Humans hunted Australia's giant

vertebrates to extinction about 40,000 years ago, the latest research published

in Science has concluded.

The cause of the widespread extinction has provoked much debate, with climate

change being one theory.

However, scientists studied dung samples from 130,000 and 41,000 years ago,

when humans arrived, and concluded hunting and fire were the cause.

The extinction in turn caused major ecological changes to the landscape.

The scientists looked at pollen and charcoal from Lynch's Crater, a

sediment-filled volcanic crater in Queensland that was surrounded by tropical

rainforest until European settlement.

They found Sporormiella spores, which grow in herbivore dung, virtually

disappeared around 41,000 years ago, a time when no known climate transformation

was taking place.