A herd of pigs has helped archaeologists unearth a set of 12,000-year-old stone tools from the Ice Age that provide the earliest dated evidence of human activity in Scotland.

The team from the University of Reading in UK discovered the ancient Ice Age stone tools at a site in Islay, an island in Scotland. The tools included scrapers used for cleaning skins and sharp points for hunting big game such as reindeer, BBC reported.

The excavation was started in 2009 after pigs foraging along the area uprooted Mesolithic objects. Archaeologists found animal bones, plant remains and a fireplace at the Mesolithic site. On the last day of the excavation in 2013, the team uncovered tools which would have been used 3,000 years earlier.

They may have been made by people of the Ahrensburgian culture, which flourished in mainland Europe towards the end of the last Ice Age, researchers said. Similar sites have recently been discovered in Denmark and Sweden, suggesting the Ahrensburgian people may also have been coastal foragers hunting sea mammals from skin boats.

"The Mesolithic finds were a wonderful discovery - but what was underneath took our breath away," said Steve Mithen, who led the excavation with Karen Wicks of University of Reading. "The Ice Age tools provide the first unequivocal presence of people in Scotland about 3,000 years earlier than previously indicated. This moves the story of Islay into a new historical era, from the Mesolithic into the Palaeolithic," Mithen said.