Cats are obligate carnivores, right? Yet any and every cat-owner can recall their tiny tiger happily munching away on plain old garden-variety grass. Heck, you can even buy “cat grass” - usually wheat grass in the form of seeds or lush potted plantings – as a treat to help your porch panther digest a meaty meal... or so we thought.

Now We Know Why Cats Eat Grass

Cats' grass-munching behavior has always been observed though it's never really been quantified until now. Kudos to researchers from the University of California, Davis surveyed over 1,000 cat owners on their pets' predilection for greens. Over 90% stated their cats were acting normally before chewing the turf and of those who did, roughly a quarter of them vomited afterwards. So, what were the other 75% thinking?

They weren't thinking at all, according to the researchers' presentation at the International Society for Applied Ethology's annual meeting in Bergen, Norway. In a nutshell, cats eating grass is an evolved instinctual behavior.

Now We Know Why Cats Eat Grass

Back in the days before domestication (and store-bought cat food), felines fed upon rodents that were often riddled with worms and other parasites. It was these parasites that tended to upset the predators' stomachs, and eating a little grass was an effective way to speed up their digestive mechanisms – or reverse them.

So don't take it personally if and when your cat gnaws on the shrubbery after feeding – it's not a passive-aggressive critique, just a time-worn habit. As for WHAT plants they nom on, purchasing cat grass online is a great way to keep pesticides and other lawn-treatment chemicals out of their systems. (via ScienceMag, images via Kaitlin and John Benson)

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