Why are giant pandas black and white? This is how we found out


IUnlike many flaming bird species, most of the 5,000 species of mammals are dull brown or gray in color. But there are a small number of well-known and intriguing exceptions, including zebras, skunks, and orcas.

However, perhaps the most famous of all are the giant pandas. We already had a preliminary idea of ​​why they had their marks, but we wanted to confirm the reason for its mysterious pattern.

Seen up close in a zoo, the giant panda is a striking and remarkable mix of a polar bear with black front legs, shoulders and hind legs, and an extraordinary face with black fur around the eyes and ears. By comparing these different body parts with the coloring of other carnivores (contrary to popular belief pandas are officially classified as carnivores) and also with bears, it was already known that white-backed carnivores are found in snowy environments and those with dark legs and paws. shoulders are found in shady habitats. This suggested that the fur was an adaptation to be camouflaged in different environments.

Nowadays, giant pandas are confined to the remote forests of western China, where there are relatively few predators. But we had to confirm that the camouflage was effective against the ancient predators of the giant pandas: tigers, leopards, Asian black bears and dholes (a wild dog) from the time they roamed China to Vietnam.

The breakthrough came when we teamed up with colleagues from the Chinese Academy of Sciences Yong-gang Nei and Fu Wen Wei. They work with giant pandas in the field and had rare photographs of wild giant pandas. Importantly, the photos in their natural habitat were taken from a distance.

We used state of the art image analysis to demonstrate that the unique colorations indeed work to disguise the giant panda.

By matching the reflectance (the amount of reflected light) of the giant panda’s fur with natural objects in the background, we found that their black fur patches blend in dark tones and with tree trunks, while their white spots correspond to shiny foliage and snow when present. . In addition, an infrequent pale brown muddy-colored fur matches the color of the soil. This provides an intermediate color that bridges the gap between the very dark and very light visual elements of the natural habitat.

In the wild and at a distance, our research shows that they are beautifully camouflaged, using two different mechanisms to avoid detection.

These results are consistent whether seen by human, feline, or canine vision models. The visual systems of domestic dogs and cats are well known and are good substitutes for the visual systems of natural giant panda predators such as tigers and wild dogs.

Next, we looked at a second form of camouflage – called disruptive coloring – in which highly visible spots on an animal break up its outline by blending in with spots in the background.

We have found that giant pandas exhibit this form of defensive coloration, especially at longer viewing distances of at least 60 meters. At these distances, the outline of the giant panda becomes difficult to recognize as the patches of black fur blend into the background of dark rocks and tree trunks.

Finally, we used a new color mapping technique to compare how well various animals, including the giant panda, blend into their background. This comparative analysis confirmed that the substantive resemblance of the giant panda fits firmly into the group of other species traditionally considered to be very well camouflaged, right next to shore crabs and crabs. jerboas (desert rodents).

So although giant pandas in zoos or other places of captivity are very visible to us, it is because we see them up close and surrounded by artificial backgrounds, but when they are in the wild. and from a distance, our research shows that they are beautifully camouflaged, using two different mechanisms to avoid detection.

Giant pandas are a highly regarded species and are now doing better in the wild thanks to extraordinary conservation efforts. The future of this species is therefore cautiously optimistic.

Tim Caro is a professor in the School of Biological Sciences at the University of Bristol. Nick Scott-Samuel is Professor of Experimental Psychology at the University of Bristol. Ossi Nokelainen is a postdoctoral researcher at the University of Jyvaskyla, Finland. This article first appeared on The conversation.


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