Why Do Dogs Eat Grass?

By Dr. Dave Summers

While there are many theories on why dogs eat grass, there has never been any proof as to why dogs practice this behavior. A study of 1,694 owners with dogs that had eaten plants in the past showed the following results.

  • 90% of the dogs ate plants during the period of the study
  • 79% of the dogs ate grass
  • 10% ate fruits or vegetables
  • 1% vomited after eating grass, suggesting that dogs do not eat grass to induce vomiting

Multi-dog households reported a higher incidence rate of dogs eating plants, which could mean that it’s a learned behavior that one dog teaches the others.

In addition, no correlation was found between plant eating and the type of food fed, including raw diets, suggesting dogs do not consume plants due to a deficiency in their diet. Plant eating was also found to have no correlation with sex, breed, illness, parasites, medication, eating of other foreign objects or behavioral problems.

In another study observing wild wolves, grass was often found in their scat. This was long stem grass, not the short pieces of grass found in the digestive systems of the animals they were consuming. This should help dispel another myth that wild Canids eat the grass from in the stomach of their prey. While the visceral organs are the prime dish at the banquet, the visceral contents are usually avoided if possible.

The research suggests that grass eating appears to be a natural behavior for dogs and wolves. We do not know why they eat grass or other plants, but it is unlikely due to the existing myths given for this behavior.

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