Read the full story from NPR.
Like the human gut, the belly of every bovine contains a microbial engine — engines, really — since cows have four-part stomachs. Those unicellular inhabitants do most of the digestive acrobatics of processing a cow’s gnarly, fibrous diet of grains, hay, and grass. They’re also responsible for some of the cattle industry’s greenhouse gas contributions, since, as it turns out, cows don’t make methane. Bacteria make methane.