It seems like every few months a study comes out touting the benefits of pet ownership. According to the claims, stroking pets lowers our blood pressure, dog companions increase our exercise, and going to the dog park improves our sociability. But what most studies fail to reveal is the dark, dirty secret that up to 16% of dog owners don’t want you to know: THEIR dogs eat poop…a lot!

Yes, according to a study presented at the annual ACVB/AVSAB Behavior Symposium in San Diego last month, 16% of dogs are serious stool eaters. That means they have been seen doing it 5 times and 24% have been caught in the act at least once. Dr. Benjamin Hart, a board certified veterinary behaviorist at the University of California, Davis, conducted the study that consisted of two web-based surveys. The first yielded 1,548 usable returns and was about dogs and their traits in general. Dr. Hart also inconspicuously slipped in a few questions about stool eating so that researchers could compare non-stool eaters with stool-eaters to look at the numbers of each as well as the characteristics and factors associated with the behaviors. The second survey was just for pooches that had been observed eating poop more than 10 times. Hart received 1,400 usable surveys.

For those of you who are set on making sure you never get a dog with this despicable and stinky trait, the survey revealed some important factors you may want to know. For instance, Hart found, “The more dogs you have the more likely your dog will eat poop. The smallest percent (19%) of poop eaters were in single dog homes whereas 24% lived with two dogs and 30% lived in a three-dog household.”

Why would that be? It could have to do with the fact that while 15% of the stool-eaters ate their own poop, 85% ate the feces of other dogs. So more dogs probably equals more opportunity to eat another dog’s digested food. Yuck! Why is that somehow grosser than dogs eating their own?

Before you raise your hands wildly and proclaim that the dog must be lacking something in his diet, read on. “We found that diet of the dog had no effect,” says Hart. They did however find that gender and sexual status mattered somewhat. “Intact males were the least likely to eat stool. Neutered males were more likely, and spayed females the most likely at 19%.” says Hart.

My theory why this would be? Perhaps the intact males were thinking about other things (like sex!).

There were also some breed dispositions: 38% of border collies had a history of eating poop and 40% of shelties did, too. Now that’s something that probably will never show up in a breed description. Which breeds ate poop the least? Hart stresses there weren’t enough dogs to tell, but he points out, “None of the poodles in the study ate their stool”.

Now, Hart’s original hypothesis was that perhaps some dogs eat poop because they are messy….slobs. But the fact that both stool eaters and non-stool eaters were equally easy to house-train seems to discount this hypothesis. Perhaps the most likely predictor for a dog to exhibit this behavior is if he’s a greedy eater: 52% of the stool eaters would steal food off a table. Only 27% of the non–poop eaters showed this lack of impulse control. But even if they were greedy eaters and ate poop, they were still somewhat selective. Over 90% only ate stools one to two days old and 75% only ate stools within the first 24 hours.

Do Commercial Products for Poop-Eating Dogs Work?

Ok, so you finally admit to yourself that your dog eats poop. What can you do? First off, don’t waste your time with the commercial anti-coprophagia agents. Of the 12 on the market at the time— For-Bid®, Nasty-habit®, Copraban®, Deter®,, and Potty Mouth®,  to name a few—none worked in more than 2% of dogs. Many didn’t work in any dogs at all. Even placing chili pepper in the poop didn’t work. Of course, does this really come as a surprise? Clearly, dogs that eat poop don’t care about bad taste. The study also found that you should avoid wasting your breath and energy using punishment.  Yelling or chasing the dog away, electronic collars, and telling dogs to leave-it didn’t work either.

So What Should You Do?

First off, realize that dogs evolved over the last 10,000 + years as scavengers feeding off human trash. So it’s not that surprising that many are non-discerning about what they eat. Also, realize that mother dogs stimulate their puppies to poop by licking their butts and then clean up after them by eating the excrement. So poop eating is virtually in a dog’s DNA. Your best bet is to keep an eye on your dogs when they eliminate and clean up after them promptly. Also, if you have a known offender, make sure to be careful about letting your dog sidle up to you and slip in a wet kiss! At least now you don’t have to worry that your dog’s a freak. He shares this nasty habit with many of his friends.

Also read What to Do if Your Dog Eats Poop.