London, Sep 11 (IANS): Researchers have found that climate change, instead of hunting by humans, was responsible for the extinction of the woolly mammoth.

According to a DNA analysis, the woolly mammoths disappeared much earlier than previously assumed primarily because of change in the world's climate, reported BBC citing the Proceedings of the Royal Society B.

Researchers said woolly mammoths were a dynamic species that went through expansions and migrations.

"The picture that seems to be emerging is that they were a fairly dynamic species that went through local extinctions, expansions and migrations. It is quite exciting that so much was going on," BBC quoted Love Dalen of the Swedish Museum of Natural History as saying.

Researchers in London studied the DNA samples of around 300 specimens from woolly mammoths.

The reason behind the extinction of these gigantic creatures had been the subject of many debates in the past.

While some researchers believed that human hunting was the primary reason that pushed them to extinction, others attributed their extinction to climate change.

They found out that the numbers of woolly mammoths went down from several million to tens of thousands around 120,000 years ago when the world went through a warmer climatic phase.

But the numbers recovered after the earth entered another Ice Age.

The researchers said the mammoth's extinction began 20,000 years ago when the Ice Age was at its peak, rather than 14,000 years ago as previously thought.