Picture, if you will, a ship full of fierce, angry Vikings. They’ve spent countless days at sea, and they’re ready for some serious pillaging. They drop anchor, heave their axes, and burst upon the land with a wave of destruction that gains them a fearsome reputation for generations to come…
…and as the men sweep through villages and plunder women and livestock, another invader quietly slips down the ropes of the docked ship, or hides in sacks and crates until reaching the shore, where they creep off into dark corners or small holes, infiltrating the land in a way only they know how.
Ah, yes. Rodents. Mice, in particular. Perhaps the cleverest of invaders, or we might say in this case, colonizers. The mice didn’t just arrive with the Vikings to eat food and take over land, but rather, they looked around, thought the place seemed like a decent enough neighborhood to raise kids, and stuck around.
Between the late 8th and mid-10th centuries AD, Viking invaders took over land and settled their own people in many regions, including France, Scotland, England, Ireland, Iceland, Greenland, and Newfoundland. While house mice are known to have lived alongside humans from as early as 8,000 B.C. in the Ancient Near East, they evidently did more than that—they traveled and moved with humans at the same time.
To learn this, scientists compared the DNA of modern mice with that of mouse remains found on archaeological sites at these Viking-settled locations. It turns out that the mice hitched a ride on Viking ships from Norway or the northern British Isles (which were settled early by Vikings). DNA samples of ancient Viking house mice were found at nine sites in Iceland and several in Greenland, though surprisingly none seem to have made it over to Newfoundland.
It’s thought that the mice hid in hay bales and other crates of food supplies.
The study’s leader, Dr. Eleanor Jones (University of York and Uppsala University), says that "human settlement history over the last 1,000 years is reflected in the genetic sequence of mouse mitochondrial DNA. We can match the pattern of human populations to that of the house mice." In other words? House mice did just as much raping and plundering of the land as the Vikings did, “mirroring” their invasions!
However, the Viking mice in Greenland were eventually ousted by a Danish mouse species (brought by other human colonisers), and are now extinct.
As for the strange lack of Viking house mice in Newfoundland? Cornell University’s Professor Jeremy Searle postulates that the “absence of traces of ancestral DNA in modern mice can be just as important. We found no evidence of house mice from the Viking period in Newfoundland. If mice did arrive in Newfoundland, then like the Vikings, their presence was fleeting and we found no genetic evidence of it."
Makes you think twice about setting down that mouse trap, hmm?