Dynamics of Cats

On caturday here at Supernova Condensate, I like to endeavour to bring you the very best combination I can of cats and science. Or at least, the very best combination I can find with a few minutes using Google. Interestingly, this is not even remotely difficult an endeavour, which would perhaps indicate the need for studies correlating cats and scientists.

This rather wonderful piece of vintage research (partially funded by NASA!) investigates the body kinematics of falling cats in quite some detail. In the very first paragraph of this entertaining little paper the authors make a point of the fact that a cat landing on its feet, even if released from an upside down position, has received serious attention by a number of scientists in the past. Regrettably though, the only copy of this paper I could find appears to be incomplete and lacking the references page, so I’m having to take their word for that – though if it’s any consolation, you can find a slightly hilarious video of a self-righting cat on the Discovery website.

Seriously, they get unashamedly technical in this study. It’s not just fluff, this paper is chock full of mechanics, mostly in the form of angular momentum equations (an article on the Guardian website uses the delightful term “a mathematical abstraction of a cat”). They approximated a cat body, as you can see in the figure to the left here, as two connected cylinders and modelled the exact process the cat’s body has to go through to, as the legend goes, always land on its feet.

It’s unfortunate that my copy of this seems to stop abruptly on the 8th page or so – I have pages 663-669 plus two image pages, even though according to the citation generator the article is only pages 663-666. Curious.

This leaves me to have to speculate on exactly why these scientists may have been studying falling cats, and precisely why NASA may have been involved. About the only thing that really springs to mind is the fact that had Beagle 2, for one notable example, been even half as good at landing as your average kitty cat, it might have proven rather more successful.

(With apologies to Steinn Sigurðsson for the frankly unavoidable reference to his blog!)


Kane, T., & Scher, M. (1969). A dynamical explanation of the falling cat phenomenon International Journal of Solids and Structures, 5 (7), 663-666 DOI: 10.1016/0020-7683(69)90086-9


About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
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