Physical Description

A complete physical description of the Giant Panda can be found in George Schaller's 1985 book The Giant Pandas of Wolong. In it, Schaller offers this general description of the panda's appearance:

The panda is bearlike with a stocky, relatively short, barrel-shaped body, about 160-180 cm in total length. Its legs are stout and powerful, the forelegs more so than the hindlegs, and the feet are plantigrade; it walks with its toes turned in… The color pattern of the panda's pelage is unique among mammals: a white face with oval, black eye patches, and erect ears, 9-10 cm long, placed high on the head; black forelegs extending in a narrowing band over the shoulder; black hindlegs; and the rest white, except for some brownish-to-black hair on the chest… The pelage is rather course and extremely dense and wooly, though somewhat sparse on the underside.

The panda is typically herbivorous, feeding almost exclusively on bamboo (Cockrum, 1962; Morris and Morris, 1966; Schaller, 1985; Schaller et al, 1989). It has developed a number of physiological adaptations to accommodate such a specialized diet. The panda has atypically ursid dentition (13/3 C1/1 P4/4 M2/3 = 42), though highly modified for its diet of bamboo. The cheek teeth are large and blunt and covered with tubercles to serve as a grinding surface for cellulose-laden materials such as bamboo. The same is true of the premolars, a condition not seen in other bears (Schaller, 1985). To power these grinding devices, the panda has huge masseter muscles that close the jaws during chewing. The masseters are attached at the sagittal crest, which is especially prominent in the panda to accommodate the large size of the jaw muscles.

Another adaptation that aids in the processing of bamboo is the panda' s "pseudothumb." This pseudothumb is actually the radial sesamoid, an elongated wristbone (Morris and Morris, 1966). A fleshy pad not unlike the toe pads found under the panda's true toes covers the bone. The pseudothumb can be opened and closed much like an opposable thumb. This allows the panda to manipulate bamboo in such a way that the animal can wedge stalks between its true toes and the pseudothumb. Thus, the panda can feed by bring food up to its mouth, rather than dipping its head to the ground to reach its food source. As such, a feeding panda is often found processing its bamboo in a seated or reclining position, using its forepaws to lift bamboo stalks.

The panda’s digestive tract has also evolved to accommodate its fibrous diet to some degree. The esophagus is thickly lined to protect the membranes from the bamboo fragments, and the stomach is thick and muscular, much like the gizzard of a bird (Morris and Morris, 1966). However, the intestinal tract does not appear to be well adapted to processing fibrous material. The panda's digestive tract is short, which prevents efficient absorption of nutrients and the breakdown of herbivorous substances (Schaller et al, 1989). This inefficiency in nutrient absorption means that pandas must consume large quantities of food to survive.