For a species that tends to be portrayed as noble, intelligent, and discriminating, some dogs sure do love to eat poop. Their fecal snacking extends to foreign excrement, litter boxes, and even their own waste. Some have been known to contort their bodies and devour a number two as it exits, refusing to let the waste go to waste.

Why do some dogs become fecal vacuums while other turn their nose at it? There’s no one definitive answer, but there are a few pretty reasonable suggestions.

Benjamin Hunt, Ph.D., a veterinary behaviorist and professor at the University of California, Davis, published a study in 2012 that surveyed 3000 pet owners. His research discovered that 16 percent of the sampled dogs had practiced coprophagia—eating poop—at least five times. Of those, nearly all had devoured another dog’s deposits. Interestingly, over half of the guilty parties were identified as “greedy eaters” who would snatch food from tables. Hunt also learned multi-dog households were more likely to encounter the behavior, possibly because their backyard doubles as a fecal buffet.

These poop munchers likely all have one thing in common: mommy issues. “Puppies don’t have the reflexes at birth to initiate urination or defecation on their own, and they require their mother to stimulate them,” says Nick Dodman, a professor at the Cummings School of Veterinary Medicine at Tufts University. Mom licks their behinds, eats whatever they produce, and also cleans the “nest” of larger deposits the only way she can. “Puppies are greeted by their mum eating feces. To them, that’s what the world does.”

While some outgrow the behavior, other dogs keep eating, typically preferring fresh stool over stale offerings. (In Hunt’s study, most turd tasting was done less than 24 hours after elimination.) Dodman theorizes diets that are low in residue tend to produce softer, tastier movements, and that switching to a high-fiber menu may prompt an aversion to poop. “The texture is completely different. Instead of a tasty toothpaste, it’s something more like cardboard.”  

Of course, that won’t stop your pet from gobbling someone else’s leftovers. “It’s sort of like trying to give up cigarettes,” Dodman says.

If a dietary change doesn’t work, it’s best to pick up waste often so they’re not tempted—or get a poodle. Of all the animals in Hunt’s sample, the breed had no documented habit of scatological snacking. 

Additional Sources:
“Canine Conspecific Coprophagia; Who, When and Why Dogs Eat Stools [PDF]”