Regardless of how natural the behavior may be, dog owners are understandably horrified to see their pets eating poop. Not only does it seem undeniably unhealthy, but there is also no concrete scientific explanation for why a trained, socialized pet would do such a thing.
Not As Unhealthy As You Think
Before exploring potential answers, it’s important for dog owners to know that coprophagia (the term for an animal eating poop) is usually not dangerous at all.
Nicholas Dodman, veterinary behaviorist at Tufts University, told National Geographic in 2015 that your dog’s health will not suffer even if the poop belongs to another dog or another kind of animal altogether.
“Poop is poop," he said.
Rabbits and chimps are among the numerous other animals that eat their own poop, mostly because it contains beneficial nutrients from undigested food. If they didn’t eat the poop, these nutrients would go to waste. You could say it’s their digestive system’s fault for not breaking down the food enough the first time.
Dogs Most Likely Inherited The Habit
The reason why dogs eat their own poop, however, isn’t so clear. One theory is that it’s a behavior they learned from their mothers, who lick infant puppies in their genital regions to clean off urine and poop.
“[The mother] doesn't have opposable thumbs and tissues. She can't pick it up and throw it out, so she just licks it up and disposes of it that way," Dodman says. It doesn't make mom sick, he says, noting that puppy feces contains ‘friendly bacteria.’
A new study conducted at the Center for Animal Behavior at the University of California at Davis suggests that it’s not their mothers but their wild ancestors who passed down coprophagia.
Researchers led by veterinarian Benjamin Hart surveyed more than 3,000 dog owners and found that coprophagia is a tendency of virtually all types of dogs. Factors like age, breed, diet, or training capacity apparently did not make a dog any more or less likely to eat poop.
With this observation in mind, the researchers proposed that dogs inherited coprophagia from wolves.
Why Wolves Ate Poop
These ancient animals are said to have eaten the poop of sick or older pack members who had defecated inside the den. They weren’t looking for health benefits; they just wanted to clean up. The habit continued once the wolves realized it could protect them from intestinal parasites that would have otherwise flourished from poop that had been left alone.
This theory is supported by the fact that ancient wolves are also allegedly responsible for a dog’s refusal to poop in the same place it lives or sleeps.
Still, some experts believe that dogs eat their poop for the same reason as rabbits and chimps. While dogs might not have the downsized guts and high metabolisms of rabbits, their diets are largely made up of nutrients that don’t always get completely digested, like fats and protein.
What Concerned Pet Parents Can Do
The researchers are now examining recent clinical trials involving new products designed to stop dogs from eating poop.
Pet parents who want to discourage the habit might want to try rewards-based training or a product that you can add to poop to make it taste even worse. But the first step should be a visit to the vet in order to make sure your dog’s coprophagia isn’t a sign that it isn’t eating well.