What makes a panda black and white?
Scientists have thrown up plenty of potential reasons for the contrasting colors of the giant panda bear. Could they be for stealth, regulating temperature or a warning to potential predators? Researchers now believe they know the reasons behind the iconic black and white patches: a need for camouflage combined with a need to communicate.
The scientist that led the research, Tim Caro, has some experience in uncovering the secrets behind another animal's distinctive coloring. A professor at University of California, Davis, in 2014 he published a paper in the journal Nature Communications, revealing that the reason zebras have stripes is to deter biting flies. He arrived at this conclusion by reviewing literature on other mammals in the horse family and found that striped species occurred in locations where biting flies were abundant.
But the issue with tackling the same problem in the panda bear is that there is no animal like it; it stands alone as a black-and-white outlier among mammal species, which makes comparisons difficult. But the team overcame this by breaking down the different parts of the body and treating them as independent areas.
Through this method, the team compared patches of fur from the panda's body to the dark and light coloring of 195 other carnivore species and 39 related bear sub-species. They then examined associations with the various hair colorings and the animal's environment to work out what purpose they served.
The results led them to conclude that the majority of the panda's body, including its face, neck, belly and behind, is white to help it blend into snowy habitats. Its arms and legs meanwhile, are black to help it hide in the shade. Interestingly, the black markings on the head seem to have nothing to do with camouflage, but rather are used for communication. The dark ears may help them seem fierce when the time is right, as a warning to predators, while the dark patches around the eyes might be used for communication, helping pandas recognize one another or signal aggression.
The team suggests that pandas evolved their two-tone appearance due to their poor diet of bamboo, which meant that they were never able to store enough fat to go dormant during the winter like some bears. So because they had to be on the move year-round, they had to be able to hide in a variety of habitats ranging from snowy mountains to tropical forests.
"This really was a Herculean effort by our team, finding and scoring thousands of images and scoring more than 10 areas per picture from over 20 possible colors," said co-author Ted Stankowich, a professor at California State University, Long Beach. "Sometimes it takes hundreds of hours of hard work to answer what seems like the simplest of questions: Why is the panda black and white?"
The team's research was published in the journal Behavioural Ecology.
Source: University of California, Davis via EurekAlert