Trillions of tiny organisms—microbes—are all over, and inside, each of our bodies. They’re on our skin and genitals, and in our mouths, ears and sinuses. By far the majority of them, though, camp out in our gut. Estimates are that there are between 30 trillion and 400 trillion microorganisms in the human gut, and from three to 100 times more bacteria in the gut than there are cells in the human body.
Assuming that there are inly 30 trillion or so organisms in our gut, and ignoring the Mitochondria in each cell, and not worrying about bacteria in the mouth, and on the skin, there are roughly 4000 times more cells in a human body than on the earth.
If we equate a human body to a galaxy, we would need to know about 4000 humanoid inhabited worlds in this galaxy to be even considered to be in the same league as successful as bacteria.
Moreover, we know that gut bacteria have a hot line to the human brain. In other words, bacteria indirectly control their environment at the galaxy scale.
So, while humans are pretty successful in their 1/8 inch of their large intestine, they got some doin to do to match gut microbes.