I love my dog but sometimes she does things that gross me out a bit. She has a tendency to find dead insects, mice or birds to roll in. Or sometimes she gets a bit too close when she says hello to her own kind. These habits are exactly why I am hesitant to share my ice cream with her. However, I am grateful that her habits are not as bad as they could be. For example, some dog owners have to deal with their dogs engaging in coprophagy or the consumption of feces.
Why would a dog eat poop?
Believe it or not, there might be rational explanations to explain this odd – perhaps disgusting – behavior. There is unlikely to be a single explanation as to why any pet would consume feces...
We often strive to teach our pets certain behaviors and we may also accidentally teach or reinforce a behavior we do not want. The truth is, we tend to misunderstand how our dogs view the world: with poor memory. A study suggests that if punishments or rewards do not occur within a half a second, you might as well not bother. You walk in the door to find that your dog has chewed your favorite pair of sneakers. Anger is a reasonable first reaction but scolding your dog in this moment could lead to a misunderstanding. The issue is your dog chewed your sneakers over an hour ago, ancient history to a dog. From your dog's perspective, your pet sees you and is punished. If this pattern were to repeat, you may accidentally teach your dog that your return means punishment. The same misunderstanding can happen over poop. A strong reaction over your dog getting close to poop or punishing your dog for pooping in the house could accidentally encourage coprophagy. If you're interested, cracked.com has a great list describing the ways we are accidentally ruining our pets.
A side-effect of domestication
At the same time, niave, untrained puppies can also be seen consuming human excrement suggesting coprophagy could be a side-effect of this domestication of dogs. Current evidence suggests the floppy-eared, cuddly dogs we know and love today evolved from the gray wolf 130,000 years ago. Gray wolves that started to hang around humans eventually learned they could get food from scraps – and perhaps poop – from humans. In fact, the scavenging of nutrients by dogs from the feces of other animals like cats and rabbits has been well-documented and thought to be an attempt to take advantage of these discarded resources. As they say, one animal's trash is another resourceful dog's essential vitamins and nutrients, right?
A warning sign for a medical problem
Eating poop could be a sign of a medical condition like a malabsoprtion snydrome. These syndromes can be caused by small intestine disease or an insufficiency of the pancreas that produces most of the enzymes needed for proper digestion. If these enzymes and nutrients are not absorbed during digestion, they are excreted in the feces. Similar to eating other animals feces above, eating their own feces may be an attempt by these sick dogs to successfully extract nutrients from their food by trying again.
A way to replenish your gut microbe community
The medical community is starting to appreciate how important the microbes in our gut are for our health (See Chris' Mutualism of the Month post on the human microbiome for more details). For example, good microbes in our bodies may block bad microbes from colonizing our bodies. Some evidence also suggests these microbes positively affect how our immune system functions and even influence the way we think. This growing body of work may soon lead to our gut microbiome to be considered its own organ that we can treat when get sick.
Some people suffering from chronic diarrhea are already having success with treatments that target the gut microbiome. Individuals suffering from an infection by Clostridium difficile, a nasty toxin-producing bacterium that takes over the gut if given the chance, may find relief through replenishing their gut with a healthy collection of microbes from someone else. This procedure called fecal transplants can be performed during colonoscopies, delivered via enemas or even in the form of a pill. It may be a hard pill to swallow but you may find yourself engaging in coprophagy if you suffer from chronic diarrhea.
Animals may self-medicate stomach issues. For example, dogs are already well-known to eat grass to settle their stomach or induce vomiting. Dogs that are not feeling well or have an upset stomach may also eat feces for the same reason; an instinctive way to replenish their gut microbes and receive a fecal transplant. The biggest difference is that eating grass is a little less disgusting.
So, could eating poop be a good thing?
It is certainly a hard sell to say that eating poop is a good thing. It is certainly not always a good thing. As discussed above, eating poop could be beneficial as a last resort to acquire essential nutrients or replenish microbes. The same kind of behavior can be seen with humans; drinking your own urine could be the difference between life and death if you find yourself in a survival siutation. However, the practice is typically not encouraged. For example, the US army does not recommend that strategy at all.
At the end of the day, animals seem to have some pretty remarkable instincts and we may just be catching up.
What do you think? Plausible or just too far-fetched to believe?