The Implications of Coprophagy in Multiple Species

1. The Implications of Coprophagy in Multiple Species
Coprophagy is the act of eating feces. This behavior is commonly seen in many
herbivorous rodents as well as some larger mammals. The biological reasons for the
development of this behavior are yet to be fully understood. There are numerous theories that
have been proposed for various species that exhibit coprophagy although extensive studies have
not been conducted in most cases. While the reason for the development of coprophagy is not
clear in all cases some of the nutritional benefits have been recorded as well as environmental
conditions that lead to the exhibition of this behavior. Even though coprophagy has been
observed in both small and large mammals, the technical details and the cycles that are followed
vary between species. We will be looking at some of these cases through the course of this paper.
There are two types of coprophagy, allocoprophagy and autocoprophagy.
Allocoprophagy is the consumption of the excrement of another individual while
autocoprophagy is when an individual ingests their own feces (Well, 2003). Both of these are
seen in nature, particularly among species that are primarily herbivorous but the occurrence of
these behaviors in domestic pets is often disturbing to the owners. There are multiple theories
about what causes coprophagy in domestic animals such as dogs. These range from behavioral
problems to medical issues or abnormalities. Some believe that an imbalanced diet or pancreatic
enzyme deficiency could result in this behavior as the animals attempt to acquire the proper
amount of nutrients. The alternate theory is that the behavior results from operant conditioning.
The dog was punished for eating feces but because of the attention that it received, although
negative, the behavior was reinforced. These animals persist in eating feces so as to get attention
from their owners (Well, 2003)

2. Since this behavior in domestic animals can be unhealthy different theories have
developed suggesting ways to stop or curb this habit. One study that was conducted compared
the effectiveness of two treatments commonly used by the public; the use of spray collars and
sound therapy. These methods are referred to as disruptive stimulants since they work to disrupt
the negative behavior and force the dog’s attention to something else. This particular study
showed that the spray collars had a longer effect on the individuals it was tested on. These dogs
responded to the treatment faster and refrained from coprophagy for a longer period of time after
the trials stopped. This method affects multiple senses, smell, hearing and touch, while the sound
affects only one. It is thought that this may be the reason for the difference in results. By
engaging multiple senses, the animal is able to learn faster and remember the training for a
longer period of time (Well, 2003).
These methods are a direct, physical way to change the dog’s behavior. If the coprophagy
is the result of a dietary or other physiological problem these methods will most likely fail.
Changing the diet to one that is rich in fat, protein and fiber but low in carbohydrates could
reduce the likelihood that the dog will look for an alternate food source and thus eat feces.
Lastly, it is also suggested that flavoring the feces with unpleasant but harmless substances will
aid in curbing the habit through counter-conditioning (Well, 2003).
While coprophagy is seen as a negative behavior in domestic animals there are many wild
animals that depend on coprophagy to survive. Some of these alter their eating habits to include
coprophagy when other food sources are scarce and others practice coprophagy on a daily basis
as a part of their natural metabolic cycles while still others exhibit this behavior only during
certain life stages.

3. Svalbard Reindeer on Spitsbergen are one example of a species that uses coprophagy to
cope with food shortages. Barnacle geese forage in the same habitat as these reindeer for part of
the year. Because of the digestive tract of the goose there is an ample amount of digestible
material in their droppings. Since the reindeer have a more complex gut they are able to
breakdown parts of the plant material that remains in the goose pellets.
While coprophagy was being practiced the animals still exhibited a food preference.
When they are able to forage on plants the reindeer prefer lichens before grasses and both of
these over mosses. This preference persisted into their practice of coprophagy. During a study,
goose droppings that contained different plant material were dispersed in an area. The reindeer
were then observed consuming these pellets and the pellets that were left behind were examined
to determine which plant material they contained. The geese consume grasses and mosses so the
pellets that the reindeer had to choose from contained one of these two materials. It was found
that the pellets containing mosses were refused while the reindeer consumed those containing the
grasses. The cause of this is thought to be the digestibility of the moss pellets. When examined,
the grass pellets had a digestibility that was very similar to that of the actual plant matter. The
preference may also be an adaptation to acquire certain minerals. Selection for potassium over
magnesium and sodium could explain the avoidance of mosses (Loonen et al., 1998).
In addition to this, the area in which this study was conducted had a forage content that
was restricted by the grazing of both the geese and the reindeer. Because of this, it was easy for
reindeer to consume enough feces to meet their energy requirements. In some scenarios where
reindeer would run-off sleeping geese they were able to acquire a substantial amount of energy
from the feces that had accumulated while expending a minimal amount of energy (Loonen et
al., 1998).

