Certain symbiotic microorganisms normally occur in the cecum of the human body. The cecum is a pouch-like portion at the beginning of the large intestine where these microorganisms reside and help in the fermentation and digestion of plant materials, breaking down fibers that human enzymes cannot digest
. More broadly, symbiotic microorganisms can live in or on various plant or animal tissues, including inside root nodules of legumes (rhizobia bacteria), in the digestive tracts of animals, on skin surfaces, or near hydrothermal vents depending on the host organism and environment
. However, in humans specifically, the cecum is a primary site for such symbiotic microbial communities.
