||Human Homo sapiens
||Sender R, Fuchs S, Milo R. Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLoS Biol. 2016 Aug 19 14(8):e1002533. doi: 10.1371/journal.pbio.1002533. p.4 box 1 bottom paragraphPubMed ID27541692
|| Cummings JH, Bingham SA, Eastwood MA, Heaton KW. Fecal Weight, Colon Cancer Risk, and Dietary Intake of Nonstarch Polysaccharides (Dietary Fiber). Gastroenterology 1992 103:1783–9.  Southwell BR, Clarke MCC, Sutcliffe J, Hutson JM. Colonic transit studies: normal values for adults and children with comparison of radiological and scintigraphic methods. Pediatr Surg Int 2009 25:559–72. doi: 10.1007/s00383-009-2387-xPubMed ID1333426, 19488763
||Primary source  abstract: "The sitz or plastic marker study for colonic transit has been around for many years. It is applicable where an X-ray machine exists, is widely used and is accepted as the gold standard for diagnosing constipation. Recently, radiopharmaceutical methods have been developed. The theme of this review is their possible roles in the assessment of paediatric bowel motility disorders in patients presenting to paediatric surgeons."
||P.4 box 1 bottom paragraph: "[Investigators] can sanity-check this volume [of colon] estimate by looking at the volume of stool that flows
through the colon. An adult human is reported to produce on average 100–200 grams of wet stool per day [primary source 18]. The colonic transit time is negatively correlated with the daily
fecal output, and its normal values are about 25–40 hours [primary sources 18,19]. By multiplying the daily output and the colon transit time, [they] thus get a volume estimate of 150–250 mL,
which is somewhat lower than but consistent with the values above, given the uncertainties and very crude estimate that did not account for water in the colon that is absorbed