4. While the reindeer practice coprophagy to compensate for a shortage of forage material
other herbivores, such as the Degu, rabbit and the rat, use coprophagy in their daily metabolic
cycles. These species reingest a large amount of their feces each day although the cycles vary
between the species. Studies have been conducted investigating the different cycles and reasons
for coprophagy in these species.
The Degu is an herbivorous rodent that consumes abundant but low quality foods. They
are also hindgut fermenters that use microbial fermentation in their cecum to break down some
nutrients. Since this occurs in their hindgut the nutrients cannot be absorbed at this point so the
feces that are produced, which now contain these nutrients, must be reingested so that they can
go through the digestive system a second time and be absorbed. When observed, the Degu
practiced coprophagy during a resting period between feedings and at night. Coprophagy was
also observed when food was scarce. The Degu was also seen chewing each pellet that was
reingested while other species swallow the pellet whole with no chewing (Bozinovic et al., 1998)
As mentioned above, the Degu is a hindgut fermenter. It is believed that coprophagy in
this class of animals allows food to pass through the digestive system twice which results in the
possibility for increased absorption of nutrients (Lewin, 2001). The chewing of the pellet that is
observed in the Degu suggests that the fermentation did result in the release of more nutrients.
By practicing coprophagy during times of rest between feedings the Degu prevents the feces
from competing with food for time and space in the digestive system. While the Degu practices
coprophagy during these resting times it has been noted that the rate of coprophagic behavior is
increased in times when food is scarce and during the reproductive season. This is another
indication that nutrients are gained through this behavior which will provide the animal with
more energy to survive the stress successfully (Bozinovic et al., 1998).

5. The Degu is one of many rodents that practice coprophagy but the behavior is also seen
in numerous lagomorphs such as hares, rabbits and pika. In these species the pattern of feces
consumption varies from that seen in the Degu. Instead of consuming feces during the night
these species discharge pellets from the cecum during short periods in the morning and evening.
Each pellet is swallowed whole, contrary to the chewing behavior seen in the Degu (Bozinovik et
al., 1998).
Another example of a rodent practicing coprophagy is the Nutria. According to studies
conducted with this species it was found that coprophagy increases the digestibility of acid
detergent fiber and crude protein. This allows these animals and other rodents similar to them to
survive on low protein diets. In this case, feces were chewed before being consumed and the
individuals had a specific posture that they assumed before each act of coprophagy. The cycle of
coprophagic behavior involves vigorous eating and drinking after sunset followed by coprophagy
from midnight to noon (Sakaguchi, 1998).
Unlike some other species, the coprophagy cycles differ with age in the Nutria. Adult
animals spend much more time in this behavior then the young. Adult nutrias also began this
behavior before sunset without a visible cue. Another attribute unique to the Nutria is the
concentration of bacteria on a specific region of their hard feces while soft feces show distinct
compositional differences from these hard feces. The soft feces also contain more bacteria then
the hard feces. These feces are comparable to the rumen fluid of other animals and thus allow the
nutrias to absorb more protein while having the potential to release more amino acids into the
system (Sakaguchi, 1998).
Another species that practices coprophagy is the American Beaver. Reingestion in this
species begins at a young age, approximately ten days after birth, and is refined to a more

6. proficient process by the time the animal is twenty days old. In this species feeding and
defecation occur mostly during the early evening with the animal sleeping till mid-morning
before practicing coprophagy. This behavior was the strongest at mid-day and slowed in the
afternoon, alternating with sleep until feeding resumes in the evening (Buech, 1984).
The digestive system of the beaver is believed to process material in the following way,
food is partially digested as it passes through the stomach and small intestine. It is then passed to
the caecum which contains microorganisms that digest cellulose. After this, part of this material
is passed to the colon and reingested during the middle of the next day. This allows the small
intestine to absorb nutrients that are released by the caecal microbes (Buech, 1984).
Although coprophagy can function solely to recover nutrients it may also serve other
physiological functions. The digestive system of some young animals is dependent upon gut
flora that is obtained by consuming the feces of the parent animals (Lewin, 2001). In the case of
rats, coprophagy functions to recover compounds necessary to the proper functioning of their
biological systems (Ikeda et al., 2003). In order for the digestive systems of some animals to
become fully functional and able to handle the food consumed they must obtain particular gut
flora. This flora is obtained by consuming the feces of a parent which contain small samples of
these microbial compounds. The young can then retain this flora in their gut which allows them
to breakdown their food properly (Lewin, 2001).
In addition to this, rats produce two different types of feces, hydrous and normal. The
hydrous feces are those that are consumed when the animals practice coprophagy. The normal
feces are allowed to pass without being reingested. After examining the different types of feces it
was found that the hydrous feces contain significantly more sodium and potassium then the
normal variety as well as higher levels of protein, cyanocobalamin and folic acid. The sodium

