Many theories of panda coloration have been advanced over the centuries. Tibetan legend has it pandas are constantly mourning their fallen relatives, and so have sad eyes, and wear black arm sashes to commemorate the fallen.
More modern postulation has attributed their markings to the temperature regulation and daytime glare — ensuring they can stay comfortable whatever the habitat, whatever the time of year, and can see in intense sun.
The biggest threats to pandas are everyday human actions — their existence is threatened by habitat loss and fragmentation, and by people harvesting plants in forests. Moreover, panda patterning doesn't look like the type of disguise one would adopt to blend in with one's surroundings, especially if you can weigh as much as 160 kilograms (350 pounds).
Nevertheless, a new study by University of California scientists, published in Behavioral Ecology, may have the answer to the age-old riddle.
To find out the secret of the panda getup, scientists compared panda pelage to the dark and light coloring of 195 other terrestrial carnivore species and 39 bear subspecies, then matched their patterns against environmental conditions and social behaviors.
The scientists found no link between temperature and coat color, or any association between eye markings and daytime glare. They did however find a connection between lighter colors and snow cover, suggesting a panda's white markings help hide the animal in snowy habitats.
Meanwhile, darker markings likely hide them in the forest, where they face their worst enemy — leopards. Pandas, the researchers feel, evolved both colors as a compromise, because they are active year-round in both habitats.
This of course leaves the question of a panda's face patches, although the analysis may have solved this too — the markings on carnivores' heads are not used for camouflage, but to communicate.
Pandas cover their eyepatches with their paws when they don't want to seem aggressive.
Other studies have shown pandas are capable of remembering these patches, which can vary wildly in size and shape. These patches can also be enlarged when a panda stares at a competitor.