The gastrointestinal tract, also known as the gut or alimentary canal, is a tube by which bilaterian animals (including humans) transfer food to the digestion organs. In large bilaterians, the gastrointestinal tract generally also has an exit, the anus, by which the animal disposes of solid wastes. Some small bilaterians have no anus and dispose of solid wastes by other means (for example, through the mouth).