The ruminant and the non-ruminant digestive systems are very different. The one major difference between the two are their structure and function of the stomach. The non-ruminant, also called the monogastric, has a very simple digestive system. That is also where it gets the name monogastric from; their single compartment! On the other hand, the ruminant digestive system has four compartments. They consist of the rumen, reticulum, omasum, and abomasum. While the monogastric digestive system works very simply, the ruminant has a very complex process. Animals with the ruminant digestive system use most of their time chewing their food, swallowing it, and regurgitating it. They repeat this process until the food is ready for digesting. Animals with the monogastric digestive system have enzymes in their saliva that help break down food for them. Ruminants don't have this enzyme and that's the reason why they have to go through this long process to digest their food.