When did dogs become omnivores and can they eat an omnivorous diet?

ORIGIN OF THE DOMESTIC DOG 

There is ongoing debate regarding the exact date of domestication of the dog, Canis familiaris. But what is known is that dogs have a long history of co-existence with humans. Humans originally lived as nomadic hunter-gatherers; this likely attracted carnivorous grey wolves (the dog’s direct ancestor) to scavenge. 

Between 13000 and 17000 years ago, when humans started to build settlements and agricultural techniques emerged, a new food source became available derived from cereals and other human food waste. Wolves opportunistically took advantage of this source, gradually becoming accustomed to human contact. Over generations, with multiple phases of domestication and then years of selective breeding by humans; they became the dog we now have in our homes.

DIGESTIVE SYSTEM

Dogs have several digestive and metabolic characteristics that differ from the cat, an obligate carnivore. The dog’s digestive system is similar to classic omnivorous species such as humans and pigs; whose diet includes high levels of plant-based ingredients. Dogs do not have a dietary requirement for the amino acid Taurine unlike cats, and dogs can digest carbohydrates from plant materials. A genome study of dogs and wolves, published in Nature Journal, 2013 found that dogs have genes enabling them to digest cooked starch. The study investigated genomes of 14 different breeds of dogs and compared them to genomes of wolves. The results indicated that dogs do can digest starch, breaking them down into sugars, an available energy source. 

DOGS ARE NOT WOLVES

Wolves, on the other hand, are true carnivores consuming a small amount of vegetable material. Additionally, unlike most dogs, wolves can experience extremes of feast and famine. Post-hunting wolves gorge on their prey, therefore, they need to cope with a highly variable nutrient intake requiring an adaptable metabolism, this ability is still present in our modern-day dogs. 

CARBOHYDRATES

Dogs’ have long utilised plant carbohydrates in their diet. From the early days of the commercial dog food industry plant-based ingredients have been included. Today a lot of commercial dog food contains high levels of carbohydrates. The image of the wolf that must eat high quantities of meat and avoid grains has only become common in the last decade, driven by the raw and ancestral feeding trend. 

STUDIES

Recent digestibility studies have conclusively proven dogs’ adaptions to digest starches. A 2008 randomized study examined six starch sources common in dog food (cassava flour, brewer’s rice, corn, sorghum, peas, and lentils) and found each to be over 98% digestible. (Carciofi et al, 2008)

In conclusion today’s domestic dogs have gone through evolutionary development and selective breeding via human intervention. Therefore, they can eat, digest, and derive nutrition from a wide range of ingredients, including plant based.

REFERENCES

Effects of six carbohydrate sources on dog diet digestibility and post-prandial glucose and insulin response A C Carciofi 1, F S Takakura, L D de-Oliveira, E Teshima, J T Jeremias, M A Brunetto, F Prada

Callaway, E. Dog’s dinner was key to domestication, Nature (2013)

Starchy Diets May Have Given Ancient Dogs a Paw Up, Stephanie Pappas  published January 23, 2013 Live Science

Dog domestication and the dual dispersal of people and dogs into the Americas, Angela R. Perri, Tatiana R. Feuerborn, Laurent A. F. Frantz, and Kelsey E. Witt