Hindgut versus Foregut Fermenters

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.

13 thoughts on “Hindgut versus Foregut Fermenters”

u wot m8? March 18, 2014 at 7:07 pm

they eat the poo poo

Veronica June 11, 2015 at 1:43 am

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

Amanda October 20, 2015 at 6:23 pm

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.

jaman November 16, 2016 at 7:44 am

Horses are consider hindgut fermenters because they ferment their food in the large intestine. Cellulose digesting bacteria cant live in the horse stomach because its glandular, bacterias will die. Instead cecum is the perfect home for bacterias. thats why they are called hindgut fermenters and horses cant also regurgitate because they have this large one way cardiac sphincter that disables them to vomit.