Comic Strips

That article says exactly what I said about Panda's:

Despite its taxonomic classification as a carnivoran, the giant panda's diet is primarily herbivorous, with approximately 99% of its diet consisting of bamboo. However, the giant panda still has the digestive system of a carnivore, as well as carnivore-specific genes, and thus derives little energy and little protein from the consumption of bamboo. The ability to break down cellulose and lignin is very weak, and their main source of nutrients comes from starch and hemicelluloses.

While primarily herbivorous, the giant panda still retains decidedly ursine teeth and will eat meat, fish, and eggs when available. In captivity, zoos typically maintain the giant panda's bamboo diet, though some will provide specially formulated biscuits or other dietary supplements.

They have developed some minor digestive traits that help them process bamboo, but they don't have the four chambered stomach of a cow or the extra-long hindgut of a gorilla to thoroughly digest plant matter. They have to seasonal migrate to get the amount of nutrients they need from young bamboo shoots and mature bamboo leaves. Their bodies could easily process a carnivorous diet, but their metabolism has become too slow for then to manage to hunt almost anything besides plants.