The Simple Answer to “Why Do Dogs Eat Grass?”

You’re probably not going to believe me, which is fine.

Everyone has their own pet theory regarding the real reasons dogs eat grass, the reason that’s clearly, obviously right. These theories range from “Dogs eat grass to make themselves throw up,” to, “Dogs eat grass to make up for some unmet dietary need,” to, “Dogs eat grass to purge their systems.” Everyone has their favorite theory (as did I), and they hold onto them with the firmest of grips (as did I). So, finally scientists from UC Davis decided to look into the matter and here’s what they found:

These theories are all bohunk.

Leaving aside the somewhat thorny ethical question of why someone decided to look into this non-issue for a moment (really, dogs eating grass won out over malaria!? Won out over brain cancer!?), let’s take a gander at what they found.

  • Looking at about 1,500 dogs (which is huge by veterinary study standards – we’re usually lucky to get 40 or 50 dogs enrolled), they found that somewhere between 70 and 80 percent of dogs ate grass, usually weekly. I’d have to say this lines up with my experience as my dumb-happy and lovable three-legged dog, Rocco, can usually be seen out in the yard, noshing on some greenery about once a week. So, right here, you know something is up with the above theories – there’s just no way that 80 percent of all dogs have dietary unmet needs or “just need to throw up.” Dogs are not supermodels, and nature in general frowns on animals that waste food by throwing it up without good reason.
  • Less than ten percent of dogs were reported to be ill around the time of eating grass, and less than a quarter of them vomited afterwards. If they’re eating grass to make themselves vomit (presumably so they’ll fit into that little black Dolce & Gabbana number), then they’ve picked a pretty inefficient way to go about it. The vast majority of dogs who eat grass are feeling just fine, thanks very much, and don’t get all whoopsy afterwards.
  • If you’ve noticed your dog vomiting after eating grass, it’s natural to assume that one caused the other because these things are linked in a short timeframe. But that doesn’t mean one caused the other. Try this little experiment: Turn your TV to Golden Girls for one solid week, then note if your dog vomits. If they do, then clearly the Golden Girls are to blame. Poor Blanche.
  • They do postulate that the roughage in the grass may have helped ancestral dogs rid themselves of worms, but there’s no science behind this theory. They were just sorta riffing and tossing ideas about. So, while this does offer up some sort of explanation for the behavior, it remains to be tested. Guess brain cancer and malaria will have to wait just a little bit longer.

So, if you have a dog that eats grass (and odds are that you do, just like mine), when should you worry? Well, if you’ve just sprayed dangerous petrochemicals on the lawn to kill those evil dandelions (really, a dandelion’s biggest crime is being successful), best to not let your pooch out for a trip to the salad bar. Most pesticides are safe for dogs and kids to walk on when dry, but I’d be pretty nervous about letting my dog eat grass that was recently sprayed with anything, dry or not.

If your dog is losing weight, vomits or has diarrhea regularly, then it doesn’t matter how much grass they’re eating – they need a checkup with your vet. It could be anything from a routine stomach bug to something more serious like inflammatory bowel disease (IBD), a foreign object causing a blockage, pancreatitis or certain types of cancer.

So, after careful scientific evaluation and analysis, what’s the real reason that dogs eat grass? Well, the answer is the punch line to an old and off-color joke about male dogs, one that I really can’t in good conscience reproduce here:

Because they can.

Tags: , , , , , ,

  • Print
  • email