Coprophagia

# Overview
Coprophagia is the consumption of feces, from the Greek copros (feces) and phagein (eat).  Many animal species have evolved to practice coprophagia; other
species do not normally consume feces but may do so under unusual conditions.  Only in rare cases is it practiced by humans.

# Evolved coprophagia
Coprophagous insects consume and redigest the feces of large animals; these feces contain substantial amounts of semi-digested food. (Herbivore digestive systems are especially inefficient.)  The most famous feces-eating insect is dung-beetle and the most ubiquitous being the fly.
Pigs are most commonly associated with eating not only their own dung, but those of other animals and humans. In parts of the third world, where village dwellers excrete in the open, pigs are known to eat it.
Rabbits, cavies (guinea pigs) and related species do not have the complicated ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft caecal pellets of partially digested food are excreted and generally consumed immediately. They also produce normal droppings, which are not eaten.
Young elephants, panda bears, koala bears and hippos eat the feces of their mother to obtain the necessary bacteria for the proper digestion of the vegetation found on the savannah and in the jungle.  When they are born, their intestines do not contain these bacteria (they are completely sterile).  Without them, these youngs would be unable to get any nutritional value from plants.
Gorillas eat their own feces and the feces of other gorillas.
Hamsters eat their own droppings; this is thought to be a source of vitamins B and K, produced by bacteria in the gut. Apes have been observed eating horse feces for the salt. Monkeys have been observed to eat elephant feces.

# Theories on dogs
Coprophagia is a behavior sometimes observed by dog owners. Hofmeister, Cumming, and Dhein (2001) wrote that this behavior in dogs has not been well-researched, and are currently preparing a study.  In a preliminary paper, they write that there are various hypotheses for this, although none have been proven:
- To get attention from their owners.
- From anxiety, stress,  or having been punished for bad behaviors.
- They had been punished for having defecated in the past, and attempt to clean up out of fear to be punished again.
- From boredom.
- In an attempt to clean up in crowded conditions.
- When dogs observe their owners picking up feces, and imitate this behavior (allelomimetic behavior). This is highly improbable because the behaviour has also been observed in environments where owners never picked up the dog's (or other) feces.
- Because puppies taste everything and discover that feces are edible and, perhaps, tasty, especially when fed a high fat content diet.
- Because dogs are, by nature, scavengers, and this is within the range of scavenger behavior.
- To prevent the scent from attracting predators, especially mother dogs eating their offspring's feces.
- Because the texture and temperature of fresh feces approximates that of regurgitated food, which is how canine mothers in the wild would provide solid food.
- Because of the protein content of the feces (particularly cat feces), or over-feeding, leading to large concentrations of undigested matter in the feces.
- Due to assorted health problems, including:
Pancreatitis
Intestinal infections
Food allergies, creating mal-absorption
- Pancreatitis
- Intestinal infections
- Food allergies, creating mal-absorption
- Because they are hungry, such as when eating routines are changed, food is withheld, or nutrients are not properly absorbed.
- Carnivores may sometimes eat or roll in the feces of their prey to ingest and exude scents which camouflage their own.
The most obvious reason--desperate hunger--is rarely considered.
Some veterinarians recommend putting meat tenderizer in dogfood, since this makes the feces taste excessively bad to dogs.  Several companies produce food additives that can also be added to the animal's food to make feces taste bad.
Due to the attraction of dogs to their feces, a popular Chinese idiom goes "A dog cannot change its habit of eating feces", which usually refers to a habit that is hard to correct.

# Humans
Coprophagia is extremely uncommon in humans.  It is generally thought to be the result of the paraphilia known as coprophilia, although it is only diagnosable in extreme cases where it disturbs one's functioning. From the medical literature, coprophagia has been observed in a small number of patients with dementia, schizophrenia and depression. Consuming other people's feces carries the risk of contracting diseases spread through fecal matter, such as hepatitis.  Hepatitis A, Hepatitis E, pneumonia, and influenza vaccinations are generally recommended for those who engage in this practice.  Consuming one's own feces potentially involves risk, as the bowel bacteria and eggs of parasitic worms are not safe to ingest. Similar risk can apply to related sexual practices, such as anilingus or inserting an object into the mouth that has recently been in the anus (see ass to mouth). The practice of coprophagia in humans is also depicted in a handful of motion pictures. For examples see section Coprophagia in motion pictures below.
Lewin (2001) reports that "... consumption of fresh, warm camel feces has been recommended by Bedouins as a remedy for bacterial dysentery; its efficacy (probably attributable to the antibiotic subtilisin from Bacillus subtilis) was confirmed by German soldiers in Africa during World War II."
Coprophagia is also depicted in porn sometimes.