They rely little if at all on their stomachs for complete fiber digestion. Omnivores and Carnivores also have simple stomachs, similar to those seen in hindgut fermenters. A cecum can be absent or present in mammals. It is generally present in herbivores and omnivores, and functions as a holding area for food material that requires long-term microbial breakdown. The cecum is sometimes absent in carnivores Many mammals possess a sacculated large intestine.
Mammals possess well developed, highly efficient kidneys.
They also have separate excretion of feces and urine, thus the cloaca is absent. It really deserves its own section due to its importance in digestion in higher organisms, its complicated secretion patterns, and its involvement with intestinal pathogens which can have very significant impacts on nutritional needs. The SI is similar in design across most higher species 2. It is almost always the longest part of alimentary tract. Diseases that affect this organ tend to have a greater impact on nutrient absorption compared to other organs of the GI tract.