chew cud

chew the/(one's) cud

To contemplate something. ("Cud" is partially digested food that is regurgitated to be chewed again, a common behavior of cows.) I've been chewing my cud for days, but I still haven't decided whether I'm taking the job or not. Sometimes you just need to stop chewing the cud and make a decision.
See also: chew, cud
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

chew one's cud

Fig. to think deeply; to be deeply involved in private thought. (Alludes to the cow's habit of bringing food back from the first stomach into the mouth to chew it, called chewing the cud.) He's chewing his cud about what to do next.
See also: chew, cud
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
These many ruminants also release methane gas into the atmosphere when they chew cud, adding to the pile of greenhouse gases that cause global warming.
They are investigating how enzymes found in the stomachs of cattle and other ruminants, animals which "chew cud", could be used industrially to break down the tough structures of plant and tree matter.
"While humans may have longer intestines than animal carnivores, they are not as long as herbivores'; nor do we possess multiple stomachs like many herbivores, nor do we chew cud," the magazine adds.
class="MsoNormalCxSpMiddleIf only the human stomach could consume a lot of food in one sitting so that we can then chew cud throughout the rest of the day like a ruminant!