Society & Culture
Bird excrement was once so valuable to farmers that the U.S. government tried to claim all of it. It's possible to get pregnant a second time when you're already pregnant. Plus: When did we start calling citizens consumers?Learn more about advertising on the HowStuffWorks podcasts at www.howstuffworks.com/advertisers.htmAnd to learn about your ad choices when listening to podcasts, visit https://www.howstuffworks.com/privacy.htm#ad-choices