Jane Clay Adkisson, aged 7, of Clover, Va., for her question:

Why does a cow need to chew the cud?

Our cows in a safe and quiet field do not really need to chew the cud. But their distant ancestors did. They were wild creatures who fed upon grass and other green stuff. And their world was full of wild beasts who liked to feed on the gentle grass eaters.

The wild cattle could not spend hours grazing in the open fields. The hungry tigers and other beasts could spot them too easily.  So the cattle had to snatch a meal quickly. They grabbed bunches of grass and swallowed it without chewing.

Later they found a safe place, probably hidden in the thickets. They coughed up the swallowed grass, a mouthful at ‑a time. This time they chewed it carefully and swallowed it again. The chewed food then went to the stomach to be properly digested. These wild cattle had special stomachs. One section held the cud, or unchewed food. Another section did the real digesting.

Our cattle need not eat and run. They can feed without fear of being pounced upon. But they still keep their old cud‑chewing habits.