BEARS lived alongside humans in Ireland for thousands of years, according to new research using radiocarbon dating.

It had been thought that bears disappeared from the island in about 5,000BC, but a forensic study of bones found in Leitrim has established that they survived until at least 2,000BC, millenniums after people arrived and long after the introduction of farming.

When man first arrived in Ireland, in about 8,000BC, the island was covered with dense elm, hazel and pine forests that were home to bears, lynx and wolves. The brown bears were the same species as the aggressive grizzly of North America, which can weigh more than 700kg (1,500lb) and feeds on roots, berries and fish, but also deer and livestock.

The bones of what may have been the last Irish bears were found in 1997 in the Glenade valley in Leitrim, in a cave on an almost-vertical cliff that was probably a wintering den. The bones are now on display at Marble Arch caves.

Nigel Monaghan, keeper of natural history at the National Museum of Ireland, told a scientific conference in Cork this weekend that the bones have been dated to between 2,000BC and 1,000BC.

Professor Pete Coxon, of the Department of Geography at Trinity College, Dublin, said: “People were really beginning to have an incredible impact on the landscape by that time. With more demand for wood, you see large-scale disappearance of the forests.”

Bears may have lived in Ireland for more than 35,000 years. Some bear bones date to between 25,000 and 40,000 years ago, when the country had a cold tundra environment and was populated by mammoths, reindeer and giant deer. Bears may have survived an intensely cold polar period from 25,000 to 15,000 years ago, but this is uncertain since no remains have been found from this time.

“In south Munster, there were no significant ice sheets, but there is a question over how habitable it was south of the glacial front,” said Monaghan. Scientists remain puzzled as to whether animals became extinct during this icy period and subsequently recolonised Ireland via land bridges across the Irish Sea, or clung on south of the ice.

Ceiridwen Edwards, of the Smurfit Institute of Genetics, an expert on ancient DNA, has succeeded in isolating DNA from the remains of 17 Irish bears from all over the island. By comparing the DNA in bones from different times, she hopes to say whether one bear population persevered or whether the species repeatedly recolonised the island.

The Natural History museum first began its collection of bear bones in the 19th century. In 1852, a bear skull uncovered during drainage work near the Boyne river was delivered to the curator, William Wilde, father of Oscar. New DNA techniques have meant old bones are now being dusted off for analysis and they are yielding new insights.

In this way, scientists can say whether or not the bears were closely related.

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