Tenth- or eleventh-century fragments of mouse bone found in Madeira, along with mitochondrial DNA of Madeiran mice, may indicate that the Vikings have come to Madeira (bringing mice with them), prior to colonisation by Portugal.
Tenth- or eleventh-century mouse bone remnants and mitochondrial DNA from Madeiran mice found in Madeira could imply that Vikings had visited the island (carrying mice) prior to Portugal's colonization.