Facts About Animals Digestive System

The digestive systems of animals are as varied as the food they eat. The best way to understand how animals use their food, however, is to approach the subject from the broad types of  diets they consume. Meat eaters face different challenges than plant eaters, and their digestive systems reflect these differences.

Herbivores: Ruminants and Hind Gut Fermenters

Herbivores depend on plant material as a food source. Because this material is tough and fibrous, it is difficult for their bodies to convert it to a usable form.  he digestive systems of these animals handle this challenge by breaking down the plant material through the process of fermentation. Cows, goats, deer, sheep and other ruminants have complex four compartment stomachs that are well suited to the fermentation of grasses and other plants. Additionally, they regurgitate and re-chew much of their food after initial breakdown. This process of "chewing the cud," further breaks down plant material for effective fermentation. In hind gut fermenters, such as horses, rabbits, porcupines, guinea pigs and others, fermentation is also essential for the breakdown of plant based diets. In these animals, however, fermentation occurs later in digestion after food has passed the glandular stomach, and they do not regurgitate and re-chew their food. 

Carnivores and Omnivores

Carnivores and omnivores have simpler digestive systems than herbivores. Animal flesh, unlike plant material, is relatively easy to use, so these animals do not need the complex digestive machinery of herbivores. True carnivores, including cats, some birds, many fish and aquatic mammals, have shorter intestines than herbivores or omnivoreThey also have more strict dietary requirements for certain nutrients, because their bodies cannot synthesize them. Omnivores, like dogs, raccoons, primates, pigs and others have somewhat longer intestines than carnivores, since they do need to process some plant material. While omnivores have more specific dietary requirements than pure herbivores, their bodies tend to be able to synthesize more of the needed nutrients than the bodies of obligate carnivores.