Before you freak out that your dog may be suffering from canine conspecific coprophagy, know that it's probably not that serious—though you will likely be grossed out. Scientific American reports on a study in the Veterinary Medicine and Science journal that looked at the result of two web-based surveys of about 3,000 dog owners in the US and Canada, with a finding that 16% of the owners said they'd witnessed their pups eating dog poop, either their own or that of other dogs, on at least six occasions. The second survey, which focused exclusively on poop-ingesting dogs, revealed that 62% of those pets ate stool daily, while 38% did so weekly. The UC-Davis researchers couldn't pinpoint definitive links among the poop eaters, such as age, gender, diet, or how easily they'd been house trained.
The scientists did find clues as to what separates feces feasters from those that don't partake. Coprophagic canines more often live with other dogs (pointing to a possible social factor), and they also tend to be "greedy eaters" that "wolf down food." That 85% of the poop eaters preferred fresh stool (not more than two days old) led researchers to speculate that the habit traces back to dogs' wolf ancestors, which may have eaten parasite-infected poop near their dens before the parasite eggs hatched, per the Washington Post. Although dogs often suffer no ill effects from poop consumption, vets say some could be hit with diarrhea or be exposed to disease. As for trying to put a halt to the habit, dog owners in the study said trying products designed specifically for that task had a success rate of 2% at best; behavior modification techniques didn't help much, either. (Don't use your Roomba to clean up your dog's mess.)