They didn’t rape and pillage or wear horned helmets, but Norwegian mice accidentally stowing away on Viking ships swept through almost as many countries as the fearsome humans whose ships they boarded.
That’s the conclusion from an analysis of mitochondrial DNA (mtDNA) from modern house mice (Mus musculus domesticus) living on Iceland and Greenland, which was compared with mtDNA extracted from mouse skeletons on the islands dating to the Viking heyday, 1000 to 1200 years ago. The sequences were also compared with mtDNA sequences from Viking mice in Norway and the UK.
“We show they got as far as Greenland,” says Eleanor Jones of Uppsala University in Sweden, who led the team.
On Iceland, the Viking mice are still thriving. The mtDNA extracted from Viking mice skeletons there was easy to trace in today’s Icelandic mice, mainly because the relative isolation of the country means that there have been few subsequent mouse invasions. “It’s exactly the same mitochondrial DNA, reaching right through from the ninth century to the present day,” she says.
It is unlikely that Viking mice made it as far west as Newfoundland, because only around 20 Vikings ever reached the island – and they probably stayed for only a year. However, Jones’ team lacked ancient mice from the island to test this.
In earlier research, Jones demonstrated how the Norwegian mice colonised much of the British Isles and Ireland. She says that they probably stowed away by accident in hay and grain kept in the ships for domesticated animals.
Journal reference: BMC Evolutionary Biology, in press
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