Did you know that, unlike humans and most other animals, cows have FOUR stomachs? This helps them digest all of that grass that they spend all day munching on.

Cows are a type of animal that is known as a ruminant. Ruminants are even-toed hoofed mammals that eat plants. They include sheep, deer and camels. They have more than one stomach (most ruminants have four), and they chew cud. Actually, the stomachs are more like different parts, or chambers, of one large stomach system. Cows have four of these chambers. They are called the rumen, the reticulum, the omasum and the abomasum.

The rumen is the first "stomach." It's where the large amounts of plants and feed the cattle eat are stored and mushed up. In the rumen live billions and billions of microscopic organisms, such as bacteria and protozoa, that are harmless to the animal and help it digest the food and stay healthy.

Once the food goes through the rumen, the cow regurgitates it as cud. "Regurgitate" (ree-GUR-jih-tayt) is a fancy way of saying the mushed-up food goes back up to the cow's mouth, kind of like "throwing up." This may sound yucky, but it's what cows DO. The cow then chews this cud and swallows it down into the other chambers.

The reticulum is a honeycombed stomach that acts as a trap for rocks, nails or other foreign objects that cows could swallow during their day out in the field. The omasum has folds that look like book pages and act as filters for the digesting food. The last compartment, the abomasum, is like a person's stomach, in that it produces acid and enzymes to break down and digest the food.