Whenever my cat sees a cup, he has to go inspect it and knock it over even if there is no liquid in it. He really likes drinking the water out of these cups too if there is any in it. I cannot ever leave any cup unattended around him without it being knocked over and the liquid spilt everywhere.
Is there any reason he always does this and are there any suggestions on how to stop it? He gets quite a bit of attention so I know that is not the reason.
There are several possible reasons that your cat could be exhibiting this behavior. What you do about it depends on why he is doing it.
Your water is fresh and clean. Perhaps his water is old or his bowl is dirty. You could try cleaning his bowl, refreshing his water more often, or installing a fountain to keep his water fresh.
Your water is near you (where he wants to be) while his water is far away. You could try making sure he has water near each place you hang out (in the living room for when you're watching TV, in the office for when you're on the computer, in the bedroom for when you're sleeping, etc).
He's bored. You say he gets plenty of attention, but petting and affection isn't the same thing as hunting with an interactive toy. You should make sure that he gets plenty of stimulating play toy with a feather wand or fishing lure type toy each day. At the end of the play session, feed him his dinner or a small treat to stimulate the natural hunt-eat-groom-sleep cycle.
Finally, sometimes cats just do things for reasons that we humans can't quite figure out. Often I'll remove the item that triggers the behavior for a few months (so stop leaving cups unattended) and by the time I start relaxing and allowing that item to remain in their environment, they'll have forgotten about that annoying behavior.
If you're providing you cat with plenty of clean water to drink I suspect this cat is just playing with the water. One of my cats tended to play a lot more with water when she was young. Typically this would involve dunking toys or other small objects in the water bowl. Attention and play are separate, one can give one's cat lots of love and attention and the cat might still want an outlet for its play behavior. Zaralynda's suggestion on stimulating play time might reduce his interest in these cups of liquid. At the same time he might be extremely fascinated by them and still want to interact with them even with extra play time. The final solution would be simply making sure those cups are not within his reach. Good luck.
I don't have enough rep to comment or this would be a comment instead of an answer, but I just wanted to add that if you're using glass cups, you may want to switch to plastic cups until you break your cat of this behavior. You wouldn't want him knocking a glass cup over and causing it to break, and have him or someone else get cut by the glass shards.
If you are using glass, then perhaps it's the reflectiveness of the glass that he is attracted to, also. :)
This is a popular topic in my household. One cat likes to dip her paws in glasses of water creating what we refer to as "cat paw flavored water". One cat likes to fish the olives out of martinis. One cat likes to flop down on its side on top of tables and knock anything over in the vicinity, especially a beverage.
In general you can discourage your cats from getting on tables and the like by nicely shooing them away or gently picking them up and putting them on the floor. They will often immediately jump back up - you have to be persistent and consistent. The second you give in they learn that if they are persistent they will get their way.
I don't recommend yelling at your cats or using things like water or squirt bottles to train cats. One popular cat behavior author stated it is bad for their self esteem.
Really without hiring multiple animal trainers and having them on site 24/7 for a week or two to re-train your cat you are not going to be 100% successful in changing your cats behavior here.
Sadly you are going to have to change your behavior:
Keep drinks out of their reach or out of their sight.
Drink out of spill-proof sports bottles, or plastic glasses with screw on lids and heavy straws. Anything like an infant's sippy cup.
Guard your beverages. If the cat is within 6 feet of your drink assume they will attack it shortly. Be ready to move to intercept the cat or secure the drink in your hand. Do not leave beverages unattended.
I employ all three strategies.
It is hard to say why they do it with utter certainty. I assume they just like to play with the water. Sometimes they might want a drink and it is easier to get a drink if it is overturned on the counter. Ensuring they always have fresh water may help. Some cats are fascinated by clinking ice. They may also just like to explore the cup or glass satisfying their famous curiosity.
Consistant and immediate correction is the only way you're going to change behavior, especially if the cat has figured out that doing this gets your attention and is doing it for that reason.
The simplest answer is going to be to declare that certain surfaces are Not For Cat. My cats aren't allowed on "food surfaces", those being kitchen counters and the dining room table. If I put objects I don't want them to tamper with on a surface that is officially "theirs" (including the living room coffee table), I accept that I may have to guard them. You will have to tell the cat "no" every time they go on the forbidden surface, and you will have to accept that -- being cats -- even after they understand the rule they may test periodically to find out whether it still applies. But if you actively enforce, you can carve out an agreement.
You also have to be very careful not to reinforce the undesired behavior. Saying "no" and then immediately picking the cat up to cuddle because you feel bad about doing so doesn't work. You don't need to punish (which doesn't actually work well), but you do need to avoid rewarding for long enough to make the point.
And even with all that, you may occasionally find the fuzzy ones make trouble for reasons that make sense only to them. They're cats. They can be persuaded to cooperate, but they need to understand why it's to their advantage to do so... and like kids, even when they know the rules they may try to cheat or push the boundaries. Be consistent, be firm, and if you can't explain a specific item to them try setting a more general rule which has the same desired effect.
