According to the Smithsonian National Zoological Park, 99 percent of the giant panda’s diet is comprised of bamboo. However, they occasionally eat other grasses, rodents or deer. In captivity, pandas are given sweet potatoes, carrots, apples, sugar cane and specialized biscuits in addition to bamboo.
Pandas rely on bamboo because it is plentiful and persists throughout the year. However, as they only extract about 17 percent of the energy in the plant, which is already low in calories, they must eat constantly. In fact, giant pandas spend about 10 to 12 hours feeding each day, according to the University of Michigan, Department of Zoology. Because of these factors, giant pandas must be careful not to expend too much energy on a day-to-day basis. When the pandas are forced to travel, they often forage while doing so.
Giant pandas have a stereotypical sitting posture that they adopt while feeding on bamboo. This posture allows the pandas to use both of their front paws for feeding. To help hold the bamboo, giant pandas have evolved a pad of skin on their hands that functions like an extra digit.
To digest their food, pandas have also evolved very broad molars and muscular stomachs. Both of these adaptations enable them to cope with their tough, fibrous diet.