Chewing chewing, the food (now called a bolus) is swallowed. It enters the esophagus and via peristalsis continues on to the stomach, where the next step of digestion occurs. Premastication is sometimes performed by human parents for infants who are unable to do so for themselves. The food is masticated in the mouth of the parent into a bolus and then transferred to the infant for consumption. (Some other animals also premasticate.) Cattle and some other animals, called ruminants, chew food more than once to extract more nutrients. After the first round of chewing, this food is called cud. Chewing is
Kosher animals that naturally live in Canaan, except for primates, and equids (horses, zebras, etc.), which are not mentioned in Leviticus as being either ritually clean or unclean, despite their importance in warfare and society, and their mention elsewhere in Leviticus. In an attempt to help identify animals of ambiguous appearance, the Talmud, in a similar manner to Aristotle's earlier "Historia Animalium", argued that animals without upper teeth would always chew the cud and have split hoofs (thus being ritually clean), and that no animal with upper teeth would do so; the Talmud makes an exception for the case of the camel