Have you ever seen your cat chewing on a patch of grass and thought “What on earth are you doing?” Cats are obligate carnivores. Around 2% of them are able to survive on a vegetarian diet and this takes some adjustment, even for those small numbers who can do it. However, it is pretty common to see cats munching on a patch of grass and not just domestic cats. Feral cats and even big cats do it frequently enough that we don't think it’s unusual. So in that case, why do cats eat grass?
Kittens Eat Everything
Just like babies, kittens explore the world by putting things in their mouths. This includes anything small on the floor, litter particles and grass. They’ll chew on it to play and because it moves so it looks like prey. Luckily, grass is completely harmless for them.
Just Cleaning the System
Mostly cats eat grass to help with their digestion. They don’t have the enzymes required to break down grass and vegetation since their digestive systems are designed for meat and protein. Quite often they will throw up shortly after eating grass. This is not something to worry about, however. The chances are that your cat has done this on purpose. By inducing vomiting, your cat is clearing out its system of other things that it also can’t digest, such as feathers, fur and bones.
When a cat catches a mouse, it can’t remove the meat from the fur and bones so it just eats the whole thing. It then eats some grass, which it throws back up, conveniently wrapped around the mouse bones. This way they don’t end up in the intestines where there’s a risk that the sharp bones could puncture the gut wall. While it may not be pleasant for either you or your cat, it is the best solution. These things clog up and irritate the digestive tract, so removing them will make your cat feel much better.
Cleaning Out The Other End
Grass also has a laxative effect for your cat and helps with regular, healthy bowel movements. Think of it comparatively to the insoluble fibre that we also need from our food. We don’t digest this, but it moves through the intestine and pulls out the things stuck in there. This is what the grass is doing for your cat’s intestines. It’s even more important for cats as their gut may get blocked by clumps of fur or other strange things that they’ve eaten so it needs regular cleaning.
Getting Some Extra Minerals
Grass contains a vitamin called folic acid. Cats use this to regulate the oxygen levels in their blood, as it helps to make haemoglobin. It's also present in cat's milk and supports growth in the kittens. If your cat is deficient in this vitamin, it may look to supplement it by chewing on some grass. It gets folic acid from the juices in the grass, so the fact that it doesn’t digest the carbohydrates is not an issue.
It seems that eating grass is a pretty normal thing for your cat to do and nothing to be concerned about. Cat’s are pretty savvy and will know when they need a little help digesting. If you find your cat eating grass quite frequently, have a look at the food you’re using to see if there is maybe a folic acid deficiency going on. If your cat is eating a lot of grass, this could also be a sign of intestinal issues and you may want to have a vet check it out.
Generally, eating grass causes no harm to your cat and may even provide it with some benefits so you shouldn’t try to prevent it. In fact, you should provide access to grass for your cats. If you have an indoor kitty that doesn’t have access to a garden, you can even buy pots of grass for your cat. Even though they may not have mouse bones to bring back out, your indoor cat will still have swallowed a good amount of indigestible fur while grooming. However, you should also avoid letting your cat chew on your houseplants. While grass is pretty harmless, some houseplants are toxic for cats. Otherwise, just leave them to it!