That little indent in your abdomen is throwing a party—and 1,400 different species of bacteria showed up. Scientists from North Carolina State University's Belly Button Biodiversity Project swabbed the navels of volunteers and discovered something remarkable: your belly button is basically a rainforest of microbes.

The Belly Button Biodiversity Project

Researchers collected samples from 60 volunteers and found a staggering diversity of bacterial life. While the average person hosts about 67 species in their navel, the collective pool across all participants included roughly 1,400 distinct species.

Here's where it gets weird: 2,188 species were identified in total, and most were rare—662 species appeared in only a single belly button. Your navel's bacterial community is essentially as unique as your fingerprint.

Some Unusual Discoveries

The researchers found bacteria that had no business being there:

One participant harbored bacteria previously found only in Japanese soil—despite never visiting Japan
Another hosted species typically found in ice caps and thermal vents
Some belly buttons contained bacteria associated with kimchi fermentation

Nobody can fully explain how these microbes ended up colonizing human navels thousands of miles from their natural habitats.

Why Belly Buttons?

Your navel is the perfect bacterial Airbnb. It's warm, moist, and mostly undisturbed. Most people don't scrub their belly buttons thoroughly (be honest), creating a stable environment where bacterial communities can thrive for years.

The shape matters too. Innies—which about 90% of people have—create deeper pockets that trap more bacteria, dead skin cells, sweat, and lint. This organic debris becomes a buffet for microbes.

Should You Be Worried?

Not at all. The vast majority of these bacteria are completely harmless—many are actually beneficial. Your skin's microbiome, including the belly button ecosystem, helps protect you from harmful pathogens by occupying space that dangerous bacteria might otherwise colonize.

That said, the Belly Button Biodiversity Project did find that washing frequency matters. Participants who cleaned their navels regularly had different—though not necessarily fewer—bacterial communities than those who didn't.

The Bigger Picture

The belly button study highlighted just how little we know about the human microbiome. Scientists estimate your body hosts 38 trillion bacterial cells—roughly equal to or exceeding your human cell count. Most of these microbes live in your gut, but every surface of your body supports its own microbial community.

Your belly button bacteria aren't invaders. They're residents, and they've been evolving alongside humans for millennia. That tiny, often-ignored body part is a window into the invisible ecosystem you carry everywhere you go.

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