Digestion a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion. In some birds it is an expanded, muscular pouch near the gullet or throat. In adult doves and pigeons, the crop can produce crop milk to feed newly hatched birds. Certain insects may have a crop or enlarged esophagus. Herbivores have evolved cecums (or an abomasum in the case of ruminants). Ruminants have a fore-stomach with four chambers. These are the rumen, reticulum, omasum, and abomasum. In the first two chambers, the rumen and the reticulum, the food is mixed with saliva and
Cheek pouch face with food." When full, the pouches can make the hamsters' heads double, or even triple in size. The platypus feeds on annelid worms, insect larvae, freshwater shrimps, and yabbies (freshwater crayfish) that it digs out of the riverbed with its snout or catches while swimming. It uses its cheek-pouches to carry prey to the surface for eating. The cheek pouch is a specific morphological feature that is evident in particular subgroups of rodents (i.e. Heteromyidae and Geomyidae (or Gopher)), yet a common misconception is that certain families, like Muridae (including the common black and brown rats), contain this structure