We've got two stories this week. The first is about why we run, not just as runners but as human beings. In the 1980s a biologist named Dave Carrier came up with a controversial theory about human evolution. He called it the "Running Hypothesis" and it was based on the idea that humans became elite long distance runners so that we could hunt large game by chasing it on foot until the animal collapsed from exhaustion. So Carrier and his brother, a radio producer named Scott went to Wyoming to prove this theory by trying to run down an antelope until it collapsed. The second story comes from producer Karen Given and is about a runner who set a surprising marathon goal after volunteering for a major surgery to save his mother-in-law’s life. We also learn how to hide an engagement ring in your running clothes. Additional Listening:Producer Scott Carrier has a podcast called Home of the Brave. You can listen to more of his work at homebrave.com.Producer Karen Given works on a show called Only A Game. You can listen to more of her work for that show at http://www.wbur.org/staff/karen-given.

This episode of Human Race is sponsored by Aaptiv, an on-demand audio fitness app that you can do at home, at the gym, outdoors - anywhere. Get your first month free when you sign up for a monthly subscription at and use the promo code "HUMAN."Episode Credits: Host: David WeinbergProducers: Scott Carrier, Karen Given Theme music: Danny Cocke Human Race editor in chief: David Willey Human Race is a proud part of Panoply.Follow us on Twitter (@rwaudio) and Facebook (Runner's World Audio).Learn more about your ad choices. Visit podcastchoices.com/adchoices