Mystery of why cats eat grass (even when it makes them sick) could be solved

Beautiful cream tabby cat eating fresh grass on green background.
Why DO cats eat grass? (Getty)

Our feline friends are full of mysteries, but few are more mysterious than the question of why cats eat grass - and then are promptly sick on your carpet.

The reason comes from the distant past, researchers believe - and is an instinctive behaviour passed on from ancient cast ancestors.

Researchers from the University of California's School of Veterinary Medicine believe that cat ancestors would chew on roughage like grass to get rid of intestinal parasites.

Cats would pick up parasites from eating rodents, then eat grass to provoke muscle activity in their digestive tracts, flushing out the worms.

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Today, of course, it’s completely unnecessary, which may just add to the irritation cat owners feel when finding yet another little pile of sick inside their house.

The researchers write, ‘'Given that virtually all wild carnivores carry an intestinal parasite load, instinctive plant-eating would have an adaptive role in maintaining a tolerable intestinal parasite load, whether or not the animal senses the parasites.’

The researchers conducted an online survey of 1,021 cat ownrs and found that 71% of cat owners said their pets ate grass - including 39% of kittens.

The finding suggests that the habit is innate, rather than being learned from other animals.

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