People often think of cats as weird—as if human behavior is so logical.

But it’s true we often need help decoding our feline pals. So we put out a call to our readers for their most puzzling cat questions, which range from dietary mysteries to those spontaneous “zoomies” around the house. (Related: Is everything you think about cats wrong?)

Why does my cat drink from the faucet?

Some cats find running water interesting, and prefer its taste to still water, according to Debra Zoran, an internal medicine specialist at Texas A&M Veterinary Medical Teaching Hospital.

Standing water can taste unappealing if the bowl isn’t kept clean and fresh, for instance.

Cats also have sensitive whiskers, which they’d prefer “not touch the sides of a bowl, or anything else, while they are eating or drinking,” Zoran says by email. This happens if the water bowl is deep and isn’t kept full. (Learn surprising things you never knew about your cat.)

View Images Cats may like the taste of running water better than what's in their bowls. Photograph by Cynthia Valdez, Alamy

It may also be that elevated areas, such as the kitchen sink, “make them feel safe,” Lena Provoost, an animal behaviorist at the University of Pennsylvania School of Veterinary Medicine, says by email. The water bowl they’re snubbing may be in a place with lots of annoying foot traffic.

Why do cats eat grass?

“Grass and plant-eating is considered a normal behavior in cats,” and may even help reduce parasite loads, Provoost says. It’s likely a trait that’s been passed down from wildcat ancestors, which ate vegetation to essentially scrape out the intestines, purging invaders like worms.

Grass is also a natural fiber “important to general gastrointestinal health,” Zoran says. In the wild, cat species might get some fiber from plant matter in the guts of prey animals.

Many owners provide their indoor cats with grass to eat. A sudden increase in grass-eating can mean an upset stomach from a hairball or other source, or, in multi-cat households, it could be a sign of anxiety.

Why do cats thump their leg on the door or other flat surface?

The cat in this video seems to have learned to get his human minion to open the door by knocking. Our reader’s cat, however, does this on other flat surfaces, such as walls and kitchen cabinets.

To Nicholas Dodman, professor emeritus at Tufts University's Cummings School of Veterinary Medicine, both show the characteristics of neutered male cats’ phantom spraying or marking. These males go through all the choreography of spraying, backing up to a surface, treading legs, and quivering tails, it’s just that no urine comes out. (See our favorite photos of pet felines.)

Cats mark with urine (or phantom urine) “often out of frustration or territorial concerns,” says Dodman, author of The Cat Who Cried For Help, and it’s usually in a prominent place that has “strategic significance” to the cat, including the edges of their territory or where their food is located.

There are also scent glands in the foot, though Dodman thinks that this isn’t a major part of the marking process.

Why do cats run around crazy when the weather changes?

Nicknamed “the zoomies,” these bursts of activity can happen at any time and are just a release of pent-up energy after all those nice, long cat naps.

Some cat owners notice the zoomies pick up when seasons shift. If they open up the windows for some fresh air, indoor cats, which are still hunters at heart, will be “stimulated by the presence of prey, new noises, new scents in the air, and will literally climb the walls, curtains,” and whatever else they can, Zoran notes.

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Enrichment structures such as cat trees can be a big help to giving kitty a chance to take it all in. (See vintage photos of pampered kitties.)

Why do some cats dislike belly rubs?

Hair follicles on the belly and tail area are hypersensitive to touch, so petting there can be overstimulating, Provoost says.

“Cats prefer to be pet and scratched on the head, specifically under their chin and cheeks,” where they have scent glands, Provoost says. (Read how cats know their names.)

Rubbing their faces on fellow felines “allows them to mix their scent together, ultimately culminating in a “colony scent’ in order for them to recognize who belongs in their group.” They greet us in the same way.

Overall, “the best advice is to read your cats’ body language,” Provoost says.

Zoran agrees, adding each cat is an individual with their own likes and dislikes, and and they are "not afraid to tell us what they prefer."

Ain't that the truth.