Unusual eating habits

Dogs and cats sometimes eat non-food items, which can produce life-threatening blockages in the animal’s intestines. A form of this behavior is stool eating (either their own of that of another animal). While not necessarily dangerous to the animal, it is often unacceptable to the owner.

Eating non-food items is called pica, and stool-eating is called coprophagy. Because pica and coprophagy are behaviors which are not well understood, stopping them may require assistance from an animal behavior professional who works individually with owners and their animals.

Causes of pica and coprophagy

The causes of pica (eating non-food items) and coprophagy (stool eating) are unknown but the following causes are possible.

  • Attention-getting: If showing these behaviors results in some type of social interaction between the animal and the owner (even a scolding) then the behavior may be reinforced and occur more frequently.
  • Parental behavior: Coprophagy may be carried over from the normal parental behavior of ingesting the waste of young offspring. Some experts believe coprophagy occurs more often in animals who live in relatively barren environments — who may be frequently confined to small areas and received limited attention from their owners.
  • Learned behavior: Coprophagy may be seen more often in dogs who tend to be highly motivated by food. It is possible that a dog may learn this behavior from another dog. Coprophagy is fairly common in dogs but is rarely seen in cats, for reasons unknown.
  • Lack of nutrients: Both pica and coprophagy may be attempts to obtain a necessary nutrient lacking in the diet, although no nutritional studies have ever substantiated this idea.
  • Boredom or anxiety: These behaviors may also be frustration or anxiety related and occur when the animal is “bored,” anxious or afraid. It is possible the behaviors begin as play, as the animal investigates and chews on the objects, and subsequently for unknown reasons begins to eat or ingest them. Suckling of objects may occur in animals who were weaned too young or prevented from nursing for some other reason.
Preventing pica

This can be a more serious problem because items such as rubber bands, socks, rocks, and string can severely damage or block an animal’s intestines. In some instances, the items must be surgically removed. The chances of resolving this type of problem successfully will probably be greater if the reason for the behavior can be determined. Unfortunately, this will often not be possible, as the behavior is poorly understood. Making the objects the animal is eating taste unpleasant with some of the substances mentioned previously may be helpful. Owners may need to either prevent the animal’s access to the items, and/or be very vigilant about putting socks and other such items out of reach. If the animal is very food oriented, it may be possible to change to a low-calorie or high-fiber diet to allow him to eat more food, more often, which may decrease the behavior. Check with your veterinarian before changing diets.

Pica can be an attention-getting behavior, play behavior or a frustration or anxiety-relieving behavior. If anxiety or frustration is involved, the reason for these reactions must be identified and the behavior changes using behavior modification techniques.  Cats commonly play with string, rubber bands, and tinsel and ultimately ingest them. Owners need to keep these out of reach and provide a selection of appropriate toys.

Because pica can potentially be a life-threatening behavior problem, it may be advisable to consult both your veterinarian and an animal behavior professional for help.

Preventing coprophagy

Because the causes of the problem are not well understood, no treatments which are consistently successful are available. A commercial product, 4-BID, available from veterinarians, when put on a dog’s food supposedly produces a stool with an unpleasant taste. It has been said the same result can be achieved by putting MSG (mono-sodium-glutamate, a food additive) on the food. Based on owners’ reports, both of these products appear to work in some cases, but are often ineffective. Before using either of these products, check with your veterinarian. The stools can also be given an aversive taste by sprinkling them directly with either cayenne pepper or a commercial product called Bitter Apple. For this method to be effective, every stool the animal has access to for a length of time must be treated in order for him to learn that eating stools results in unpleasant consequences. It is obviously difficult for most owners to watch their dogs each and every time they defecate. In addition, it may be possible for some dogs to discriminate by odor which stools have been treated and which have not. Interactive punishment (punishment which comes from the owner) is usually not effective because 1) attempts at punishment, such as a verbal scolding, may be interpreted by the dog as attention and/or 2) many dogs learn not to show the behavior when their owners are present, but will do so when owners are absent. The simplest solution may simply be to clean the yard daily in order to minimize the dog’s opportunity for coprophagy.

Any type of environmental “booby-traps” to stop a dog from eating cat feces from the litter box must be attempted with caution. Anything which frightens a dog away from a litter box is also likely to frighten the cat away as well. It is much better to install a baby-gate in front of the litter box area as a cat will have no trouble jumping over it while most dogs will not make the attempt. Alternatively the box can be placed in a closet or room where the door can be wedged open from both sides (so the cat cannot be trapped in or out) a small enough distance to allow the cat access but not the dog.

Health risks: In a dry climate, parasites are not nearly the problem as in other parts of the country. A dog who is parasite free and is eating only his own stools cannot be infected with parasites by doing so. If a dog is eating the stools of another dog who has parasites, it may be possible, although still unlikely, for the dog to become infected. Some parasites, such as giardia, cause diarrhea, and most coprophagic dogs ingest only formed stools. In addition, there is a delay period before the parasites in the stools can re-infect another animal. Finally, most parasites require intermediate hosts (they must pass through the body of another species such as a flea) before they can re-infect another dog or cat. Thus, dogs are much more likely to become infected with parasites through fleas and killing and/or eating birds and rodents than by coprophagy. Most parasites are also species-specific, meaning that dogs cannot be infected by eating cat stools. Although some owners may think it unpleasant, health risks to humans from being licked in the face by a coprophagic dog are minimal. For more information, contact your veterinarian.

Written by Suzanne Hetts, Ph.D. Certified Applied Animal Behaviorist, Denver Dumb Friends League (Humane Society of Denver). If this material is reproduced the author and DDFL must be credited.

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