Hindgut versus Foregut Fermenters

hidgut vs foregut

Horses are hindgut fermenters, while sheep are foregut fermenters.

Obtaining and transporting nutrients is a vital function for all multicellular organisms and different species have evolved some interesting ways of gaining, storing and digesting their nutrients. Amongst herbivores, for example, almost all have cellulose digesting bacteria within their gut that live symbiotically, assisting with the break down of vegetation. Some are classified as “hindgut fermenters”, which have microbes and fermentation in their hindgut, the caecum and proximal colon. These animals are less effecient at digesting their food and can sometimes be observed practising coprophagy (eating faeces).

  • Horses
  • Koalas
  • Wombats
  • Possums
  • Pigs
  • Rabbits
  • Rats

Other herbivores are “foregut fermenters”, or ruminants, which have pouches with microbes in the stomach. These microbes consume glucose from cellulose but produce fatty acids that the animal can use for energy. Microbes can also be digested further along the digestive tract as they are also a source of protein. Forgut fermentation, or rumination, is a slower digestive process, but has the advantage of providing more nutrients and wasting less energy. Foregut fermenters include:

  • Sheep
  • Cattle
  • Hippopotumus
  • Kangaroos and Wallabies

Good information about different types of digestive systems from a UK Veterinary site, Comparative Digestion.

3 thoughts on “Hindgut versus Foregut Fermenters

  1. Veronica

    On your list of Hindgut animals you have:
    1. Pigs
    2. Rats
    These animals are not handgun they are mono gastric.

  2. Amanda

    Actually, Veronica, pigs and rats are not handguns, either. They are, however, hindgut fermenters. You’re correct in that they are also monogastric, but that does not preclude them from being hindgut fermenters. Rabbits are also monogastric and also hindgut fermenters. “monogastric” refers to having a single, glandular stomach much like a human or a dog or a cat. Hindgut fermenters are monogastric, but because they are herbivores, they need some way of using plant fiber (cellulose) as an energy source. For this reason they have very well developed cecae (singular cecum) where this fermentation occurs in order to digest cellulose and use it as energy. Because the cecum is located at the junction of the small and large intestine (near the end of the digestive tract) we say that these animals perform fermentation in the “hind gut”. Carnivores and omnivores don’t use cellulose as an energy source, so they have no area of the digestive tract devoted to fermentation.

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