The digestive tract of giant pandas retains the characteristics of their ancestors, similar to carnivorous animals, such as relatively short digestive tract, sharp canine teeth, single chamber stomach, no cecum, relatively sharp claws, and more developed meat pads.
For a long time, there has been a mystery about the evolution of giant pandas: why have they evolved into such special herbivores, while their teeth and digestive tract are still carnivorous? On the surface, this seems to be a mistake. Compared with other herbivorous animals, the digestive tract of giant pandas is very short, which means that food cannot stay in the digestive tract for a long time and less nutrients are absorbed. Giant pandas will excrete feces within 5-13 hours, and food from horses or cows must remain in their bodies for 24 hours. Moreover, its internal organs lack microorganisms to help it digest the rough cellulose in its food. Most herbivorous animals can digest 80% of their food, while giant pandas consume less than 17%. In order to make up for their deficiencies in the digestive system, giant pandas have developed an ability to eat the most food in the shortest possible time. They store bamboo leaves near their mouths, accumulate a certain amount, and then eat them together. Moreover, in this rush to eat, giant pandas only choose the most nutritious part of bamboo. On the other hand, in order to save energy, giant pandas try to minimize social activities, reduce their range of activities, and shorten their pregnancy period. These can help them maintain such a large body and reduce energy loss.