A ruminant has a ____ compartment stomach.

• A. 4
• B. 3
• C. 2
• D. 5

Answer: (A)

Ruminants have a four-chamber stomach to allow extensive microbial fermentation of fibrous plant material before digestion. The first two chambers, the rumen and reticulum, act as large fermentation vats where microbes break down cellulose and produce energy-rich compounds; cud chewing enables further breakdown and better digestion. Ingesta then move to the omasum, which concentrates and absorbs water and shortens particles, and finally to the abomasum, the true stomach where acid and enzymes digest proteins. Because this foregut fermentation system is four-chambered, the correct count is four. (Some other animals, like camelids, have a three-chamber stomach, but that’s not a ruminant.)