A Comparative-Study of Macroscopic and Microscopic Dimensions of the Intestine in 5 Macropods (Marsupialia, Macropodidae) .2. Relationship With Feeding-Habits and Fiber Content of the Diet

Abstract

A comparative study of macroscopic and microscopic dimensions of the intestines in five macropod species indicated that the grazing macropods (the red kangaroo, Macropus rufus, and the eastern grey kangaroo, Macropus giganteus) had significantly longer caeca and large intestines than those of the browsing macropods (the swamp wallaby, Wallabia bicolor, and the red-necked pademelon, Thylogale thetis). This trend was not observed in the small intestine. The arid-adapted M. rufus also had a significantly longer large intestine than M. giganteus, which may be a water-conservation feature. Intestinal villi were tall in T. thetis, which consumed a less fibrous diet, whereas the agile wallaby, Macropus agilis, on a highly fibrous diet, had short villi; other macropods, on diets of medium fibre content, had villi of intermediate height. Thus, the size of the hindgut (i.e. caecum and large intestine) may provide an index of the specific feeding habit of a species (browsing or grazing), whilst parameters of the villi of the small intestine may reflect the quality of the animals' current diet.