Scavengers and carnivores have significantly higher stomach acidities (lower pH) compared to herbivores or carnivores feeding on phylogenetically distant prey.

“their hypothesis was that species feeding on either carrion or organisms that are close phylogenetic relatives should require the most restrictive filter measured as a highly acidic stomach or a high stomach acidity i don't love their verbiage here a high stomach acidity means a very acidic stomach i believe earlier i said they were distant phylogenetic relatives i misspoke they are saying these are close phylogenetic relatives and they are feeding on carrion or organisms that are close phylogenetic relatives they want to protect themselves from foreign microbes conversely their hypothesis is that species feeding on a lower trophic level or food that is distantly related to them herbivores should require the least restrictive filter as the risk of pathogen exposure is lower”

“what has been found consistently is that the ph of the stomach meaning the amount of acid in the stomach with a lower ph indicative of more acidic or more protons in the concentration is associated with phylogenetically distant foods meaning they are more likely to um eat foods that are distant than them and that are likely to be rotting and this is something we see across species and it's a pretty good indicator that human stomachs are very acidic on the order of 1 to 1.5 likely due to the fact that our first foods were carry-on were not carry-on in the airplane but carrion c-a-r-r-i-o-n meaning rotting animal flesh”