You've probably heard it said that humans are the only animals that can laugh. I say humans are the only animals that won't drink out of a toilet -- unless they're pledging for a frat.

I used to be pretty sure that humans were also the only animals that eat kale, until I saw an advertisement for kale treats for dogs. The ad brags that they are "grain- and wheat-free." If only they were kale-free, too, they might make a nice treat for a human with an eating disorder, but it sure doesn't sound like something a dog should be eating.

I think most dog owners are wonderful people who treat their animals as part of the family, who include them on vacations and picnics and sometimes let them eat table scraps. They take them to the vet, they make sure they have their shots. But in every group, you'll find some sick, twisted animal-hater who will feed some poor, helpless animal kale.

In case you've missed it, kale is supposed to be some kind of superfood that will cure everything from cancer to warts to tennis elbow to restless leg syndrome -- in humans. Which explains why it tastes so bad: It's medicine. Medicine is supposed to taste bad. How else will we know it's good for us?

Kale will even help you lose weight. You can eat as much of it as you want, and the pounds will melt away. Because you won't want any. The national dish of Iceland is rotten shark meat, which will also help you lose weight, because there's no way anyone not from Iceland can keep it down. One bite and believe me, you won't eat anything again for days.

Rotten shark meat could only taste worse if it was wrapped in kale, but even Icelanders have a limit to what they'll put in their mouths. So do sharks. Guess what sharks don't eat? That's right: kale.

Apples and oranges are good, healthy foods for humans, and so are raisins and blueberries. That doesn't mean you should be feeding your dog a fruit salad. Or a green salad with ranch dressing. Or mac and cheese.

Human food and dog food are, well, apples and oranges. Should I really have to say that in a newspaper? Just because it's good for you doesn't mean it's good for your dog. Isn't that simple common sense?

I've seen commercials on TV recently for gummy vitamins and gummy fiber supplements. And this wasn't advertising for children; it was on the nightly news, and we know how many young people watch that. None. It's funny, there were no ads for broccoli and peas, saying how healthy they are, but there are plenty of ads for gummy vitamins and gummy fiber chews. I wonder which is better for you? If there was only some instinct that would let us know which was better for us: real food or a gummy vitamin?

Now, I'm not a veterinarian -- I just pay for their college loans and their yachts -- but are any of them recommending that dogs eat kale? Aren't most of them recommending that dogs eat roughly what they would eat if there weren't any humans around to feed them grain-free kale kibbles?

Of course, that brings up another problem. No one would buy a can of dog food called "Three-Day-Old Roadkill" or "The Neighbor Kid's Pet Rabbit" or "Stuff From a Smelly Garbage Can Down the Block," but those would suit the dog just fine. So they have to come up with fancy, appealing names for stuff that's been left on the slaughterhouse floor like "Grilled Free-Range Chicken" and "Hearty Organic Beef Stew." And to the dog, it might as well be those things.

But if you really think your dog should eat kale, go ahead and put some raw, unprepared kale in his dish. See how much he eats.