It’s just 15 inches south of your chin, and you can touch it while whistling and standing on one leg. But how well do you really know your belly button?

A paper published last week in the research journal PLOS One suggests just how alien an environment it might be. Scientists and citizen explorers working on the Belly Button Diversity Project, one of many projects run by Your Wild Life, an ongoing enterprise “exploring the ecological frontiers that exist right under our noses,” analyzed swabs from 66 people’s navels and found 2368 different bacteria species.