking to the future, we need to think much more deeply about whether ‘sustainable exploitation’ of any kind of Arctic natural resource is ever going to be possible.”

Co-Author Morten Tange Olsen is a marine biologist from the University of Copenhagen’s GLOBE Institute: “This is one of the earliest examples of local extinction of a marine resource following human arrival and overexploitation. It supports a growing body of evidence that wherever humans turn up, the local environments suffer massive damage.”

Hilmar Malmquist, one of the paper’s senior authors is clear that much more work needs to be done: “The large collections of old bones housed in the world’s Natural History Museums are starting to provide a remarkable window into the past, thanks to the development of new analytical techniques like ancient genomics, which allow us to precisely reconstruct the impact of past human activities on particular species and even entire ecosystems”

Funding

The research forms part of the ArchSci2020 Project, which is hosted by the University of Groningen’s Arctic Centre, and the universities of Copenhagen, Stockholm and York, and funded by the European Union's Horizon2020 Framework Programme for Research and Innovation (Grant Agreement No 676154).

Key Facts

• The walrus (Odobenus rosmarus) grows to 3 meters in length and live up to 40 years. The male weights up to 1200 kg, while the female is slightly smaller. Both males and females have tusks.
• The walrus occurs throughout the Arctic, divided in two subspecies, the Atlantic and Pacific walrus. The Atlantic walrus occurs in Canada, Greenland, Svalbard and Russia and numbers approximately 30000 animals.
• The Norse of the Viking Age were the first people to settle permanently in Iceland around 870 AD, and later colonised Greenland, where they also hunted walrus for their precious ivory tusks.
• Walrus live in local communities and can be easily hunted at seasonal haul-out sites.