What is the origin of ruminate?

Ruminate, “to meditate, muse, or ponder,” comes from Latin rūminātus, the past participle of rūmināre, rūminārī “(of cattle) to chew the cud; (of humans) to turn over in the mind, ponder” (Roman cattle were famous throughout the ancient Mediterranean for their contemplativeness). Rūmināre is a derivative of the noun rūmen (inflectional stem rūmin) “throat, gullet.” Rūmen is possibly related to Sanskrit romantha– “cud-chewing” and Welsh rhumen “belly, paunch, udder.” Ruminate entered English in the first half of the 16th century.