Why Do Dogs Eat Grass?

 

It's not uncommon to see your dog grab a mouthful of grass during their daily walk or a romp through the park. Ever wonder why dogs do that?

There are many speculations as to why dogs eat grass. Many people believe that when dogs eat grass, they are trying to make themselves vomit. They think it’s an instinctive behavior that a dog engages in to rid themselves of something they should not have eaten.

Some pet parents think dogs eating grass is an indication that their pup has an upset stomach or intestinal problem.

Others believe that grass contains some essential nutrient their dogs instinctively know they need, or that grass offers much-needed fiber that aids in moving food through the dog’s gastrointestinal tract. They think that grass may serve as a laxative to help move stool along for dogs that are constipated.

But what’s the true science behind dogs eating grass?

Testing 6 Reasons Dogs Eat Grass

There have been many speculations and theories, but there is limited research on exactly why dogs eat grass. So the truth is … that no one knows for sure. However, scientists have formed a few theories and disproved some myths based on the research we do have.

1. Instinctive Behavior

Some scientists speculate that eating grass is an instinctive behavior for dogs that evolved from their wolf ancestors. We know from research on wolves that 2-10% of their stomach contents may contain plant material. Wild canids (from the Canidae family, which includes wolves, jackals, foxes, and coyotes) also have been observed to eat grass.

2. Supplementing a Missing Nutrient

In one particular case report, an 11-year-old Miniature Poodle had a 7-year history of eating plants and grass and vomiting afterward. The problem resolved after the dog was placed on a commercial high-fiber diet. This was evidence that this particular dog was supplementing his dietary deficiency by eating grass and plants. Once provided with adequate fiber in his diet, the grass-eating behavior resolved.

But can dogs actually digest grass? Dogs are primarily carnivores, meaning they eat meat. But recent studies have shown that dogs have evolved the ability to digest some carbohydrates in response to coevolving with humans. (Carbohydrates are sugar, starches, and fibers mainly found in fruit, grain, vegetables, and milk products).

If dogs can digest some carbohydrates, then does this mean our dogs can really digest grass? The answer is no, not really. Grass mainly passes through the dog’s intestinal tract undigested.

3. Normal Dog Behavior

In another study from 2007, researchers found that grass-eating behavior was influenced by how hungry your dog is and the time of day. There was less grass-eating when the dog had eaten a meal, and increased grass-eating beforehand. Grass-eating also occurred less frequently later in the day. The researchers believed that eating grass was normal dog behavior and was not indicative of an underlying illness.

4. Soothing an Upset Stomach

One study fed one group of dogs were a diet containing fructooligosaccharide (FOS). The other group of dogs were fed a standard diet. FOS is extracted from sugar beets and passes undigested through the small intestines and into the large intestine, where it ferments.

Large quantities of FOS can cause watery, loose stool. The dogs fed the standard diets had more episodes of grass eating compared to the FOS dogs that had diarrhea. This meant that dogs with gastrointestinal upset were actually less likely to eat grass.

However, in this particular study, the diarrhea originated in the large intestines, so it doesn’t give us insight on grass-eating behavior in dogs that have gastrointestinal upset in their stomach or small intestines.

5. Curiosity

Dogs, especially younger dogs, often explore with their mouths. Eating grass may be something that they try, like how some children eat dirt. Some dogs may learn to like the taste of grass.