I have been told that dogs can be vegetarians...but cats cannot. Pesonally, I give my dog chopped up vegtables (lightly cooked)and some grain and he has no problem eating them, but mixed with organically raised meat. However, I have been told by several nutritionts...both canine and human, that dogs can live without meat and do quite well. I know that some dogs enjoy muching on a raw carrot as a treat, and I have heard of dogs who steal avacados from their neighbor's yards on a regular basis.
In my opinion, judging from their teeth and digestive systems, they should have some meat, so even tho I have been told this, I have not tried it, but feeding them a veggie diet would be better then feeding them commerical pet food....
Everyone keeps saying that "in the wild.... etc. etc. BUT they are NOT in the wild. In the wild, they might eat meat one day and then go without eating it again for several days. In the wild, they also have to deal with extremes in temperature, weather...and they get unlimited amounts of exercise - hunting is hard work. On the othe hand, in the wild, they do eat more vegetable matter than you might imagine...coyotes have been known to eat up to 25 differnt kinds of herbs...for medicinal reasons, as well as grasses, berries or any fruit lying around.
Also, dogs have not been wild for centuries...and toy poodles and the like have evolved a long way from their wolfy brethern. So feeding all dogs as if they were wild does not always make sense. You have to make allowances for the breed and the lifestyle.