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A LARGE set of fossilised mammoth footprints has been discovered that may help solve the mystery of the great beasts’ extinction.

The lack of juvenile footprints suggests that humans were killing woolly mammoths as they spread across North America. Today, African elephant herds that have been heavily poached produce a similar pattern of tracks.

Controversy has long raged over the fate of mammoths, and other large North American animals that had vanished by about 10,000 years ago. Many believe that human hunters wiped the animals out within decades of spreading across the continent. Others blame rapid climate change as glaciers retreated at the end of the ice age.

The site of the new prints, found on the seasonally exposed bed of the St Mary Reservoir in Alberta, Canada, has been radiocarbon-dated at 11,000 to 11,300 years ago. That is just a few hundred years after the first people began to spread widely across North America.

Measurements of the size of the footprints show that only 30 per cent of the herd were juveniles, says Paul McNeil, a doctoral student at the University of Calgary. Studies of African elephants have found such low numbers only in groups stressed by poaching and in decline. Healthy elephant groups normally include 50 to 70 per cent juveniles.