Listen to anthropologist Jim Moore, on what's so important about a Tanzania study that provides the first evidence that chimps use tools to forage for tubers.
Murphy says you could look out the window of the airplane and see the air colored brown as you were flying, even though you're hundreds or thousands of miles from the nearest big city. He talks about the sources of this haze.
Hibernators have an internal clock, a series of chemical reactions controlled by the hypothalamus of the animal's brain. Read more about hibernating animals.