Giant panda to digest cellulose is ascribed to the microbes in its gut. Pandas are born with sterile intestines and require bacteria obtained from their mother's feces to digest vegetation. 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 lb) of bamboo shoots a day to compensate for the limited energy content of its diet. Ingestion of such a large quantity of material is possible because of the rapid passage of large amounts of indigestible
Giant panda urine. They are able to climb and take shelter in hollow trees or rock crevices, but do not establish permanent dens. For this reason, pandas do not hibernate, which is similar to other subtropical mammals, and will instead move to elevations with warmer temperatures. Pandas rely primarily on spatial memory rather than visual memory. Though the panda is often assumed to be docile, it has been known to attack humans, presumably out of irritation rather than aggression. Initially, the primary method of breeding giant pandas in captivity was by artificial insemination, as they seemed to lose their interest in mating