When it comes to dog food, the choices seem endless. Photo: Wikipedia.

Dry dog food or kibble. Canned dog food. The raw or BARF diet for dogs. Homemade dog food. Holistic and organic, frozen specialty and raw dog foods. Vegetarian dog food. Table scraps or not, "human" food or not. The choices are almost endless these days, and many dog lovers have a lot of questions.

Is a dog a carnivore or an omnivore?

Dogs are classified scientifically as carnivores just as cats are. However, the scientific classification isn't based on diet so much as physical characteristics. For example, bears are classified as carnivores but most are omnivorous in their habits except for the polar bear and the giant panda: the polar bear consumes flesh almost exclusively whereas the giant panda feeds primarily on bamboo.

Cats, on the other hand, are obligate carnivores which means they cannot survive without a diet consisting primarily of meat. Dogs are considered by many to be "opportunistic scavengers" despite their scientific classification. That means that although dogs thrive on a meat-based diet (and most dogs will choose a steak over green beans any day) they may survive on an omnivorous diet and whatever they find even if it's not meat. Cats can't do that.

How well and how long the dog would survive is the question and what dog owners are concerned with when thinking about diet.

Despite controversy, most experts agree that dogs do best on a high quality, meat-based diet with—depending on which expert you're talking to—varying amounts of carbohydrates that come from vegetable matter such as grains.

Part 2: What is the best choice for my dog?

Pets 101: Where can I buy organic and natural pet food?