7. and potassium cations have been shown to play a key role in the sodium-potassium pump that
functions to aid intestinal absorption and transport nutrients in the cells. These compounds are
also required for proper growth. If coprophagy is restricted in these animals there is not an affect
on food intake but on the absorption and use of nutrients in the food that is consumed. This,
therefore, results in vitamin deficiencies and reduced growth in the animals (Ikeda et al. 2003).
Rabbits practice coprophagy in a manner similar to that seen in rats. They also produce
two different types of feces, soft and hard, with the soft being immediately reingested (Boag et
al., 2004). While there is an emphasis on the reingestion of the soft feces the rabbits also reingest
the hard feces regularly. This results in a mix of isotopes from the dietary material in the stomach
that has been diluted by the consumption of the feces. The difference between the isotopic
content of the stomach and the fecal material indicates that the feces may have a role in
separating isotopes in these animals and thus altering their absorption in these animals (Boag et
al., 2004).
Although many animals practice coprophagy as a part of their metabolic cycles, this
behavior also results from some health problems such as exocrine pancreatic insufficiency. This
illness is common in many domestic animals as well as pigeons. An individual afflicted with this
illness experiences a loss of tubulo-acinar tissue due to inflammation or atrophy. This loss results
in an insufficient production and secretion of digestive enzymes and malabsorption. This
decreased absorption can lead to deficiencies in many vitamins, the effects of which depends on
the species that is ill and how the different vitamins are used by their system (Amann et al.,
2006).
Coprophagy is a behavior that is common among many wild animals although the basis
for this act varies. Many herbivores exhibit this behavior as a way to obtain more nutrients from

8. poor quality foods or to survive in harsh climates lacking the proper amount of forage. Some of
the species practicing coprophagy, such as many of the rodents, have digestive systems that are
modified specifically for coprophagy. These systems expel feces in different forms depending on
their content and potential use as a food source. Often times, one type of feces that is expelled
will be continuously consumed while the other type is discarded as waste.
While coprophagy is common in many herbivores it can also be observed in some
domestic animals such as dogs and other wild animals that must acquire gut flora from their
parent. This behavior is disturbing in the domestic breeds since it may lead to illness if the
individual consumes infested feces. Because of this many owners seek treatments to halt this
behavior and redirect the animal’s attention. The conditions that result in this behavior among
domestics is often similar to that seen when some wild animals practice this behavior such as
when they experience food stress.
Coprophagy has many biological and physiological functions. These range from the
obtainment of nutrients to the acquisition of particular minerals or gut flora. The behavior is
natural and serves a specific in each species that practices it. While this behavior is crucial to the
proper survival and growth of many species more studies need to be conducted to uncover all of
the implications of this behavior.

9. Works Cited

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2006. Exocrine Pancreatic Insufficiency in Pigeons. Avian Pathology. 35: 58-62.

Boag, B. and Hartley, G. and Neilson, R. 2005. Temporal Host-parasite Relationships of the
Wild Rabbit, Oryctolagus cuniculus as Revealed by Stable Isotope Analyses. Parasitology. 131:
279-285.

Bozinovic, Francisco and Kenagy, G.J. and Veloso, Claudio. 1999. Daily Rhythms of Food
Intake and Feces Reingestion in the Degu, an Herbivorous Chilean Rodent: Optimizing
Digestion through Coprophagy. Physiological and Biochemical Zoology. 72: 78-86.

Buech, Richard. 1984. Ontogeny and Diurnal Cycle of Fecal Reingestion in the North American
Beaver. Journal of Mammalogy. 65: 347-350.

Hirakawa, Hirofumi. 2002. Supplement: Coprophagy in Leporids and Other Mammalian
Herbivores. Mammal Rev. 32: 150-152.

Ikeda, S. and Ito, S. and Kurihara, Y. and Sukemori, S. 2003. Amino Acid, Mineral and Vitamin
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Anim. Nutr. 87: 213-220.

Lewin, Ralph. 2001. More on Merde. Perspectives in Biology and Medicine. 44: 594-607.

Loonen, Maarten and van der Wal, Rene. 1998. Goose Droppings as Food for Reindeer.
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Sakaguchi, E. and Takahashi, T. 1998. Behaviors and Nutritional Importance of Coprophagy in
Captive Adult and Young Nutrias. J Comp Physiol B. 168: 281-288.

Wells, D.L. 2003. Comparison of Two Treatments for Preventing Dogs Eating Their Own
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