The primary food of giant pandas is bamboo. Though they belong to the order Carnivora, giant pandas have evolved to primarily consume bamboo, which makes up about 99% of their diet. They require a large quantity of this plant—up to 40 pounds per day—to meet their nutritional needs, as bamboo is low in calories. Pandas eat various species of bamboo, depending on the season and availability, and their unique digestive system is fairly inefficient at processing the fibrous material. Consequently, they spend a significant portion of their day feeding to sustain their energy levels and remain healthy.