A little over a year ago, the Humane Society of the United States (HSUS) (America's richest animal rights group) began experimenting with a new tactic that mainstream animal lovers and veterinarians had never seen before: trying to convert carnivorous dogs into meat-shunning herbivores. Suffice it to say, dog owners and veterinarians who understand canines' natural instincts still aren't flipping for HSUS's vegan kibble.

Promoted by HSUS CEO Wayne Pacelle as "a nutritious, environmentally friendly and ethically responsible food for our best friends," CNN today decided to see if meat-free dog food like HSUS's "Humane Choice" is the right choice for dogs' diets. Former HSUS Vice President Michael W. Fox said he's not sold on the concept that his former colleague is currently endorsing and marketing:

[W]e don't have the real science to back up whether it's safe enough, so, for dogs' sake, we need to adopt the cautionary principle.

HSUS promotes its vegan kibble as safe for "adult" dogs, citing a 2006 report from the National Research Council (NRC) to make its case. According to the NRC, "[D]ogs can survive on a vegetarian diet as long as it contains sufficient protein and is supplemented with vitamin D."

Few dog owners or veterinarians will disagree that dogs "can survive" as vegetarians. Placed under extreme circumstances, humans have resorted to atypical and unorthodox forms of nourishment in order to survive. However, we certainly don't resort to such radical means of satisfying our natural hunger instinct when our lives are not in peril—and we don't need to put dogs on meatless diets unless their own survival is at stake.

Pet expert and author Tracie Hotchner told CNN she understands why vegetarians might believe their dogs are capable of following suit, but questions whether that's "what's best":

Overall, it is much easier and more reliable to supply a dog's essential nutrients in a food containing both plants and meat …

I say respect each species for what it was meant to be, and if you feel that strongly about being vegan, get a vegetarian animal. Bunnies make wonderful pets.

After all, have you ever seen a dog pass up a steak?

Obviously, the choice is yours to make for your own dog. Will it be a "Humane Choice" based on a meat-shunning ideology that conflicts with your dog's natural instincts, or one that, as Hotchner reminds us, "respect[s] each species for what it was meant to be"?

We know that HSUS believes Wayne Pacelle can "speak for the animals," but maybe it's finally time to organize a "Humane Choice Challenge" to see if dogs actually prefer vegetarian cuisine. Something tells us it won't get the doggie slobber flowing like the smell of bacon.