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Why do dogs eat grass? A look at your pup’s wild relatives may give you a sense of what dogs’ diets are really like.

Hosted by: Hank Green
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It's a tale as old as time, or at least, as old as dogs. You let Fido out the door, and immediately he's munching on the grass like it's covered in bacon grease. Maybe that dog threw it up later, more likely it didn't, either way, it begs the question: why do dogs eat grass?

One commonly held theory is dogs use grass as the natural remedy to induce their own vomiting. The idea here is that Fido might start grazing when he's feeling gassy or there's something else going on in his digestive system that he wants to get rid of. But so far, there's actually not too much evidence for that, although eating grass can lead to vomiting, that typically only happens to about 25% of dogs. Instead, the simplest explanation is that dogs eat grass because they like it. Let's face it, the average dog will attempt to eat pretty much anything given the chance, and keep in mind that wolves and coyotes and other wild canines regularly dabble in plant eating. 

Unlike cats who are purely carnivorous, dogs are omnivores. So not only will they scavenge anything if they're hungry enough, including fruits and berries and grass, but many wild dogs also hunt herbivores and devour their stomach contents whole. 

So some experts believe that grass eating may be a natural way for domesticated dogs to have a varied diet. Now, if your dog is eating a lot of grass, he or she might have some kind of nutritional deficiency.

Dogs, like us, don't have the enzymes to break down cellulose, the main energy source in grass. So they may just be grazing for a source of fiber. But some grasses can provide decent amounts of minerals, like phosphorous and calcium and potassium, which might explain why some dogs are known to only eat certain kinds of grass.

Either way, a little grass-eating can be normal and harmless, assuming the grass wasn't just hosed down with a bunch of herbicides and pesticides.

But if you're worried about your dog's nutrition or digestion, you can always ask your vet for advice on changes to your pup's diet. You can also be thankful that they're going for the grass instead of the poop, because that's a thing that happens! But that's for another episode!

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