Both seeds and fruits provide a far more nutritious diet than leaves. Many of the 1750 species of rodents in the world live mostly or entirely on seeds. A number of the mammals mentioned above will eat flowers when given the opportunity as well as bark. Also included in the diets of many herbivores, as well as many omnivores, are fungi. Finally, several genera of tropical bats feed almost exclusively on nectar and pollen which they extract from flowers with specially evolved tongues.
Ruminants chew their food more than once.
It is brought up from the rumen to the mouth after a certain amount of fermentation. From there it moves on through the digestive system. Digestion is completed in the fourth stomach and nutrients are extracted in the small intestine. In both ruminants and non-ruminants some additional fermentation occurs in the caecum. A number of the Carnivora are omnivores though, particularly the Bears, Badgers and Mongooses.