Wild hunting cats and dogs consume some greenery when they eat the stomach contents of their prey, and non-hunting pets may need to get this vegetable matter by other means. Even big cats such as cougars eat grass.
Grass eating is a natural behaviour for cats and dogs, and biologists and veterinarians have offered several theories to explain why pets need a little greenery.
It’s not known for sure why cats and dogs eat grass and other plants, but the most plausible theories are that grass is needed as:
- Roughage (for its laxative effects)
- An emetic (to help with vomiting up indigestible matter)
- A vitamin supplement
It’s possible that all three of these requirements contribute to grass eating.
When cats and dogs consume prey whole in the wild, they often consume bones, fur, feathers, and other indigestible parts. Cats also swallow their own fur during grooming, and if hairballs form, they must be either vomited up or moved down through the digestive tract efficiently so that they don’t cause a digestive obstruction. Grass may help with inducing vomiting and providing laxative fiber that moves hairballs and other indigestible matter through the digestive system, preventing obstruction and constipation.
Some biologists have suggested that cats and dogs eat grass to obtain small amounts of critical nutrients, particularly folic acid. Folic acid is a vitamin that aids in hemoglobin production and other functions. If they don’t get sufficient folic acid from their diets, animals can become anemic, so they may eat grass to obtain trace amounts of this vitamin, and perhaps other nutrients as well.
Grass Eating is a Natural Behaviour in Cats and Dogs
Most cats and dogs will snack on grass if given the opportunity, and grass-eating is only a problem if the grass is coated in toxic pesticides (those with gardens should use non-toxic pest control to avoid poisoning free-roaming pets). Dogs can usually get their fill of grass while out on walks, but an indoor cat doesn’t have this opportunity, so a pot of cat grass should be provided.
If your pet is targeting houseplants, see How to Stop Cats Eating Plants for solutions and avoid keeping highly toxic plants such as lilies and sago palms where pets can access them.
For more cat articles, see the main Cats page. For more dog articles, see the main Dogs page.
References:
- Bush, B. (1984). The Cat Care Question and Answer Book. Boston, NY: Bookthrift Co.
- Busch, R. (2004). The Cougar Almanac. The Lyons Press.
- PetMD.com. (2010). “Why Do Cats Eat Grass?”
- Nelsen, K., Dr. (4/2/2010). “Sago Palms are Poisonous to Animals.” Dr. Nelson’s Veterinary Blog.
- Tobiassen Crosby, J., DVM. (n.d.). ” Frequently Asked Question: Why Does My Dog (or Cat) Eat Grass?” About.com.