By Ashik Siddique | May 06, 2013 11:58 PM EDT
New analysis suggests that Australian megafauna were wiped out by climate change in the late Pleistocene era; Aboriginal human activity was not the primary cause of the massive animal extinction.
By Makini Brice | Dec 17, 2012 02:47 PM EST
About 251 million years ago, 90 percent of the Earth’s species became extinct.
