Quick: If you checked right now, what would you find inside your belly button? If you said dirt and sweat – and maybe a little lint - you’d be right. But you’d also find a surprising amount of bacteria.

In a study called the Belly Button Biodiversity Study, researchers tested the navels of hundreds of volunteers. The result? The average belly button contains 67 different species of bacteria. Including a common type of staph, one that actually helps protect the body. Researchers also found the bacteria that makes feet smell stinky and a bacteria found deep in the navel that can survive without oxygen.

But, why study belly button bacteria? Researchers say our “belly button habitats” are filled with organisms that scientists don't know much about. As one scientist put it: “We know more about the creatures that live in the Australian outback than the ones that live in our own belly button!” That’s because our belly buttons are less exposed than the rest of our body.  They also get washed less often than the rest of our skin, so the bacteria tends to grow undisturbed. 

And if scientists can learn more about the types of bacteria we carry around, they’ll know a lot more about which bacteria are good for our skin and which are bad, how bacteria impacts our immune system and how to better treat skin diseases.

Biodiversity researchers are currently recruiting people for other studies – like one they’re doing on underarm bacteria. If you’re interested in participating, check out the website YourWildlife.org/projects.