Despite its taxonomic classification as a carnivoran, the giant panda's diet is primarily herbivorous, consisting almost exclusively 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 consumption of bamboo. Its ability to digest cellulose is ascribed to the microbes in its gut. The giant panda is a "highly specialized" animal with "unique adaptations", and has lived in bamboo forests for millions of years. The average giant panda eats as much as 9 to 14 kg (20 to 30 pounds) of bamboo shoots a day. Because the giant panda consumes a diet low in nutrition, it is important for it to keep its digestive tract full. The limited energy input imposed on it by its diet has affected the panda's behavior. The giant panda tends to limit its social interactions and avoids steeply sloping terrain in order to limit its energy expenditures.