I think in humans burps are a release of swallowed air, while farts are gasses produced by fermentation in the intestines. Ruminants OTOH have a fermentation ch

I think in humans burps are a release of swallowed air, while farts are gasses produced by fermentation in the intestines. Ruminants OTOH have a fermentation chamber (rumen) as the first part of their digestive system (their first 'stomach'). Other animals have different fermentation strategies.