The secret of precisely why giant pandas are coloured black and white has been uncovered by a team of scientists from Britain, China and Finland, a question that has puzzled experts for generations.
While the bears’ distinctive high-contrast colouring means they stand out in the unnatural surroundings of a city zoo, where most humans encounter them, the opposing shades of their fur actually plays a counterintuitive but crucial defensive role in the mountain forests where they would normally reside, the new study found.
“The giant panda uses black-and-white pelage as a form of crypsis to avoid detection in its natural habitat,” the scientists from the University of Bristol, the Chinese Academy of Sciences and the University of Jyvaskyla wrote in the academic journal Scientific Reports, concluding that the combined extremes allow them to camouflage themselves more effectively against different aspects of a given backdrop, helping them evade intrepid predators like leopards, tigers and dholes (Asiatic wild dogs).
“The black fur blends into dark shades and tree trunks, whereas white fur matches foliage and snow when present, and intermediate pelage tones match rocks and ground,” the team wrote.
The patchiness of their fur’s colouring also appears to confuse perceptions of their outline, making their exact shape more difficult for would-be antagonists to determine and perhaps discouraging an attack.
Alternative explanations previously proposed for pandas’ unique colouration have included intraspecific signalling, heat management and aposematism (deterring rivals) but it appears background matching for survival is the likeliest answer.
The team’s findings were based on examining photographs of 15 different pandas taken between 2007 and 2014 in Sichuan, Shaanxi and Gansu provinces in the humid and remote wilds of south central China, which were analysed against the forest, rocks and rivers that comprise the fragmented background of those locations.
Dr Ossi Nokelainen, the study’s lead author, said: “The rare photographic evidence allowed us to examine the giant panda appearance in its natural environment for the first time.
“With help of the state-of-the-art image analysis, we were able to treat these images as if the pandas would have been seen by their predator surrogates using applied vision modelling techniques and also to explore their disruptive colouration.
“Comparative results totally bust the myth of giant pandas being overtly conspicuous in their natural habitat.”
Professor Tim Caro of the school of biological sciences at the University of Bristol, commented: “I knew we were onto something when our Chinese colleagues sent us photographs from the wild and I couldn’t see the giant panda in the picture.
“If I couldn’t see it with my good primate eyes, that meant that would-be carnivorous predators with their poorer eyesight might not be able to see it either. It was simply a matter of demonstrating this objectively.”
Professor Nick Scott-Samuel, also from Bristol, added: “From a more realistic predator’s perspective, the giant panda is actually rather well camouflaged.”