How is a cow like a cockroach?

The methane gas emanating from sewage treatment plants, landfills, and the muck submerged in swamps comes mainly from methane-producing Archean  These so-called methanogens interact with bacteria in a way that allows both to thrive and keep ecosystems running.

Methanogens sustain cattle, goats, sheep, deer, elephants, and all other ruminants plus cockroaches, termites, beetles, and millipedes—thousands of arthropod species in all. Their digestive tracts contain a heterogeneous mixture of microbes from the three domains of living things: Archean  Bacteria, and Eukarya. The bacteria and Archean cling to the rumen wall and to feed stuffs entering the rumen while protozoa tend to stay in the liquid.

A cow’s four-part digestive organ—rumen, reticulum, omasum, and abomasums—evolved for fermentation. Ruminant animals scarcely chew their food after yanking it from soil; they masticate just enough to mix the grasses with saliva, and then send the bolus into the esophagus leading to the rumen. The cow rumen holds up to 20 gallons, the interior resembling a perpetual washing machine lined with small protuberances called papillae. These structures increase the rumen’s inner surface area to make absorption more efficient and to increase attachment sites for microbes. Rumen fluid ranges from Kelly green from grass diets to olive-green when the cow gets mainly a hay diet. Every minute or so the esophagus launches a bolus into the mix like a trope....