Explaining the gross behavior was an epic scientific journey
It was a strange sight: In the winter of 2007, scientists in China spotted a wild giant panda romping about in horse manure, diligently smearing itself with excrement until its fur became a poo-muddled mess. It wasn’t the last time the researchers would spot this strange behavior.
But figuring out why pandas do this would take the team 12 years and a scientific trek through the fields of animal behavior, chemical ecology and neurophysiology. But now, researchers think they have an answer.
“I’m a panda expert, and this is one of the strangest panda papers I’ve ever read,” says Bill McShea, a biologist at the Smithsonian Conservation Biology Institute in Front Royal, Va. “There’s still a lot of work to be done, but these researchers deserve a lot of credit.”
Students of Fuwen Wei, an ecologist at the Chinese Academy of Sciences in Beijing, first glimpsed the bizarre behavior deep in the Qinling mountains of central China. The region is crisscrossed by ancient trade routes well-trod by horses, so the researchers say horse manure may have been common.
Rolling around in poop isn’t unheard of among animals — consider the dog. But many mammals actively avoid the fecal matter of other individuals and species, as poop can harbor pathogens and parasites, says Cécile Sarabian, a cognitive ecologist at Kyoto University in Japan who wasn’t involved in the study.
“Behavior is a story of compromises,” she says. “In this case, the benefits of getting in contact with fresh horse manure may override the [potential] risks.”
To understand what those benefits might be, the researchers first had to catch more manure maneuvers. They set up a series of motion-sensitive cameras along roads in the Foping National Nature Reserve. The cameras captured 38 panda-poo interactions from July 2016 to June 2017, suggesting that the initial observation wasn’t just a freak incident. The camera setup also recorded the time and air temperature for each behavior, revealing a clear pattern: Giant pandas rolled in poop only in colder weather. The majority of observations were captured when temperatures were between –5° Celsius and 5° C.
