As very selective eaters, giant pandas are herbivores that have no natural predators other than humans. According to the University of Michigan's Animal Diversity Web, bamboo makes up 99 percent of the diet of giant pandas in the wild.
Giant pandas have a number of different adaptations that help them to fill their niche as bamboo-eating herbivores. Some of these adaptations are behavioral. For example, giant pandas spend most of their traveling time eating. Additionally, giant pandas have an extra digit on their front paws which helps them to hold the bamboo. Bamboo is very low in nutritional value, and so the bears must consume great quantities of it to nourish their large bodies.