Beneath this mat, and on top of which Zimapán man was placed, was a perfectly woven sheet of native brown cotton.”The Zimapán Man was recovered in the state of Hidalgo and the locality of Zimapán. Image: Rosas-Plaza et al., 2025, PLOS One, CC-BY 4.0What is the gut microbiome? Inside all of our intestines is a bevy of bustling natural bacteria and other microorganisms working together called the gut microbiome. The gut microbiome helps our bodies digest important nutrients, train our immune system, and can even stimulate the production of important neurotransmitters in our brains. There are certain types of bacteria that are widely associated with the human gut microbiome.