Are Dogs Omnivores Or Carnivores?

by admin on April 29, 2011

Two philosophies

That seems to be the fundamental question that separates the two raw feeding camps. One group call themselves “prey model” feeders and insist that dogs are carnivores that should eat little other than meat. Its adherents boast about feeding no plant matter to their dogs. On the other side there are the BARF (bones and raw food) feeders, who feed a very large variety of foods, some of which have no historical or evolutionary basis in basic dog biology.

You’d never know it by the way the two camps squabble with each other over the details, but there is more agreement than disagreement between them. Both philosophies contain some truth and some falsehood.

Dogs are Facultative Carnivores

Dogs actually belong to a category of meat eaters called “facultative carnivores”, which is so close in functional behavior to the are dogs omnivore category as to be hardly distinguishable. Here’s what Wikipedia has to say about the term:

“Animals that depend solely on animal flesh for their nutrient requirements are considered obligate carnivores while those that also consume non-animal food are considered facultative carnivores. Omnivores also consume both animal and non-animal food, and apart from the more general definition, there is no clearly defined ratio of plant to animal material that would distinguish a facultative carnivore from an omnivore, or an omnivore from a facultative herbivore, for that matter.”

“Facultative” means contingent, optional, or not required. In other words, their primary food is meat or prey but they are capable of surviving without them, perhaps not indefinitely but for long periods.

Biases about the human dietetic character cause confusion

Unfortunately, when people develop or adopt a new ideology, they usually bring their existing belief systems and biased assumptions with them. Among raw feeders, the belief system that human beings are either omnivores or carnivores tends to determine which side of the canine omnivore vs. carnivore debate they end up on. Determining the truth about human dietary requirements is a simple matter of examining the evidence objectively, which reveals that we are neither carnivores NOR omnivores.  Humans belong to a class of plant eaters called “frugivores”, or fruit-eaters, like all of our primate relatives.  This is known with as much certainty as any other basic fact of science.

One might rightly wonder what any of this has to do with dog nutrition.  It has nothing to do with it, but, unfortunately, it does end up influencing the thinking of even high profile leaders within the raw feeding world. After all, if they accept the idea that dogs are omnivores, it becomes uncomfortably obvious that humans are not. To keep intact their cherished belief that humans are biologically suited to eat anything that will fit into our mouths, they declare that dogs are carnivores and use this to account for the anatomical differences between us and them.  Then, based on this belief, they feed nothing but meat to their animals.  On one raw feeding forum recently, the moderator commented that his dog had never been fed plant matter in her 11-year life.  He went on to say that she was in great health except for being diagnosed with cancer of the liver.  Liver cancer does not develop overnight and although there are other possible causes for it (like certain pharmaceutical drugs), what a dog is fed would certainly be the primary cause.

What’s wrong with ‘BARF’?

Although BARF feeders contend correctly that dogs are essentially omnivorous, they have some mistaken ideas within their philosophy as well. They tend to over-analyze the nutritional needs of dogs, and they make the mistake of thinking they can make up for the hazards of feeding the products of modern animal agriculture by feeding supplements and indigestible non-foods like oils, dairy products and garlic.  They typically try to replicate commercial processed food by combining many different types of foods together in the same meal.

The lines between classifications are not definite

A problem on both sides is that people like to make things too black and white. The line between taxonomy classifications is not that clear cut. In every category there is a range of species and the foods on which they thrive. Within carnivora, there are species that thrive SOLELY on prey animals and there are others for whom prey animals are only the primary but not exclusive source of food.

For example, cats are often called “obligate” carnivores and it’s true that they would not thrive or even survive without regular fresh kills. Cats have practically no need for plant foods. Dogs, on the other hand, can survive long periods without a fresh kill, and they can do particularly well if other foods are available. One study of Yellowstone wolves found that their consumption of prey dropped by 25% during the summer months when other foods (fruits, primarily) were accessible. The researchers also followed one lone wolf that did not get fresh meat for a 10-week period one winter. He lived on previously scavenged carcasses (dried bones and hide), which means he ate practically nothing at all. There are other cases of wolves going even longer without food.

Is fasting a normal part of the canine experience?

It could be debated whether fasting due to food scarcity has been common enough in the history of dogs to become a biological requirement. Minimally, the accumulated body of evidence would suggest that canids adapted a need to eat much more sparingly than is commonly thought, and certainly far less than what domestic dogs are typically fed. Even when the wolves in the above study had abundant food, they only ate fresh prey every 2-3 days on average, and it should be recognized that the foods they were eating were extremely clean compared to what we raw feeders are forced to feed our dogs. What all of this tells us is that the optimal diet of dogs involves getting fresh meat anywhere from twice a week to perhaps as infrequently as a few times per month. The natural ability of canids to do well on foods other than prey for long periods would also account for the anecdotes we hear about vegan dogs doing surprisingly well, especially compared to their kibble-fed counterparts. If it was true that dogs could only thrive on daily meat feedings, as “prey model” feeders claim, this could not be the case.

