Explain digestive adaptations in ruminant herbivores

Ruminant herbivores (such as cows, goats, and deer) have evolved a complex, four-chambered stomach — rumen, reticulum, omasum, and abomasum — to digest cellulose-rich plant food efficiently.

• In the rumen, food is partially digested by symbiotic bacteria and protozoa.
• The cud (partially digested food) is regurgitated back into the mouth, chewed again, and swallowed — a process called rumination.
• In the omasum, excess water is absorbed, and in the abomasum, gastric juices complete digestion.

This multistep process allows ruminants to extract nutrients and energy from fibrous plant material that non-ruminant animals cannot digest easily.