Journal Scan: Whats the scoop on dogs eating poop?

January 9, 2019
Hilal Dogan, BVSc, CCTP
Hilal Dogan, BVSc, CCTP

Frequent Fetch dvm360 speaker Dr. Hilal Dogan practices medicine in Denver, Colorado. She started the Veterinary Confessionals Project as a senior veterinary student at Massey University in New Zealand.

A recent study shows that your dog eating its own poop isnt weird. In fact, the behavior probably comes from their wolf ancestors.

If only dogs had an instinct to clean up their accidents like this instead of some who choose to eat the evidence. (dwclasspics/adobe.stock.com)

Whenever I see dogs eat poop, I'm mortified. In the aftermath of this horrific sighting, I won't kiss my dog, let him near my face or lick my hand. This is actually one of the reasons I don't like when dogs lick my face, period. If they do sneak a lick in, I will run to the bathroom with the urgency of someone who caught an unfortunate case of Delhi belly and scrub my face clean. Call me paranoid, or uptight, but don't think this means I love dogs any less. However, according to this study, coprophagy is a serious issue when it comes to the human-animal bond. While there seems to be no clinically established abnormalities (such as gastrointestinal upset, nutritional deficiency or compulsive disorder) associated with coprophagy, owners are often disturbed when they witness their dog eating its own feces. This revulsion towards coprophagy may possess the ability to destroy the human-animal bond to the extent that owners request euthanasia.

What they did

The study evaluates the external factors associated with coprophagy in dogs, such as sex, age, breed, yard space available, ease of housetraining, type of food given, type of eater (finicky, greedy, normal) and more. Conspecific coprophagy-eating the stool of one's own species-was especially analyzed. The efficacy of behavioral modifications underwent evaluation as well as 11 products marketed for treating coprophagy.

The study used two internet surveys to gather data. One survey compared coprophagic dogs with non-coprophagic dogs, while the other encouraged owners of coprophagic dogs to learn about the coprophagy traits and treatment. The first survey received 1,552 responses and defined coprophagy as owners having seen their dog eating stool at least six times. Yielding 1,475 responses, the second survey defined coprophagy as seeing the dog eating stool more than 10 times and doing so at least once a month. Chi squares, Fisher's exact tests and logistic regression were used for statistical significance testing. The study also attempted to identify the historic cause of the behavior, specifically if it stems from an innate behavioral predisposition, possibly from wolf ancestors who ate feces to keep their den clean. Doing so reduced wolves' risk of parasitic infection from the feces had it just been left in the den.

What they found

From the first survey:

In contrasting coprophagic dogs with non-coprophagic dogs, no pattern was found in regard to distribution among sex or neuter categories, age, diet, ease of house training, lack of normal mothering or association with compulsive behavior. However, several factors did reveal significant differences between coprophagic and non-coprophagic dogs. The survey found that coprophagic dogs are more likely to be greedy eaters and live in multi-dog households, where larger quantities of stools could be found. The survey also showed that the consumption of dirt and cat stools correlate with coprophagy and breed, with terriers and hounds being most coprophagic.

From the second survey:

Eighty-five percent of dogs reported eating stools no more than two days old (fresh stools). Eliminating coprophagia with behavioral modifications reported a success rate of 1 to 4%. The survey didn't inquire as to whether or not these behavioral modification techniques were conducted by a canine behavior specialist or the respondent themselves. The reported success rates of food additives and tablets marketed to stop coprophagy ranged from 0 to 2%. The survey did not ask if the instructions that came with products were properly utilized.

The study concludes that coprophagy is not a result of abnormal behavior, as outlined in the first survey. Instead, it's more likely a result of ancestral wolf-like behavior-an adaptive behavioral defense against intestinal parasites of wolves living in nature, where consuming feces left in the den is the only option to remove said parasites. For it was determined that the most frequently reported intestinal parasites in wolf feces do not develop into infective form for at least two days. This hypothesis that some dogs may be displaying wolf-like coprophagy behavior is parallel to other wolf-like behavior in dogs. In fact, the finding that being a “greedy eater” is the strongest differentiator being a coprophagic dog would seem to support the wolf origin hypothesis as most would associate greedy eating as a wolf characteristic.

So the next time a client complains about their dog eating poop, tell them their dog is a wolf hybrid, and it might make them feel better (maybe even cooler). Who knows, it may shift their perspective. Instead of viewing coprophagy as disgusting, they may start to think their doggo is awesome because they are in touch with their ancestral wolf roots.

Hart BL, Hart LA, Thigpen AP, et al. The paradox of canine conspecific coprophagy. Vet Med Sci 2018;4:106-114.

Read the article here.