Earth Day
It's been 37 years since Earth Day was first celebrated in the U.S. To mark the holiday, 60 MINUTES takes a look at man's impact on the animal kingdom. We'll find out why grizzly bears may be coming off the endangered species list, and travel to a part of Africa so remote that the gorillas living there have no fear of humans. Plus, see how global warming is affecting penguins and polar bears.









