Who gives a shit!...

[htuttle]

10. Perhaps this is a simple question, but where do the gut bacteria come from?

I'm suddenly curious about something that I just realized that I don't know. How do we all end up with the same strains of bacteria in our guts?

I can see how a symbiotic relationship might build up between a multicellular species and bacteria. But how do those particular strains of bacteria get into our guts after we're each born? Are they plentiful in the natural environment, or does it require a human-inhabited local environment to create a stock of the little wrigglies to jump into our guts?

ON EDIT:
Just found the answer:
http://en.wikipedia.org/wiki/Gut_flora#Acquisition_of_gut_flora_in_human_infants