The majority of these bacteria and microbes reside in your gut, which is why you may have heard of the term ‘gut health’. But beyond your gastrointestinal tract, you also have communities of vastly different species in your nose, your groin, and on your skin, etc. Some microbes prefer to live on the cool, dry skin of your knee. Others gravitate towards the warm, wet darkness of your mouth. They are tiny ecosystems as different from each other as the rainforest and the desert. Wherever they live, they’ve evolved to thrive there.