They could just be attracted to the strong smell of horse poop.
In the mountain reserves of central China, giant pandas have long been observed coating themselves in horse manure — a behavior that puzzled scientists until now. Researchers believe the dung contains chemical compounds that suppress cold-sensing receptors, offering the bears a form of thermoregulation in a life where hibernation is impossible and bamboo provides little warmth. The discovery invites us to reconsider how ancient and varied the strategies of survival can be, and how the line between instinct and ingenuity is rarely as clear as we imagine.
- Giant pandas, unable to hibernate and poorly insulated by their bamboo diet, face a genuine winter survival problem — and their solution appears to be rolling in horse dung.
- Infrared cameras captured 38 instances of this behavior, always with fresh manure and always spiking in colder months, suggesting something far more purposeful than random curiosity.
- Lab tests on mice coated with the manure's key compounds showed striking cold tolerance — the animals walked across freezing surfaces without distress while untreated mice huddled immediately.
- The mechanism is molecular: beta-caryophyllene compounds block the body's cold-sensing receptors, muting the distress signal much like capsaicin creates warmth through a parallel pathway.
- Not everyone is convinced — one skeptic warns that numbing the sensation of cold could prevent pandas from seeking shelter, potentially turning a survival strategy into a dangerous vulnerability.
In the mountains of central China's Foping National Nature Reserve, giant pandas do something that seems to defy all instinct: they roll in horse manure, coating their necks, faces, and bodies in dung from animals they would never naturally encounter. For years, the behavior baffled researchers. Now, a team of scientists believes they have found the answer — the dung may help pandas survive the cold.
Analyzing 38 camera-captured instances between 2016 and 2017, researchers noticed the pandas consistently chose fresh droppings — less than ten days old — rich in two compounds called beta-caryophyllene and beta-caryophyllene oxide. The rolling behavior peaked during colder months, pointing toward thermoregulation rather than scent marking. When the compounds were added to hay at the Beijing Zoo, pandas not only preferred the treated food but rubbed it on their bodies, mirroring their wild behavior.
Because China's strict protections prevent direct experimentation on pandas, the team tested the compounds on mice. Treated animals showed measurably improved cold tolerance, walking freely across frigid surfaces while control mice huddled together. At the cellular level, the compounds worked by blocking the receptors that signal cold — effectively muting the body's distress response to low temperatures.
The findings carry particular weight given the panda's biology. Unlike most large mammals, pandas do not hibernate, and their near-exclusive bamboo diet provides too few calories to build insulating fat. An ecologist at China West Normal University suggests pandas may have relied on this strategy for thousands of years, as ancient trade routes brought horses through their mountain habitat.
Not all scientists are persuaded. Malcolm Kennedy of the University of Glasgow argues that pandas will smear almost anything unusual on their bodies, and questions whether blocking cold sensation could backfire — if the bears stop feeling cold enough to seek shelter, the behavior could prove dangerous rather than protective. Whether the pandas have discovered an ancient survival solution or stumbled into a risky habit remains an open question.
In the mountains of central China's Foping National Nature Reserve, giant pandas engage in a behavior that seems to defy every instinct about cleanliness: they roll in horse manure, coating their necks, faces, and entire bodies in dung. For years, researchers could only puzzle over why these solitary bears would seek out and wallow in feces from animals they never naturally encounter. Now, a team of scientists believes they have cracked the mystery. The horse poop contains chemical compounds that may help pandas survive the cold.
When researchers analyzed 38 instances of this behavior captured on infrared cameras between June 2016 and July 2017, a pattern emerged. The pandas consistently chose dung less than ten days old—fresh enough to contain high concentrations of two compounds called beta-caryophyllene and beta-caryophyllene oxide. Older droppings lacked these chemicals in meaningful amounts. More tellingly, the rolling behavior spiked during colder months, when temperatures ranged from minus five to fifteen degrees Celsius. The connection suggested something beyond mere curiosity or scent marking.
