Demise of ancient giant beasts mainly caused by humans: UK scientists

A team of British researchers announced Thursday that their research indicated early humans were the dominant cause of the extinction of many ancient giant beasts.

Researchers at the universities of Exeter and Cambridge claimed that their research settled a prolonged debate over whether mankind or climate change was the dominant cause of the demise of massive creatures in the time of the sabretooth tiger, the woolly mammoth, the woolly rhino and the giant armadillo. The research also involved the universities of Reading and Bristol.

Known collectively as megafauna, most of the largest mammals ever to roam the earth were extinct as of 10,000 years ago.

By using cutting-edge statistical analysis, researchers said they ran thousands of scenarios which mapped the windows of time in which each species was known to have become extinct, and humans were known to have arrived on different continents or islands. This was compared against climate reconstructions for the last 90,000 years.

Examining different regions of the world across these scenarios, they found coincidences of human spread and species extinction which illustrated that man was the main agent causing the demise, with climate change exacerbating the number of extinctions.

However, in certain regions of the world -- mainly in Asia -- they found patterns which were broadly unaccounted for by either of these two drivers, and called for renewed focus on these neglected areas for further study.

This research is "the nail in the coffin of this 50-year debate", and humans were the dominant cause of the extinction of megafauna, said Lewis Bartlett, who led the research.

Bartlett also said: "What we don't know is what it was about these early settlers that caused this demise. Were they killing them for food, was it early use of fire, or were they driven out of their habitats?"

The research paper has been published in the journal Ecography. Endit