Many of us spend our lives in loyal servitude to them, but cats remain a deeply mysterious creature. Do they actually hate humans? Why, as YouTube has shown us, are they scared of cucumbers? Why do they eat grass only to puke it back up a few minutes later?
This last question has been the subject of inquiry by researchers at the University of California‘s School of Veterinary Medicine. Presenting their findings at the 53rd Congress of the International Society for Applied Ethology in Norway this month, they questioned over 1,000 cat owners across the US about their feline companion and their plant-eating habits.
Here’s how the cat-puking data broke down: Over 60 percent of cats had been seen eating plants on at least 10 separate times, while just 11 percent had never been spotted doing so. Most of the time, the plant-eating did not affect the cats, although around 27 percent of cats tended to vomit shortly after. There was no notable difference between the grass-munchers and the non-grass-munchers, except for their age. Among young cats, 3 years of age or less, nearly 40 percent of them engaged in daily plant-eating compared to 27 percent of cats 4 years or older.
The most common explanation for grass eating is that the cat feels ill beforehand and plant-eating induces vomiting, making them feel better. However, the team of researchers suspect a different motive. Instead, they believe it's an “innate predisposition” shared by wild ancestors. Citing research carried out on primates, the researchers suggest that wild animals often eat non-digestible grass to purge the intestinal tract of parasites.
“Given that virtually all wild carnivores carry an intestinal parasite load, regular, instinctive plant-eating would have an adaptive role in maintaining a tolerable intestinal parasite load, whether or not the animal senses the parasites,” the team explain in a summary of their research.
The team didn't explore one common anecdote-based hypothesis: cats eat grass to help hock up hairballs that have gathered in their guts from incessant self-grooming. Nevertheless, while a gagging cat isn’t the most pleasant sight, the researchers argue that it’s actually a natural part of feline life and shouldn’t raise too much concern.