Otzi the Iceman’s gut remains a living ecosystem

Five millennia after an arrow strike ended his life in the Italian Alps, the body of Otzi the Iceman continues to host a thriving biological community. Researchers have discovered that prehistoric bacteria and cold-adapted yeast within the mummy are not merely preserved, but are metabolically active and evolving.

A study published in the journal Microbiome reveals that the deep-freeze environment at the Eurac Research Institute has failed to halt the development of these ancient microorganisms. Lead researcher Mohamed Sarhan identified a hidden ecosystem within the mummy’s tissues that appears to be adapting to its surroundings. Among the findings, investigators noted that the gut bacteria correlate precisely with Otzi’s final high-fat meal of wild meat and ancient grains.

More unexpectedly, the research team documented the presence of Romboutsia hominis and Clostridium moniliforme—species that have largely disappeared from modern urban populations but persist in isolated tribal societies. Even more striking is the resilience of certain yeast populations, which have expanded over the last nine years by consuming the phenol disinfectants intended to preserve the remains. This microbial activity challenges current museum protocols, raising concerns that standard sterilization chemicals may inadvertently support, rather than eliminate, biological threats to ancient artifacts.