On the basis study of 4 giant pandas, the average ratio of intestine length to body length is 5.85, placing the giant panda plumb in the middle of the carnivore range; It has villi measuring 1000 (p)m or more, which is much longer than the herbivores like cow and goat. The giant panda does not have long intestine, nor any cellulose-digesting symbiotic microorganisms to help it digesting the food, like the herbivore does. Not only that, it choose the most difficult plant -- bamboo to feed on. So there must be some evolutionary adaptations in their alimentary canal which are designed specifically to cope with their highly specialised diet.
Although the alimentary canal is short, the gullet of the giant panda is far tougher than that of most other mammals. This affords it some protection from the hard splinters of woody debris from bamboo stems. The wall of a giant pandas stomach is very thick, almost gizzard-like, due in part its extreme muscular development, and itself an adaptation for squeezing and churning the roughly chewed bamboo fragments. The stomach and digestive tract have numerous mucous cells, the copious production of mucus helps to guard against the cutting or tearing of the gut wall. Indeed, fresh panda droppings were still coated with a layer of mucus.