Hobbies And Interests
Diet
The unique diet of the giant panda dictates its existence. The animal is essentially a specialized herbivore in a carnivore's body, a physiological conundrum that the panda addresses both morphologically and behaviorally. The gut of the giant panda is the simplified one of a carnivore evolved to process meat, which is easier to digest than fibrous, cellulose-based plant materials. Compare its basic gastrointestinal tract to the multiple-chambered stomachs and cud-chewing of the hoofed mammals called ruminants, adaptations to extract as much nutrition as possible from rough forage. Because giant pandas are far less efficient at processing bamboo, they must spend most of their waking hours eating constantly and limiting energy expenditures: they may consume over 80 lbs. a day. The benefit of the diet is bamboo's abundance and year-round availability.
Other Feeding Adaptations
The giant panda's digestive tract is heavily lined with mucus, thought to act as a buffer against the sharp edges of masticated bamboo. The panda's molars are high-walled and flat-edged like those of many other herbivorous animals. And their jaws are very powerful: massive cheek muscles rig to the high sagittal crest (a sharp ridge of bone on the crown of the skull) and broad zygomatic arches, well-designed to mash apart resistant stalks and foliage. Most intriguingly, pandas possess a false thumb on their forepaws. This modified spur-bone approximates the function of a primate's opposable thumb, allowing the panda to delicately grip bamboo stalks and twigs.
Environmental Influences
The giant panda's need for sustenance keeps it tied to the mixed broadleaf and conifer forests that shade rich understory bamboo groves and thickets. (While the giant grass comprises 99 percent of a panda's typical diet, the bears will occasionally eat fruits, insects and small animals.) The patterns of bamboo reproduction -- in a given region, all plants of the same species flower and then die at once -- help drive panda movements within their home range. They obtain water from their bamboo forage and mountain streams. Giant pandas do not hibernate, though in the winter they often move downslope to lower country. They take shelter from the elements in caves and hollows.
Reproduction
As giant pandas usually travel alone in overlapping or shared home ranges, males first locate receptive females through scent-marks and, at closer range, vocalizations. The gestation period may last 160 days before the female bears one or two cubs (only one typically survives), which are smaller at birth in proportion to the adults than any other mammal outside the marsupials. Cubs may remain dependent on their mother for several years.