Mythbuster: Are dogs carnivores?


I’m sure you’ve heard it before – ‘dogs have descended from wolves’ or ‘dogs are carnivores by nature and do best on a diet of only meat’. For some time, there has been heated debate amongst scientists, vets and dog lovers more generally around whether dogs are carnivores or omnivores by nature. We take a closer look at both sides of the debate and the science behind it to determine what this all means for our dogs’ diet today.

First let’s look at what it means to be a herbivore, carnivore or omnivore. A herbivore feeds only on plant-based materials, for example cows and horses. In contrast, a carnivore feeds only on meat, for example it is generally agreed that most species of cats are carnivores. An omnivore easts food from both animal and plant origin, indiscriminately. For example, humans are considered omnivores.

Unfortunately in the case of dogs it’s not so straight forward so let’s take a look at some of the arguments.

The origin diet - are dogs really descendants of wolves?

Similar to the Paleo diet for humans, one of the arguments often used in favour of dogs eating a strictly meat-based diet is their origin and supposed evolution from carnivorous wolves.

Although once upon a time, scientists believed that dogs descended from the grey wolf, we now know from genetic studies that they share a common ancestor rather than a direct lineage. It is now believed that wolves and dogs split from their shared ancestor 25,000 to 35,000 years ago when humans were still nomadic hunter gatherers. There is now strong scientific evidence to suggest that dogs began to start eating and evolving to digest plant-based materials well before domestication. In fact, the evolution of their ability to digest starch and some carbohydrates may have actually been the catalyst for dogs and humans to coexist more closely and the start of the ancient bond.   

A lot can happen in 35,000 years and studies have concluded that domestic dogs today, unlike wolves, have not only evolved to eat plant-based materials but now possess 3 genes related to starch and glucose digestion allowing them to eat and digest grain-based carbohydrates.

Looking closely at the history of dogs, we now know that, unlike wolves, ancient dogs were most certainly able to eat and digest plant-based foods and possess specific genes relating to carbohydrate digestion.  

A look inside your dog’s tummy

After considering dogs’ dietary evolution we continue our hunt for answers in the most obvious place, their gastrointestinal system.

The length of an animal’s intestines provides an important clue as to the diet of the animal. Carnivores generally have much shorter intestines than herbivores as meat is easier to digest than plant-based material. On a relative basis, after adjusting for the size of the animal, a dog’s intestines are longer than that of a cat and other carnivorous animals but less than that of a human.   

As well as intestinal length, the coefficient of fermentation (a measure of the body’s ability to extract nutrients from plant-based foods) is also a key factor. In this measure, dogs again have a lower coefficient than humans however have a higher coefficient of fermentation relative to other animals that we know to be carnivores (such as cats).

From this we can conclude that whilst dogs are most certainly omnivorous like humans, they are closer to carnivores on various relevant measures than humans and as a result, their bodies are designed to eat more meat than humans.

What does this mean for my dog's diet?

Understanding the origin and gastrointestinal make-up of dogs shows us that, while dogs are omnivores by nature and will maintain optimum health on a balanced diet, their bodies are designed to be more carnivorous than that of humans, hence requiring a different balance of macronutrients to our own. It is important to understand that feeding your dog too much meat can be just as detrimental as not enough - protein metabolism generates a toxic waste product called ammonia which is processed in the liver & kidneys before being excreted. Over time a dog that eats a diet with too much protein can overtax these organs leading to degenerative diseases such a renal failure and cirrhosis.         

So how much protein is the right amount? Generally speaking, we believe a macronutrient split of 40/30/30 of protein/fat/carbohydrate (respectively) with a diet including at least 50% meat and including some organ meats is optimal for your dog’s health and wellbeing.  

Unfortunately in order to keep costs down and profits up many commercial pet foods use cheap low-quality ingredients that don’t align with the ideal macronutrient profile that dogs require and cooking for your dog at home can be tricky to balance nutritionally. Here at The Wholesome dog we tailor a meal plan to your dog’s unique profile and prepare fully balanced and nutritionally complete fresh, healthy dog food delivered to your door - discover your dog’s recommended meal plan today.

Image: @ps.ny

About the author

Andrew is a certified canine nutritionist with a passion for helping all dogs live longer, healthier and happier lives through proper nutrition, care and owner education. Currently a doting Dad to Daisy, a loveable Golden Retriever. Over the years he has loved and cared for Australian Terriers, Border Collies and a particularly sweet Maltese Shih-Tzu.