Chickens originated in Southeast Asia and have been domesticated and spread to different regions over the past 8,000 years. DNA analysis has shown that domestic chickens descended from the red junglefowl and have interbred with other species of wild junglefowl. They spread to West Asia, the Near East, Europe, South and East Asia, and the Pacific islands through human migrations and explorations. Vikings even brought chickens with them when they colonized Iceland.