“Bamboo”zled by pandas’ colors no more

HANNAH LEE / AGGIE

UC Davis, CSU Long Beach scientists discover why pandas are black and white

Pandas, while charismatic and fascinating, have tantalized humankind with one age-old question: why are they black and white? A new study conducted by scientists at UC Davis and CSU Long Beach has presented us with the answer to this enigma.

“We started by breaking down a general mammalian carnivore body into 13 regions and a general face into 12 regions,” said Theodore Stankowich, co-author of the study and an assistant professor at CSU Long Beach. “We then gathered about 2,500 photos of animals covering 195 species of mammalian carnivores, and gave each body region a color score in every picture. We compared these colors to the environmental factors, like snowfall, temperature, habitat type that each species experienced, as well as the type of social system they live in.”

According to the researchers, examining each region of the panda’s body independently was a major asset in the success of this study. Using this approach, researchers could assign different functions to different regions of the panda body by comparing them to those of related species.  

“If one tries to find similar species to the great panda, there are virtually none,” said Tim Caro, the lead author of the paper and a professor in the UC Davis Department of Wildlife, Fish and Conservation Biology. “But if one breaks up the body into regions — say white backs, black legs — there are many carnivores with similar coloration in those areas. Now one can ask what biological factors are associated with darks legs and white backs across carnivores.”  

The scientists found that the panda’s face, stomach, neck and hind were white so the the panda could camouflage in the snow. The arms and legs were black so that it could hide from predators in the shade.

This combination of black and white coloration is due to an interesting handicap of the great panda. Because the great panda consumes a very low-quality diet of bamboo, it cannot hibernate and must remain active all year. To get a sufficient amount of bamboo, it lives in both shady and snowy habitats throughout the year and therefore requires the dual coat coloration to hide from predators in both environments.

“Their body coloration is really a compromise between those two habitats to be camouflaged from potential predators during the entire year,” Stankowich said.

That still leaves the question of the panda’s endearing black eye patches and dark ears. The scientists determined that these regions of the panda’s head signified the function of communication. The dark eye patches help pandas recognize one another or signal aggression towards competitors, while the dark ears serve as a warning for predators.

“Now when someone wonders ‘why does a panda look like that?’ they actually have an answer,” said Zoe Rossman, another co-author of the paper. “It’s an easy way to introduce or expand on knowledge of evolution and animal behavior from kids to adults, and the more people know about these topics, the more people will hopefully care about protecting animals and the environment.”
Written by: Harnoor Gill — science@theaggie.org