To test their hypothesis, researchers at the Chinese Academy of Sciences's Institute of Zoology added these compounds to hay fed to pandas at the Beijing Zoo. The animals showed a clear preference for the treated food, sometimes rubbing it across their bodies just as they would with horse manure in the wild. The behavior appeared deliberate, purposeful—not random play. But proving that these chemicals actually helped the bears stay warm presented a challenge. China's strict protections on giant pandas, designated a national treasure, severely limit direct experimentation on the animals themselves.
So the team turned to mice. When researchers coated the rodents in a diluted solution of the compounds, the treated animals displayed measurably improved tolerance to cold. They walked readily across frigid surfaces and did not huddle together even in below-freezing conditions, behaviors the control group exhibited immediately. At the cellular level, the scientists discovered how the compounds worked: they blocked the receptors in the body that sense and signal cold. By muting that signal, the pandas—and the mice—could function in lower temperatures without triggering the usual distress responses.
The findings, published in the Proceedings of the National Academy of Sciences, offer an elegant explanation for a behavior that had long seemed inexplicable. Fan Yang, a biophysicist at Zhejiang University, praised the research as providing "solid evidence from the molecular level" to explain the pandas' unusual habit. He noted that the same cold-sensing receptors exist in many species, from elephants to penguins to humans, suggesting that this thermoregulation strategy might be far more widespread in nature than previously recognized. Capsaicin, the compound in chili peppers that makes humans feel warm, works through a similar mechanism—activating receptors that create the sensation of heat.
The timing of this discovery carries historical weight. Giant pandas face genuine challenges staying warm during winter months. Unlike many mammals, they do not hibernate. Their diet consists almost entirely of bamboo, a food so low in calories that the bears cannot accumulate the fat reserves necessary for insulation. An ecologist at China West Normal University, Zejun Zhang, points out that pandas may have relied on this thermoregulation strategy for thousands of years, as ancient trade routes crossed through the mountainous terrain where horses would have passed through regularly, leaving their mark on the landscape.
Yet not all experts accept the explanation. Malcolm Kennedy, a professor of natural history at the University of Glasgow, remains skeptical. Pandas, he argues, will smear almost anything unusual or interesting onto their bodies, and they may simply be attracted to the pungent odor of horse dung. More fundamentally, he questions whether the strategy could actually benefit the animals. Even if blocking cold-sensing receptors prevented the bears from feeling discomfort, their bodies would still require more energy to maintain function in low temperatures. If the compounds dulled the sensation of cold enough to stop pandas from seeking shelter, Kennedy suggests, the behavior could prove "potentially suicidal" in extreme conditions. The question of whether the pandas have truly solved a survival puzzle or merely stumbled into a risky habit remains open.
Citas Notables
Provided solid evidence from the molecular level to elegantly explain the unique behavior— Fan Yang, biophysicist at Zhejiang University School of Medicine
Could be potentially suicidal if it prevents animals from seeking shelter in extreme conditions— Malcolm Kennedy, professor of natural history at University of Glasgow
La Conversación del Hearth Otra perspectiva de la historia
So pandas are deliberately coating themselves in horse manure to stay warm? That seems almost too strange to be true.
It does sound absurd, but the evidence points in that direction. They're selective about it—only fresh dung, only in cold weather. That's not random behavior.
How did researchers even figure this out? You can't exactly ask a panda why it's rolling in poop.
They watched the patterns on camera, then tested the chemicals in the dung on other animals. Mice treated with the compounds actually tolerated cold better. It's indirect, but it's methodical.
But couldn't the pandas just be attracted to the smell, like the skeptic suggests?
Maybe. But why would smell alone explain why they do it more in winter, or why they prefer fresh dung over old? The timing and selectivity suggest something more purposeful.
If blocking cold sensation helps them, why wouldn't all animals do this?
That's the real question. Most animals would probably just seek shelter instead. For pandas, which don't hibernate and eat low-calorie bamboo, maybe this is a survival workaround that's worth the risk.