The internet is a place with a lot of conflicting opinions on this one, especially since those dogs are owned by people who want to either justify that they can feed their dog a vegan diet or that they can be in the right when they yell at those dog owners as impoverishing pets in the name of their own ethical dietary decisions.
They are physiological and biological carnivores-they can survive and thrive on a completely plant-free diet. However, unlike some carnivores, they have some adaptations that allow them to obtain calories from a wider range of foods. I would classify them as carnivores with an omnivorous tendency.
“Carnivore” and “omnivore” are biological terms that are essentially irrelevant in terms of the debates you mention in the OP. These are moral rather than scientific questions.
Dogs are members of the order Carnivora, but then again are pandas, whose diet is almost entirely leaves, and kinkajous, who eat mainly fruit. So in that sense they are “carnivores,” but that doesn’t say anything specific about the diet of individual species.
Cats are almost purely carnivorous. They eat virtually no plant material. Bears and raccoons are omnivores. They will eat just about anything they can get.
Wolves are mostly carnivorous, but even they will eat fruits like berries, apples, or melons.
Like wolves, dogs are mainly carnivorous but due to domestication they are even more prone to and capable of eating plant foods. It has been found that dogs acquired genes that made them better able to digest carbohydrates early in the domestication process, certainly due to the availability of such foods from humans.
As far as I know dogs should be able to survive on a vegetarian diet if care is taken to provide all necessary vitamins and nutrients. While this is not a “natural” diet for dogs, nothing about dogs is natural.
[QUOTE=spamforbrains]
They are physiological and biological carnivores-they can survive and thrive on a completely plant-free diet.
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I’m an engineer and not an expert on biology, but I tend to agree with spamforbrains.
If you look at this from a biological viewpoint, carnivores are specialized to eat meat. They have sharp teeth to cut meat. They have short digestive tracts that are good for processing meat but are too short to get many nutrients out of plant matter. Herbivores, on the other hand, have flat teeth to chew plants with, long digestive tracts to extract nutrients from plants, and often have something that allows them to process cellulose. Omnivores like us humans are a mix of the two. We have sharp teeth in the front, flat teeth in the back, and medium length digestive tracts that process a lot of nutrients from plants, but cellulose mostly goes in one end and out the other.
A dog’s digestive tract is a bit omnivorous. They can extract a fair amount of nutrients from plants, though like us, they lack any mechanism to digest cellulose. On the other hand, they don’t have any flat teeth at all. And yes, you can feed a dog a vegetarian diet, but you have to be careful about it. True omnivores like us don’t have to be quite as careful, though even we need to be a bit careful about what we eat if we try to go vegan (or even mostly vegan). No matter what some folks (like some extreme vegans) say, humans are not herbivores.
While a dog’s digestive tract kinda pushes it towards omnivore territory, dogs lack the proper teeth to chew on plant matter. So I would classify them as a carnivore with some omnivore-ish tendencies. They are more omnivorous than cats, who will die if you try to put them on a vegan diet. But they aren’t true omnivores like us humans. They just aren’t quite good enough at processing plant matter for that.
ETA: Colibri’s post wasn’t there when I started typing.
Dogs are facultative carnivores and do not depend solely on animal matter. A cat is an example of a obligate carnivore which is fully dependent on eating animal matter.
Omnivore does not have a tight definition but dogs and wolves prefer and and are evolutionarily geared towards meat. Contrast this with pigs which are typically considered omnivores and which mostly forage in the wild.
Humans like things to be in nice, neat categories, but nature doesn’t work that way. There are not just three distinct categories of carnivore, herbivore, and omnivore, but a whole spectrum (in fact, a multi-dimensional spectrum), and animals can be anywhere on that spectrum (or at least, anywhere that allows them to eat something).
What do veterinary professionals (hopefully those not paid by any part of the pet food industry) say? Is there a consensus among canine nutrition/health professionals?
Apparently cats can be considered on the upper end of the carnivore scale, unable to survive eating plants alone. I have vegan friends who researched this and realized they had to feed meat to their cat, certain enzymes just weren’t available from plants. Dogs can survive on a vegetarian diet, although I doubt any dog is happy to do so. Cats will eat vegetables though. In my experience they like carrots but not peas.
Cats eat grass, but that’s not for nutrition, that’s to help them deal with hairballs. In their case “chews and swallows this” doesn’t necessarially mean it’s food for them.
Yeah, two of my cats eat fibrous plant matter, and the other likes to eat ribbons, but none of them show any interest in eating any plant-based foods. One loves milk and lamb. Another will go to some trouble to try to steal chicken. Two will stick their faces into a fruit pie, and maybe lick the pastry (probably for the butter) but none will actually take a bite of pastry, fruit, vegetables, cereal, or any other plant-based food we might leave around.