Woolly mammoths helped to keep the earth warm by filling the atmosphere with methane 13,000 years ago, say scientists.
An international team, led by the University of New Mexico, has claimed that mammoths, along with other large plant eating mammals, may have created about 9.5 million tons of the methane gas each year.
An analysis of ice cores has shown that when they disappeared there was a huge fall in atmospheric methane, which may have caused the last Ice Age, according to the scientists.
They found a “cold event” hit the earth at the same time as methane levels fell.
“The changes in methane concentration seem to be unique. Decreased methane emissions caused by the extinction of New World ‘megafauna’ could have played a role,” the British media quoted the scientists as saying.
Methane is a powerful greenhouse gas.
About 13,400 years ago the Americas were heavily populated by large-bodied herbivores like mammoths, camelids and ground sloths and had a richer array of animals than present-day Africa.
But 2,000 years later 80 per cent of them had vanished.
Their disappearance, accounting for more than 114 lost species, came within 1000 years of the arrival of humans in the New World.
But experts disagree over whether hunters or environmental changes were to blame.
The findings have been published in the latest edition of the Nature Geoscience journal.