I believe we should go back to natural innate (wild cat) behavior to work out why cats knock things off shelves or tables. The video below is a nice example of this cat phenomenon.
Of all the answers on Yahoo Answers the most common is that a cat is seeking attention when they knock object off tables.
I don’t think this is the answer. I think it is anthropomorphising a cat, turning the cat into a child. I know cats sometimes behave like children and we often treat them like children but they are cats and their behavior is closely linked to wild cat behavior. They are domesticated African-Asian wildcats.
We can see cats push dead or dying prey around the ground. This is a form of rather cruel (by our standards) play it seems to us. But as our cats get relatively little (compared to wild cats) chance to hunt and express their natural instincts they like to maximise hunting and killing time when the opportunity presents itself. This is expressed in pushing the prey around. It is also a safe way of killing prey – battering it to death at arms length.
Pushing objects off tables is closely related to this behavior, I would suggest. I would say it is a part of their natural hunting instinct being expressed in domestic – human – environment. The particular attraction of knocking an object off a table is that for a second or two the inanimate object becomes animated, almost alive, as it flies through air falling to the ground. The cat watches this intently you might have noticed. They want it to become alive.
The cat pushes the object off the table to create prey. If I am correct we are, in general, not satisfying our cats enough in respect of allowing them to express hunting drives and skills.
Do you have an idea of your own?
P.S. I would like to thank Dorothy for showing me the video and getting me to think about this behavior.