Rob Dunn and his team of ecologists aren't your average navel gazers. They're professional navel gazers, thank you very much, and their new study details the microbial contents of 60 volunteers' belly buttons.

The upshot? Belly buttons, it turns out, are a lot like rain forests.

The whole thing started about two years ago. An undergrad's only-in-a-biology-lab idea—sampling colleague's navel bacteria for a holiday card—struck a chord with the North Carolina State University team, which had adopted a new focus on citizen science.