Why does my cat knock things over?
One of my favorite cat memes reads, “If the earth was flat, cats would have pushed everything off it by now.”
Another says, “Fact: Cats knock stuff off tables because they’re studying gravity. They’re not jerks. They’re scientists.”
Cats knocking things over is such a “thing” that even non-cat-owners know about this behavior. That’s why the memes are funny. Everyone gets the joke.
For those of us who have not watched a cat deliberately push a spoon covered in tomato sauce off the kitchen counter, or watched helplessly as a favored knickknack gets shoved from the mantle, cats like to nudge objects and watch them fall from a height. They may walk blithely across a messy desk casually knocking pens and paperclips to the floor as they go, or they might prefer to make a big splash with something big and breakable. After, they’ll dart off in triumph while their humans rush in to pick up the mess.
Is your cat honing her hunting skills?
There are plenty of credible theories about why cats knock things over. One, posed by Dr. H. Ellen Whiteley has merit. “’Toying’ with prey is a common behavior in feline hunters. When your cat nudges a small, stationary object with her paw, she's practicing the same behavior.” She adds, “Your cat's instincts tell her that paperweight or knickknack could turn out to be a mouse. Her poking paw would send it scurrying, giving her a good game (and possibly a good lunch).”
Is your cat getting a rise out of you?
Perhaps you’re well trained. Your cat shatters something precious on the tile floor and you come running, making a hullabaloo. Maybe next time they’re bored they’ll remember how to stir things up. Ask yourself if your cat has trained you to come running and put on a show when they “call.”
And how about if you’re sleeping late on weekend and breakfast has not yet been served? Kitty knows how to get your attention: by knocking your books and glasses off the nightstand, perhaps? Be aware if you’re being trained to respond to your cat’s demands.
Is it just for fun?
Cats like the ball that rolls, the spider that crawls, the leaf that blows in the wind. Cats like movement. Perhaps watching an item fall is its own reward.
A wild cat lives in a world in which everything moves. Indoor life might be a bit dull for our house cats so they make their own movement by knocking objects hither and thither.
Cats understand physics
In 2016 Japanese researchers published a study that concluded that cats seem to understand gravity. They devised a unique experiment in which balls rattled around in a box sometimes made noise and sometimes didn’t, and sometimes fell out of the box and sometimes didn’t. They allowed the participating cats to watch while researchers shook the box.
They used the “expectancy violation method” to interpret the cats’ behavior. Cats stared at the boxes longer when the conditions violated physical laws, as when the shaken box made no noise but balls dropped out anyway, or when the shaken box made a lot of noise, but no balls dropped out. The scientists’ conclusion, “This study may be viewed as evidence for cats’ having a rudimentary understanding of gravity.”
Tell that to your favorite Venetian glass vase as it sails to the floor: it was a sacrifice in the name of science, and that meme wasn’t a joke afterall.
 Whiteley, Dr. H. Ellen. "How to Solve Cat Behavior Problems." howstuffworks.com, animals.howstuffworks.com/pets/how-to-solve-cat-behavior-problems5.htm. Accessed 12 Sept. 2019.
 Takagi, Saho, Arahori, Minori, Chijiiwa, Hitomi, Tsuzuki, Mana, Hataji, Yuya, Fujita, Kazuo. "There's no ball without noise: cats' prediction of an object from noise." 14 June 2016. link.springer.com. link.springer.com/epdf/10.1007/s10071-016-1001-6