L’#ours blanc était roux // Polar bear ancestors came from Ireland | Science | The Guardian
►http://www.guardian.co.uk/science/2011/jul/07/polar-bear-ancestors-ireland
Modern polar bears share a distinct DNA sequence, passed down the female line, with their now extinct brown ancestors. However, the same DNA fingerprint is absent from other species of brown bear alive today.
It is thought the link arose from interbreeding between prehistoric polar bears and female brown bears when their paths crossed as the Irish climate cooled.