Invader mice took a lift with Vikings
Mice hitched a lift with Vikings to mount their own invasions in the 10th century, research has shown.
A genetic study shows that Viking longboats carried the tiny Norse warriors to colonies in Iceland and Greenland.
Scientists compared modern mouse DNA with ancient samples from mouse bones found at archaeological sites.
The analysis showed that the house mouse, Mus musculus domesticus, hitched lifts with Vikings in the early 10th century from either Norway or northern Ireland or Britain.
Descendants of these stowaways can still be found in Iceland where DNA samples were collected from nine sites.
From Iceland, the mice continued their Viking voyages to settlements in Greenland.
However, no trace of the Norse mice could be found in Newfoundland, even though the Vikings are known to have reached the Canadian province.
The researchers focused on mitochondrial DNA which is housed in battery-like powerplants in cells and only inherited from mothers.
It can be used by scientists to trace maternal lineages far back in time.
The research is published in the online journal BMC Evolutionary Biology.