File - Dogs are carnivores

The domestic dog and the wolf are one and the same. Dogs are not
omnivores, as some have claimed. Dogs are carnivores, exactly like
wild wolves. Geneticist Dr. Robert K. Wayne at UCLA has conclusively
proven that the domestic dog is a subspecies of the wolf. Subsequent studies
have verified this conclusion.

Next, it must be understood what wolves actually eat in the wild,
especially when they are not pressed by loss of habitat and human
intervention. Contrary to some claims, wolves do not eat the stomach
contents of their prey nor do wolves consume much vegetable matter.
The preferred food of the wild wolf is the meat, bones, and organs of large
hooved Mammals. In times of scarcity, desperate wolves will try to eat a variety of
food items, just as would any starving creature, but they strongly prefer to eat
meat, organ, and bone. Dr. L. David Mech has been studying
wolves for decades, and has published many books and articles on
wolves and their diets.

Dr. Wayne's website:
http://www.eeb.ucla.edu/indivfaculty.php?FacultyKey=501

Dr. Mech's website:
http://www.davemech.org/biography.html