In herbivores , the crushing force of the masseters is relatively more important. The jaw joint is generally well above the plane of tooth occlusion , allowing extra room for masseteric attachment on the dentary. Cats will strip bones clean but will not crush them to get the marrow inside. In addition to their stomach, ruminants have three large stomach-like pouches within the esophagus. This matter is then returned to the mouth in the form of a cud for further chewing, later swallowing, and more complete digestion in the other esophagal pouches and the true stomach.
Ruminants lack upper incisors and generally upper canines as well.
The lower incisors and a small incisorized lower canine crop vegetation by striking a hard keratin pad in the upper jaw. In typical mammalian molars , the enamel is restricted to a thin layer on the outside of the tooth. Pigs are examples of nonruminant artiodactyls, in which the canines are retained but splayed to the side for defense. Pig molars, like those of other omnivores such as bears and humans, contain broad, blunt cusps and basins, with enamel restricted to the outer surface. In horses , which are grazers, all incisors are retained, and a canine is retained in males.