Based on information from the Smithsonian Institution, pandas eat primarily bamboo. In fact, in the wild, 99 percent of a panda's diet consists of bamboo. Of course, pandas also eat some other foods.
Pandas, which typically live in coniferous forests, do primarily eat bamboo, but may supplement their diet with foods such as grasses and the occasional small rodent or musk deer fawn. However, pandas who are kept in the zoo instead of the wild have a bit of a different diet. Pandas in zoos have a diet that usually consists of bamboo, carrots, apples, sugar cane and sweet potatoes.