This matches my kitty.

I noticed her preference because if I lie on my left-hand side, she is a very happy little spoon and uses my arm as a pillow.

If I lie on my right-hand side, kitty is confused. She will take extra preparatory rotations hoping that one more turn will be enough for the problematic situation to resolve. After some hard stares, maybe an annoyed huff, she will reluctantly curl-up as a face-to-face non-spoon.

I should take some data. I've got enough cats to border crazy-cat-lady territory. I had the impression that they sleep in random positions -- basically, whatever shape they were in when the urge to nap came upon them.

I'll keep an eye on them and see if they have a preference that I'd missed. It won't be all that useful -- if nothing else, the specific preferred sleeping places of my house could have more to do with my layout than any underlying mechanism in the cat. But I'd kinda like to know if there has been something staring me in the face all this time and I just didn't put it together.

I feel this publication could have used many more figures

>To address this question, we analyzed 408 publicly available YouTube videos featuring a single cat in a clearly visible sleeping position while lying on one side, with an uninterrupted sleep duration of at least 10 seconds and full-body visibility from head to hind legs.

408 videos, showing bias towards leftward pose. They claim to have removed the mirrored videos from their samples.

I prefer the paper on cat chirality:

https://blog.dimview.org/math/2017/07/28/cat-chirality.html

Though his dataset is only a single cat he fails to reject the null hypothesis. But you can use the included graphics to plot the chirality of your own pet.

With my dog, the only thing I've noticed is that no matter which chirality he initially choses, he seems to need to switch it up after a while.

The author declared no competing interests, but I bet they are a certified cat lover and therefore biased

They literally got paid to watch cat videos on the Internet.

This is hilarious. While I work, one of my cats loves to share my desk chair and sleep between me and the backrest (forcing me to sit closer to the front edge). I've noticed she favors lying on her left flank there, and she is, in fact, sleeping behind me like this right now.

(Anecdotal, but +1.)

On the other hand, she's one of a bonded pair and I'll sometimes see her and her sister sleeping curled next to each other with more varied chirality. Maybe a trusted friend outweighs this effect?

I prefer chirality for cats, they sleep either clockwise, counterclockwise, or possibly corkscrew.

Did they check if the outcome is different on the southern hemisphere?

I think this is the opposite for lions? I'm only going by the fact that the Buddha is shown sleeping on his right side all of the time and that this is called the lion pose (not the same as the yoga lion pose). He slept on his right side in the same way male lions sleep on their right side.

(I first learned this because I was researching why when I meditated on my right side I would sometimes have hallucinogenic visions, but not on my left side - it was a surprise to come across this fact about the Buddha)

In humans, sleeping on the left side is said to be beneficial for heartburn: https://www.health.harvard.edu/diseases-and-conditions/whats... I wonder if similar digestive benefits might be at play in cats, instead of or in addition to the paper's proposed explanation.

This is objectively the best paper of 2025 so far, according to the metric of number of adorable kitties depicted.

Wow. Is this really a Cell article? Congrats to the authors.

Publishing in cell gets you a tenure track.

My cat does the same thing. Whenever I lie on my side, they slowly roll over to snuggle against the same side every time. If I face the "wrong" way, they fidget and squirm for a while until they settle in.

Reading this study made me realize that cats are actually very good at finding balance.

I have an ambisleptous cat, who regularly changes positions.

Am I crazy or are the cats pictured under the graph swapped? The cat under the "leftward" bar is curled the right and the cat under the "rightward" bar is curled to the left. Did they just decide that egocentrism in directions doesn't apply to cats?

Meanwhile my parents keep sending me pictures of our cat sleeping belly up. How does he fit in this model?

> we analyzed 408 publicly available YouTube videos

Does YouTube provide a way to search and download videos for such research purposes? Or does one have to use some tool that works around YouTube’s mechanisms that prevent downloading?

Ig Nobel Prize contender here.

Cleaned up url: https://www.cell.com/current-biology/fulltext/S0960-9822(25)...

My cat Emacs's signature move is the unlaterilized sploot, and I recently caught him sleeping on his back in an unlaterilized upside-down sploot!

https://en.wikipedia.org/wiki/Splooting

My tuxedo cat Napoleon is much more dignified, presenting a distinguished catloaf, while crossing his front paws with aristocratic grace.

https://en.wikipedia.org/wiki/Cats_and_the_Internet#Catloaf

Wait till I tell my daughter that someone's job is watching cat videos on the internet for science!

I really like the vibes of this paper, very short, and centered around a very household topic. Sounds very inviting to junior researchers to start contributing about literally anything that they are familiar with and arouses a deep curiosity.

Previously submitted: https://news.ycombinator.com/item?id=44371307