The Four Stomachs Whitetails, like most herbivores, are ruminants. As ruminants, deer can use many foods indigestible to humans and other nonruminants. This process is especially important for animals living on low-quality forage. This largest stomach compartment lies on top of the intestines. It functions both as a storage and fermentation chamber.
Food is mixed with bacteria and protozoa, which aid the digestive process.
When a deer feeds, it quickly fills its rumen. Later, it regurgitates the food and chews it more thoroughly. Rechewing helps digestion and allows microbes to break down cellulose and other plant fibers into easily digested materials. It forces water into the rumen, suspending food particles and floating them to the reticulum where the digeston continues. Similar processes occur in the rumen and reticulum, but most material in the reticulum consists of smaller particles.