Pandas "sniff out fresh horse droppings, lay themselves down and roll their bulky bodies in the muck, using their paws to really make sure they are covered..."

"... from the tip of their fuzzy ears to the bottom of their tails, until their black and white fur is another shade entirely.... A team of researchers led by Fuwen Wei, a biologist at the Chinese Academy of Sciences, first noticed a panda luxuriating in a pile of horse excrement in 2007. Unsure of whether it was a fluke, they spent years tracking the bears with dozens of camera traps, eventually convincing themselves that the behavior was 'definitely frequent and typical'.... Drawn to the irresistible stink of the droppings — the fresher the better — the bears would first take a careful whiff, then initiate a gentle rubbing with a cheek. They would next immerse themselves in an unbridled full-body tussle in the dung, before meticulously slathering themselves with their paws to ensure all their exposed bits were covered... The researchers propose that this filthy act is all about tolerating low temperatures.... A chemical analysis of the dung revealed two short-lived compounds called sesquiterpenes.... When applied onto the paws and fur of laboratory mice, the sesquiterpenes rendered the rodents indifferent to frigid temperatures or a chemically induced chill. Further lab experiments showed the sesquiterpenes were gumming up a type of cold-sensing protein that adorns the cells of pandas and many other animals, including humans."

From "Why Are Pandas Covering Themselves With Horse Manure?/Researchers in China spent a decade studying this question" (NYT).