A member of the order Carnivora, Giant Pandas have evolved to specialize on a diet of bamboo. Bamboo is a poor food source, low in protein and high in lignin and cellulose, and wild Giant Pandas can only digest an average of 17% of dry matter and about 27% of hemi-cellulose. Thus, to meet their daily energy requirement, Giant Pandas must consume a large amount of bamboo, up to 12.5 kg per day, and defecate more than 100 times daily. Pandas have large, muscular jaws with skeletal features to accommodate the musculature and its famous “pseudothumb” used to hold and manipulate bamboo for processing. However, compared with other herbivores, the Panda has very low digestive efficiency because its digestive tract still resembles that of its carnivorous ancestors. The Panda’s feeding strategy emphasizes volume, requiring it to allocate much of its time to foraging (approximately 14 hours daily).
Giant Pandas also compensate for digestive inefficiency by selecting the most nutritious parts of bamboo plants and by altering diet selection seasonally commensurate with changes in nutritional profiles of bamboo species. They demonstrate strong preference for seasonally available new bamboo shoots, rich in nutrition and energy and low in fibre. Outside the late spring bamboo shoot season, Pandas favor leaves, although more stems are incorporated into their diet during the winter months when leaf quality and quantity diminishes.
Habitat and Movement Pattern
Using various measures of habitat suitability, efforts to map Panda habitat have proven valuable for guiding the establishment of the Panda reserve system. Giant Pandas typically occupy temperate montane forests at altitudes of 1,500–3,000 m. Range-wide analysis of ecological covariates associated with Panda presence suggested that Giant Pandas are associated with old growth forests, a finding previously unrecognized in studies implemented on smaller spatial scales. As an obligate bamboo specialist, the Giant Panda’s reliance on this resource is clear, yet it has usually been ignored in habitat suitability models because mapping bamboo understory using remote sensing techniques is difficult. Including understory bamboo in habitat models dramatically decreases estimates of available habitat and increases measures of fragmentation.
Giant Pandas are a solitary and seasonal-breeding mammal, only coming together during the breeding season, from March to May, for reproductive purposes. Male Pandas occupy large home ranges overlapping several females and are known to congregate around estrous females. Male Pandas are able to locate females across large areas, and demonstrate fierce and injurious aggression in competition for access to females. Because Pandas live a solitary existence, they must rely heavily on "chemosignals" to communicate with one another without necessitating face-to-face encounters. Giant Pandas make use of a system of traditional communal scent mark stations that provide them with reliable locations they can visit to deposit signals and investigate signals left by other Pandas.