Coprophagy is the scientific term for the consumption of excrement. This behavior encompasses eating one’s own feces (autocoprophagy), the feces of other individuals of the same species (allocoprophagy), or the feces of other species (heterospecifics). While this act might seem unappealing from a human perspective, it is a common and often necessary behavior observed across a diverse range of animals in the natural world, frequently serving specific biological purposes.
The Role of Coprophagy in Animal Nutrition
For many animal species, consuming feces is a necessary part of their digestive strategy to extract additional nutrients. This is especially true for lagomorphs, a group that includes rabbits, hares, and pikas. These animals practice a specialized form of coprophagy known as cecotrophy, where they produce and re-ingest soft, nutrient-rich pellets called cecotropes. Unlike typical hard fecal pellets, cecotropes are formed in the cecum, a pouch at the junction of the small and large intestines, where microbes ferment plant material.
Cecotropes are coated in mucus, allowing them to pass through the stomach for a second round of digestion. This re-ingestion allows lagomorphs to absorb nutrients not fully digested or absorbed during the initial passage of food. These re-consumed pellets are particularly rich in B vitamins, vitamin K, microbial proteins, and short-chain fatty acids. Animals like guinea pigs, hamsters, chinchillas, and mice also engage in cecotrophy to maximize nutrient extraction from their high-fiber, plant-based diets.
Behavioral and Instinctual Coprophagy
Beyond direct nutritional requirements, coprophagy can also stem from instinctual behaviors or psychological factors in various animals. Domestic dogs, for instance, may exhibit this behavior for several reasons not directly tied to nutrient deficiency. A nursing mother dog often consumes the feces of her puppies to keep the den clean, maintaining a hygienic environment and avoiding attracting predators to her vulnerable young.
For some dogs, coprophagy can be a learned behavior or a response to environmental factors. Boredom, anxiety, or stress can lead dogs to eat feces, particularly if they are left alone for extended periods or are confined. Dogs might also eat feces to seek attention, particularly if they have learned it provokes a strong reaction from owners. It can also be influenced by a scavenging instinct, where feces are seen as an interesting item to investigate.
Health Implications and Human Considerations
While coprophagy serves specific biological functions for many animals, non-selective ingestion of feces can pose health risks. Animals that consume the excrement of other animals, or their own if contaminated, face exposure to intestinal parasites such as giardia and roundworms. Harmful bacteria like E. coli and Salmonella can also be transmitted through fecal matter, potentially leading to gastrointestinal upset, vomiting, or diarrhea.
In humans, coprophagy is not considered a normal behavior and is instead classified as a form of pica, an eating disorder characterized by the persistent ingestion of non-food substances. This behavior is typically associated with underlying medical or neuropsychiatric conditions, including developmental disabilities, mental health conditions like schizophrenia or dementia, or extreme nutritional deficiencies. Human ingestion of feces carries health dangers, including exposure to disease-causing bacteria, viruses, and parasitic worms, which can lead to gastrointestinal issues and other infections.