Giant pandas have been seen smearing themselves with horse manure in the wild, and the sweet smell of the feces isn’t the only reason – it appears the manure helps them tolerate low temperatures, study finds.
Unlike insects which make a straight line for feces, digging for scent clues to locate food, the attraction of feces through mammalian species is rare. But researchers at the Chinese Academy of Sciences observed that a subspecies of the giant panda from the Qinling Mountains in China tended to seek and sniff fresh horse manure, then roll over it.
Researchers installed infrared cameras in the wild between July 2016 and June 2017 and captured 38 events of this rolling behavior, which mostly occurred when the ambient temperature was below 15 ° C (59 ° F).
The behavior also appears to be related to feces less than 10 days old. When scientists compared fresh manure to older feces, they found that fresh feces were rich in two compounds: beta-caryophyllene and caryophyllene oxide.
Due to the apparent correlation in temperature, the scientists wondered if the two compounds were somehow involved in thermal sensation in mammals, so they conducted another experiment. They treated one group of mice with both compounds and another group with saline, finding that mice treated with the compound tolerated cold temperatures better.
The researchers then found that at the molecular level, the two compounds interact with a heat-sensitive pathway in pandas, inhibiting cold activation, they said in an article published in the journal Proceedings of the National Academy of Sciences.
Dr Claudia Wascher, a behavioral ecologist from Anglia Ruskin University who was not involved in the study, said: ‘In general, many species avoid feces and show disgust with feces, which can happen. explain as an evolved strategy to avoid parasites and infections. I haven’t heard of pandas rolling in horse manure, but I know of other species that roll in the droppings of other species, for example dogs. I wouldn’t be surprised if more species show similar behavior.
“It reminds me a bit of self-medication in some species: for example, primates are known to self-medicate, so eat specific types of plants when they feel sick.”
Dr Simon Girling, chief veterinarian at Edinburgh Zoo, which is home to the UK’s only two giant pandas, said the study was insightful given that most of the research material focused heavily on olfaction and pheromones in the stool.
“We have always understood that olfaction is a very important sense for this particular species,” he said. “When people say they divide the genome of this, that, and the other – what’s the point? Well, here’s a very interesting example, it starts to unlock our understanding of the biology of this particular species and how it can adapt.
Would Edinburgh’s two pandas – Tian Tian and Yang Guang – receive fresh horse manure to anoint themselves in winter? “It’s definitely a possibility,” Girling said.
He warned that horse feces could contain salmonella bacteria. “But potentially, if it was possible to isolate these compounds in a safe way, it just might be something that could be used as an enrichment tool. “