Why do some dogs eat human feces?

Dogs eating poop

Scatophagia is a fairly common form of feeding in many animals. In dogs, this behavior is believed to date back to the Paleolithic Age, when they began to associate with humans. A very “nutritious” food was thus easily accessible to them: human excrement.

An abundant source of food

Consuming their own feces or those of other animals is a fairly common behavior in dogs: 1 in 400 would be affected. Among the factors pushing dogs to scatophagia (or coprophagia), we find medical causes such as intestinal problem, gastritis or even enzyme deficiency. It can also be a dietary problem, when the dog eats low-end, hard-to-digest food daily.

There is also a possible behavioral disorder linked to boredom, depression, stress or a developmental disorder. If these explanations seem valid, they do not however provide any information on the reasons pushing some dogs to appreciate human excrement. On the other hand, wolves also indulge in coprophagia, but they eat little or no human feces.

Behavior specialists Ray and Lorna Coppinger have looked into this behavior. They explained in their book A New Understanding of Canine Origin, Behavior, and Evolution (2002) that garbage played an essential role in the domestication of the dog.

Recall that the evolution of dogs from wolves dates back to the Paleolithic (from – 40,000 to – 9500). The wolves would then have distanced themselves from the nomadic groups of hunter-gatherers. They then joined the first sedentary human groups. When humans became sedentary, garbage dumps appeared. Thus, the wolves had access to an abundance of food. However, the most tolerant of humans would thus have gained an advantage over other animals and this transition ultimately favored their taming.

An important source of nutrients

However, the first human settlements were too small to produce enough rubbish for the growing numbers of wolves. In his study published in the journal Psychology Today, anthropozoologist Hal Herzog explained that the feces of our ancestors were shown to be an important source of nutrients at the time. We should also mention a 2018 study published on stray dogs. The results indicated that human feces contributed 21% to their diet. In 2010, another study compared the diet of domestic dogs (Canis familiaris) with that of the Abyssinian wolf (Canis simensis). The results showed that the diet of domestic dogs consisted of 20.7% human feces, while Abyssinian wolves mostly fed on small rodents.