Social Habits
Recent studies of these cuddly-looking but antisocial black-and-white animals indicate that pandas mark their territory with scent, using their urine and feces. While territories may overlap, pandas tend to avoid coming close enough even to see one another. They also monitor each other's location by sound --- grunts, clicks, snorts and other vocalizations.
Forced Contact
If several pandas are in an enclosure together, they usually separate, each to its own space, and become absorbed in individual activities such as feeding, ignoring the others.
Breeding
Breeding season may result in pandas grouping together, one female with multiple males. Captive pandas do not seem to have instinctive knowledge of normal breeding behavior and need to learn it from "panda porn" videos. The only other time you are likely to see more than one panda at a time is when a female has cubs that are not ready to leave their mother.
Cohabitants
Because giant pandas are so rare, no one has tried to introduce them to other species, in case of accidents or direct violence. While there are no reports of pandas adopting "companion animals" as pets, the way gorillas and race horses are known to do, they do share their habitat with other endangered species such as their cousins the red panda, the golden monkey and the golden pheasant. An extremely rare species of hoofed animal, the takin, also ranges through panda habitat; they look something like a goat crossed with a woolly Merino sheep.