A recent study found that when humans transferred from being hunter-gatherers to farming their pet dogs’ diet changed from meat to plant-based foods. When grey wolves first became domesticated and became domestic dogs they would have been eating meat almost exclusively but with the advent of agriculture there was a huge shift in their diet.
As human hunting decreased their diet was based far more on vegetables resulting in dogs also beginning to feed on plants, mainly cereals, so said the lead author, a zoo archaeologist, Sylvia Albizuri, from the University of Barcelona. Her study is published in the Journal of World Prehistory.
They studied the remains of 36 dogs in Can Roqueta which is about 15 miles north of Barcelona. An area that was first inhabited by people in the Stone Age. The dogs had been buried clearly indicating that they were domesticated and used as working dogs.
The scientists were therefore able to analyse the bones of these dogs; studying the carbon and nitrogen levels which can tell them about their diet. They decided that ten of the dogs were omnivores while nice had a diet high in meat. Seventeen of the dogs showed almost no sign of having a meat diet. Tests on the cattle that they guarded had similar levels of carbon and nitrogen.
They also decided that over generations on this diet they would have evolved to having weaker jaws than their wolf ancestors. Further, their molars would have been smaller and flatter so they could better grind plants and grains.
In northern regions hunter-gatherer societies tended to persist and therefore their pet dogs would still have lived on meat. Moving forward, a UK study found that one in five dogs are fed a vegetarian or vegan diet by their owners. Incidentally, rarely, cat owners believe that they can feed their cat a vegan diet. They can’t because cats are obligate carnivores but you can buy commercially prepared plant-based cat food which contains added supplements and which in my opinion is balanced and satisfactory for cats.