Q: I’ve been researching diets for my dog, and some are high in animal protein while others seem to rely on grains and vegetables for protein. Aren’t dogs carnivores?
A: In veterinary school we learned that cats are carnivores (meat eaters), horses, rabbits and ruminants are herbivores (plant eaters), and pigs and dogs –– like people –– are omnivores (everything eaters).
But veterinary nutritionists have begun to rethink the “dogma” of dogs as omnivores. Here’s why:
• Dogs are more like wolves physiologically than we previously thought.
And wolves are clearly carnivorous. The current literature demonstrates that foraging comprises a tiny percentage of a wolf’s food intake, and that wolves tend to leave any grain-containing stomach contents behind after a kill. Dogs’ taste preferences seem to go in this direction as well: Meats first, grains later.
• Dogs have the intestines of a carnivore.
We used to think that dogs’ longer intestines meant they’d be better suited to eating grains. Truth is, the total volume of a dog’s intestines is pretty close to that of a cat’s. And cats are the ultimate carnivores.
• Dogs have more carnivorous traits than omnivorous traits.
In the 15,000 years dogs have lived beside humans, they’ve evolved. We’ve identified a few genes that reflect this adaptation, including three related to starch and glucose digestion. So it’s hard to deny that dogs have adapted to eating grains and other vegetation. Nonetheless, dogs still have plenty of traits that are 100 percent carnivorous:
— Their teeth are adapted to a carnivorous diet.
— Many of their innate behaviors are carnivorous in nature (digging, pack hunting, hiding food).
— Like many large mammalian carnivores, they’re metabolically able to survive for long periods between meals.
The bottom line, many nutritionists argue, is that the dog is a true carnivore that happens to have an adaptive metabolism as a result of its long association with humans.
That’s why a dog can eat the type of grain-based diets you mention. But is it best? Veterinary science has yet to conclusively determine that. Until we do, it’s up to you to decide what works best for your dog.
Dr. Patty Khuly has a veterinary practice in South Miami. Her website is drpattykhuly.com. Send questions to firstname.lastname@example.org.