SELECTIVE RETENTION OF FLUID DIGESTA IN THE HINDGUT BANDICOOTS AND OTHER MARSUPIAL CECUM FERMENTERS

Many small hindgut fermenters have a mechanism in the proximal colon t hat separates fluid and/or bacteria from large particles, and excretes the large particles relatively rapidly. The fluid and/or bacteria are retained in the caecum, which concentrates digestive effort in that r egion of the hind-gut and improves overall digestive efficiency. Previ ously observed among marsupials only in arboreal marsupials, selective retention of fluid digesta has recently been reported also in bandico ots, small terrestrial omnivores. The separation mechanism operated in dependently of the nature of the diet, indicating that it is probably an important factor in the ability of bandicoots to switch between ins ect and plant foods, and thus to exploit nutritionally unpredictable e nvironments. Results are discussed in relation to possible locations i n the marsupial hindgut of the pacemaker that in eutherians has been s hown to initiate retrograde movement of fluid and small particles in t he proximal colon towards the caecum.