Rotational Mono-feeding solves the overfeeding problem

Overfeeding seems to be the biggest mistake that dog owners make, regardless of what foods they feed.  Fruits and other easily digested plant foods offer a digestive break from the fatty, unbalanced, domestically raised animals that are fed by prey model feeders on a too regular basis. The consequence is overall toxemia, wherein the body’s tissues, bloodstream and organs become saturated and compromised by uneliminated waste. The same thing happens to BARF-fed dogs, because of the complicated nature of the diet which makes digestion more difficult and causes much of the food to become unusable waste.

When dogs are young, they may do exceedingly well on any diet, including kibble. It often happens, however, that disease shows up when a dog approaches mid-life. This is when owners need to re-evaluate what they’re feeding. If they are very emotionally invested in one philosophy over another, which most are, they will not be able to do this objectively. Assuming incorrectly that they’re already doing everything right means that rather than seeking out the real causes of disease (which are almost always dietary in origin), raw feeders are as likely as kibble feeders to blame other factors, like genetics, previous vaccination and nutrient deficiency, and resign themselves to disease maintenance or symptom ‘management’.

Diet is the #1 determining factor in health

Dogs do have their share of problems caused by breeding and vaccination but it is not helpful to make these assumptions without considering more probable causes which may be controllable, such as diet. Nutrient deficiency, for example, is almost never dietary in origin but has its roots in the body’s inability to utilize the nutrients coming in, because of pre-existing disease, which is best dealt with via removal of cause. Nutritional supplementation might be perceived as removal of cause but it is not, because fractionated supplements do not function the same as nutrients do when they are eaten in their natural context, as part of a whole food.

In dog nutrition, fruits and veggies are not created equal

The bottom line is that there may be better, more objective information to guide us than simple taxonomy classifications. It is difficult to reconcile the plant-eating behaviors that have been observed in wolves with the idea that domestic dogs should be fed only meat. Perhaps putting all plants in the same category doesn’t serve us either. Wolves don’t generally eat very starchy or cellulose-rich foods and dog owners have noted that, when fed, these foods generally remain intact when they exit in the feces. However, this does not usually happen with ripe fruit, like apples, berries, melons and a few others that wild canids have historically had access to. The fact that dogs lack grinding molars and salivary amylase is often used as a central piece of evidence to support the idea that dogs are carnivores. What is never pointed out, however, is that neither of these is necessary in order to digest foods mostly composed of water and simple sugars, such as fruit. Although most dogs do chew them, these foods can be digested even without chewing.

We have enough information to know how to best feed our dogs

Clearly we would do well to leave our biases at the door when attempting to get to the bottom of an issue like this. Even if we do, the widely varying habits of wild dogs compounded by decreasing opportunities to observe them in pristine habitat make the job difficult enough. For the purposes of determining what to feed our dogs, however, we have ample information to allow them to enjoy much higher levels of health than they typically experience.


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{ 3 comments… read them below or add one }

admin July 7, 2011 at 2:08 pm

Yes, they are both, as I state in my article. However, field research is consistently showing that wolves do not eat the contents of the rumen/stomach. They do eat plant matter as a secondary food source, particularly when prey foods are scarce.


Mark October 9, 2011 at 8:29 pm

Most prey model feeders I know of are not adverse to feeding vegetables. The main difference is the vegetable matter is not counted as part of the meal plan. It’s generally counted as “table scraps”.

I think what’s important, no matter what “camp” you are in is that you realize that there can be a difference of opinion. I recommend, when people are looking at “raw” to study both and decide what they are comfortable with. I know people who feed BARF and will recommend a new person to raw gets in contact with them if that is their choice and it goes vice-versa. At the end of the day, “internal raw” arguments can only detract from the fact that raw in general is far better than a lot of commercial food available.

What I do not like about BARF isn’t the idea of vegetables, it’s the way it is being commercialized very quickly. I can imagine it running into the same problems as some commercial kibble where money is the be all and end all, not the quality of what is in the food.


James C July 3, 2012 at 3:47 pm

Hi there – love this article you wrote. It gives an objective perspective to both prey-model and BARF. I’m currently on prey-model with my puppy, but I like how you state that their diet might have to change when they reach middle-age.

Thanks again!


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