Climate change, rather than humans, may have been responsible for driving the woolly mammoth to extinction, according to a new study.

The study by British and Swedish researchers analysed DNA samples from 300 specimens of woolly mammoths collected by themselves and other groups in earlier studies. Scientists, led by Dr Love Dalen of the Swedish Museum of Natural History, found that the species nearly went extinct 120,000 years ago when the world warmed up for a while. They believe their numbers dropped from several million to tens of thousands, but recovered as the planet entered another Ice Age. The study also found that the decline that led to the mammoth’s eventual extinction began 20,000 years ago when the Ice Age was at its height, rather than 14,000 years ago when the world began to warm again as previously thought. Researchers believe that it was so cold that the grass the creatures ate became scarce.

As the Ice Age ended, the grassland on which the creatures thrived was probably replaced by forests in the south and tundra in the north, speeding up the decline of the species, BBC News reported. The cause of extinction of the woolly mammoth has been hotly debated. Some have argued that humans hunted them to extinction while others have said that changes in the climate was the main reason. Critics of the climate extinction theory have argued that the world warmed well before the creatures became extinct and so that could not have been the cause. However, new results show that mammoths did indeed nearly go extinct between Ice Ages and thus back the view that climate change was the principal cause for their demise. Also, other animals, including humans, became more active after the Ice Age.