For Cats, a Big Gulp With a Tiny Touch of the Tongue | Hacker News Reader

For Cats, a Big Gulp With a Tiny Touch of the Tongue

nytimes.com

72 pointshornokplease23 comments

"The project required no financing. The robot that mimicked the cat’s tongue was built for an experiment on the International Space Station, and the engineers simply borrowed it from a neighboring lab."

It's mindblowing enough that it took until the year 2010 to figure out how cats drink water. How do we live in a modern world with all the unimaginable wonders of science and integrated circuits and space travel, with more people studying exotic data from space probes and particle accelerators than there were scientists of any variety 500 years ago, and yet until now a cat drinking water was a complete mystery to us? The fact that figuring it out was a side project using borrowed equipment is a punchline.

I couldn't believe I believed the cat hair on tongue myth for the past 8 years I've lived with my cat... But now that you mention all of human kind not figuring it out either, I feel better.

This is a wonder of the modern world: Extreme high-speed digital cameras, the kind of stuff that Harold Edgerton became renowned for a mere fifty years ago, are now so cheap, easy to use, and sensitive that some guys at MIT can afford to aim one at their cats for extended periods of time on a whim.

Back in Edgerton's day you had to take ultra-high-speed photographs using extremely bright strobe lighting. I don't know for sure that he never photographed a cat lapping, but I can't imagine that the typical cat was happy to sit around drinking when strobes were going off and a high-speed film spool was cranking nearby. Plus, there was probably a crazy backlog of other, more serious things to film. So it was probably hard to collect enough data to be sure you knew what was happening.

I helped a lab shop for one of these high-speed cameras a few years back. They were not cheap, but they were cheaper than some cars, and they've probably gotten even cheaper since. When these things get to the point that we can all afford one, we are going to have some serious fun.

All hail the semiconductor optics folks! Buy one a drink today! ;)

Calculating the balance between opposing gravitational and inertial forces is yet another reason why cats are awesome.

Calculating the balance between opposing gravitational and inertial forces is yet another reason why evolution is awesome.

Fixed it for you.

edit: Really? Downvotes for promoting evolution? Just because I did it in an amusing way?

No, more likely because you did it using a Slashdot meme, which, while some might find it funny, most here find it obnoxious.

Don't forget "classy."

It's interesting that this is quite different from how dogs drink: http://bethesignal.org/blog/2009/06/13/how-do-dogs-drink-wat... They scoop up the water with their tongues by curling it backwards.

It looks like there's also a column of water involved, like with the cats.

> The lapping frequency should be the weight of the cat species, raised to the power of minus one sixth, and multiplied by 4.6.

I wonder how mass^(-1/6) has the same unit as frequency.

I'm guessing the NYTimes journalist didn't quite follow the math in the paper

I'd presume that the 4.6 has some units attached to it that the reporter missed. (Which unfortunately is important since we're given no other indication what units of mass are to be used.)

1/6 sort of makes sense though. Mass is directly proportional to volume, and it's probably the length of the tip of the tongue which is important, so there's a cube root right there. Throw in a square root for good measure (those tend to show up in physics problems) and invert it since the frequency presumably decreases w/r/t mass and you're at mass^-1/6.

I wonder if this will take next year's Ig Nobel prizes in both veterinary medicine and physics...

My cat is too lazy for math. She lays next to water bowl with her chin resting on the edge and her paw dangling into the water, then just rotates her wrist to bring her wet paw up to her mouth and licks the water off her paw. Repeat.

>The cat laps four times a second — too fast for the human eye to see but a blur

I'm pretty sure that's not true.

I mean, the 4 Hz thing is probably true, but my eyes have little trouble discerning 4 Hz.

think about four numbers, or words, or pictures of cat tongues flashed in a second. Still think you'd be able to "see" those. You'll for sure see movement but not have time to discern details

well it would very much depend on 4 Hz of what. It's really easy to notice flickering white light at 4 Hz but it's alot harder to see something that moves a long distance back an forth at 4 Hz.

I can see my cat move her tongue back and forth four times a second just fine.

The fact that they lap at precisely the right frequency... Darwin's theory is so perfect, and I just figured out how to put in words why it is. feedback.

Feedback really is king.

I agree that evolution did play the crucial part in developing the drinking method for cats, which is now part of their instinct, but the precise frequency can be learned during their lifetime, it does not have to be instinctive. Cats train their drinking technique daily for long stretches of time, so they have plenty of chance to optimize their drinking frequency. And the thing is, that is feedback as well: cats, being quite impatient, try to drink water as fast as they can, so they try to move their tongues faster, only to discover that they are spending more time getting their drink, so they slow down their tongues again, and get more water.

The only way to find out is have a cat drink at reduced (not zero) gravity.

New mission for NASA: "Cat on the moon."

"I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a cat on the Moon and watching him drink."

Huh... if it is evolutionarily ingrained, then that means that Dogs would be far better space-pets.

I would hazard evolution had to play at least a role in the frequency thing- you need some special developments to do something like this 4 times a second. You're right though, it could be part behavioral.

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