It would be absolutely fascinating to learn about the neanderthal’s normal flora (I refuse to use the term “microbiome”, just for the record). We modern humans may think that our hygiene practices somehow rid our body of dangerous bugs, but the reality is that there are many species that humans constantly carry around, and they can cause many different types of infections, including ear infections. Just as one example, about 1-5% of people are natural asymptomatic carriers of S. aureus (i.e. “staph”). For that matter, it would be interesting to find out what H. sapiens were carrying around during that same time period. It could be possible that interaction with anatomically modern humans passed on a new bug that impacted neanderthal populations. In modern times, we have seen how indigenous populations were wiped out by infections introduced by western explorers.