Pandas are black and white because it helps them hide from predators, according to new research.
The iconic bear's distinctive coat is effective camouflages in nature — across a range of environments.
The giant panda's striking appearance has baffled evolutionary experts for decades. Now rare photos of pandas in the wild and state-of-the-art scans have shown the panda's unique colorings work as a disguise.
This came to light as biologists looked at wild panda pictures — and realized they couldn't see the animals in the shots. Co-author of the new research, Professor Tim Caro of the University of Bristol, told SWNS, "I knew we were on to something when our Chinese colleagues sent us photographs from the wild."
"I couldn't see the giant panda in the picture. If I couldn't see it with my good primate eyes, that meant 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," he added.
Most mammals are drab browns and greys, with a few exceptions — like zebras, skunks, and orcas. The giant panda is perhaps the most famous. Its face, neck, belly, and rear are white to help it hide in snowy habitats, and the arms and legs are black — making it hard to spot in the shade.
The new findings in Scientific Reports show the panda's need for dual coloration. The requirement stems from its poor diet of bamboo and inability to digest a wider variety of plants. Pandas can never store enough fat to go dormant during the winter — as other bears do. So pandas have to be active year-round, traveling across long distances and habitat types that range from snowy mountains to tropical forests.
Analysis of the photos — taken in the panda's natural environment — found its black patches blend in with the dark shades and tree trunks of the jungle. Meanwhile, the animal's white areas match foliage and snow when present. In rare cases, brown hair emerges, which fits in with the ground. The intermediate color bridges the gap between the very dark and very light surroundings.
Results were based on computer models that represented the vision of a variety of species. The panda's coloring remained effective camouflage whether images were "viewed" by humans, jackals, snow leopards, or yellow-throated martens. The latter three kill and eat pandas.
Lead author Dr. Ossi Nokelainen of the University of Jyvaskyla, Finland, said, "The rare photographic evidence allowed us to examine the giant panda's appearance in its natural environment for the first time."
"With the 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 modeling techniques and also to explore their disruptive coloration," he added.
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Disruptive coloration is a form of camouflage in which highly visible boundaries on the surface of an animal break up its outline. In the panda's case, these are borders between the large black and white patches of fur.
The researchers found giant pandas show this form of defensive coloration, especially at longer viewing distances. Finally, a color mapping technique compared the panda's "similarity-to-background" metric, and it confirmed the giant panda fell solidly within other species that are traditionally considered as well camouflaged.
Co-author Professor Nick Scott-Samuel, a psychologist at Bristol, added, "It seems giant pandas appear conspicuous to us because of short viewing distances and odd backgrounds. When we see them, either in photographs or at the zoo, it is almost always from close up, and often against a backdrop that doesn't reflect their natural habitat."
"From a more realistic predator's perspective, the giant panda is actually rather well camouflaged," he added.