Miocene

Drawing on the most recent fossil evidence, he says that chimps and humans began diverging between 9 million and 8 million years ago.

Scientists did just that when they analyzed the fossilized remains of the world's largest known rodents, which browsed on the riverbanks of Venezuela about 8 million years ago.

He had seen this isotopic shift time and again in fossil horses and other ancient mammals that populated the planet between 6 million and 8 million years ago.

Arm, leg, and foot bones of Kenyapithecus contain features in common with later African apes and humans but not fossils of Asian apes dating to around 12 million to 8 million years ago, McCrossin contends.

I'm sure there was ice in Antarctica 8 million years ago," he says.