| Current Zoology(formerly Acta Zoologica Sinica), Feb. 2002, 48(1): 1 - 19 |
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| Title: | DIGESTIVE STRATEGIES OF MAMMALS |
| Authors: | Ian D. Hume |
| Abstract: | Understanding an animal[DK1]'s nutritional niche is fundamental to a full appreciation of its ecology, and is important for both pest control and species conservation purposes. Carnivores have digestive systems dominated by the small intestine, which can be related to the generally high digestibility of their food. Omnivores have more complex gastrointestinal tracts, with a hindgut caecum in which some microbial fermentation takes place, and they have longer mean retention times (MRTs) of digesta. The longest MRTs are found in herbivores, in which digesta are retained and fermented by dense microbial populations in one or more regions of relative stasis. However, not all herbivores have digestive systems that maximise fibre digestibility; only ruminants, camelids and very large hindgut fermenters (rhinos, elephants) achieve this. Instead, many other herbivores (foregut fermenters such as kangaroos and small hindgut fermenters such as rabbits, voles and possums) have digestive systems that sacrifice maximal fibre digestibility for a capacity to process large amounts of forage, even when forage fibre content becomes very high. These different digestive strategies result in the wide range of nutritional niches found among mammals. |
| Keywords: | Carnivore, Herbivore, Omnivore, Caecum fermenter, Colon fermenter, Foregut fermenter,Mean retention time, Digestive strategies |
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