Mary Roach
Science Journalist and Author

The Secret Life of Bacteria

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On a day-to-day life in the colon is probably pretty mundane, says science writer Mary Roach.

Mary Roach

Mary Roach is an American science writer. She has published three books: Stiff: The Curious Lives of Human Cadavers (2003), Spook: Science Tackles the Afterlife (2005) and Bonk: The Curious Coupling of Science and Sex (2008). Raised in Etna, New Hampshire, she holds a bachelor's degree in psychology from Wesleyan University and currently resides in San Francisco, California.

She began her writing career at the San Francisco Zoological Society, producing press releases on such topics as elephant wart surgery.[1] In 1986, she sold a humor piece about the IRS to the San Francisco Chronicle. That led to a spate of humorous first-person essays for such publications as Sports Illustrated, Vogue, The New York Times Magazine, Discover, Outside, Reader's Digest (for whom she wrote a monthly humor column) and GQ.

She appeared on The Colbert Report, a satirical news program, in November 2005.



Mary Roach: A day in the life of the bacteria in your gut.  They are on a different schedule from you because you’re eating and it’s taking a certain amount of time for the bacteria to make their way.  The bacteria are all in the large intestine which is the end of the line.  Well, the rectum is the end of the line.  But this is a place where your body’s kind of done with everything. You’ve absorbed – in the small intestine you’ve absorbed all the nutrients that you can that your body’s going to use.  And the stuff that they don’t want it’s the kind of stuff that you throw into the compost.  The large intestine – that’s the composter.  That’s where the bacteria live and they can use it.  And they’re like, “Oh, I’ll take that.”

So all your bacteria are down there and in your colon and they’re waiting for you to be done with what you’re gonna do with it.  And then it’s passed along so it’s a certain amount of, you know, it’s like five hours before you’re sort of – it’s making its way.  And coincidentally – that’s the peak in flatulence is about five hours after a meal when the bacteria are kind of doing their thing.  Because flatulence is gas produced by bacteria breaking down – it’s usually sugars of some kind with lentils and beans being the most famous contributors.

Anyway, so they are happily doing their thing.  So they’re on a lag from your schedule so whenever you’re eating then you sort of wait a while and then they’re eating.  And I don’t know exactly what else they do with their lives in there.  I don’t know how they pass the time in between.  I don’t know how much fighting is going on.  I think it seems to be like a lot of gang tribe warfare going on because, you know, when you hear about a fecal bacteria this is – if you were a gut bacteria and suddenly here comes this whole – it’s this, you know, population – giant population of foreigners.  You know, it’s like some crazy immigration situation where they’re duking it out and the strongest ones win.  So that’s a whole global warfare scene going on.

On a day-to-day life in the colon is probably pretty mundane.  It’s very centered around food, a little bit of, you know, reproduction.  Yeah, it’s a simple life I think.  Pleasant.  Probably pleasant.  The weather is great.  It’s very uniform.  It’s kind of like – kind of like the Bahamas in there.  It’s very – minus the tropical breezes I guess.  Oh no, a little bit of the breezes.

Directed / Produced by Jonathan Fowler and Elizabeth Rodd