Dairy Farming in Finland began in 2500 BC, according to a University of Bristol study.

Until now, researchers believed that prehistoric dairy farming might not have been possible in such harsh environments, where there is snow for at least four months in a year.

This is the first study to have identified dairy farming at this latitude - 60 degrees north of the equator. The temperatures are equivalent to Canada's Northwestern territories, Anchorage in Alaska, Southern Greenland and near Yakutsk in Siberia.

For the study, researchers used modern techniques to examined residues preserved in fragments of ancient cooking pots from two separate eras and cultures, dating to circa 3900 BC to 3300 BC and circa 2500 BC. They also looked at modern Finnish people's ability to digest milk into adulthood. Finns are the biggest milk drinkers in the world today.

The researchers found the evidence of milk fats in the pots belonging to circa 2500 BC. The same period also marked the transition from a culture of hunting and fishing to the arrival of 'Corded Ware' settlements that witnessed the introduction of animal domestication.

"This is remarkable evidence which proves that four and a half thousand years ago, Stone Age people must have been foddering and sheltering domesticated animals over harsh winters, in conditions that even nowadays we would find challenging," Lead author Dr Lucy Cramp, from the Department of Archaeology and Anthropology, said in a press release.

Researchers said that the genetic analysis of modern Finns showed that they have the required genes to digest milk.

"Our results show a clear link between an incoming pre-historic population, milk drinking and the ability to digest milk in adulthood still visible in the genetic distribution of modern Finland, which remains one of the highest consumers of dairy products in the world," Fellow researcher Dr Volker Heyd said.

The finding is published in Proceedings of the Royal Society B today.