Tens of thousands of years ago, nearly two dozen kangaroo species vanished as part of a great extinction event. Science reporter Ari Daniel says hundreds of prehistoric teeth may now help ...

Tens of thousands of years ago, nearly two dozen kangaroo species vanished as part of a great extinction event. Science reporter Ari Daniel says hundreds of prehistoric teeth may now help ...

In a mass extinction event some 40,000 years ago, Australia lost 90% of its large species. New research suggests climate change played a much smaller role than once thought, though not all agree.