Why do falling cats always seem to land on their feet? Scientists have been arguing about the precise mechanism for a very long time—since at least 1700, in fact—conducting all manner of experiments to pin down what’s going on. The research continues, with a paper published in the journal The Anatomical Record reporting on new experiments to analyze the flexibility of feline spines.
We covered this topic in-depth in 2019, when University of North Carolina, Charlotte, physicist Greg Gbur published his book, Falling Felines and Fundamental Physics. For a long time, scientists believed that it would be impossible for a cat in free fall to turn over. That’s why French physiologist Etienne-Jules Marey’s 1894 high-speed photographs of a falling cat landing on its feet proved so shocking to Marey’s peers. But Gbur has emphasized that cats are living creatures, not idealized rigid bodies, so the motion is more complicated than one might think.
Over the centuries, scientists have offered four distinct hypotheses to explain the phenomenon. There is the original “tuck and turn” model, in which the cat pulls in one set of paws so it can rotate different sections of its body. Nineteenth-century physicist James Clerk Maxwell offered a “falling figure skater” explanation, whereby the cat tweaks its angular momentum by pulling in or extending its paws as needed. Then there is the “bend and twist,” in which the cat bends at the waist to counter-rotate the two segments of its body. Finally, there is the “propeller tail,” in which the cat can reverse its body’s rotation by rotating its tail in one direction like a propeller.
At the time, Gbur told Ars that, while all those different motions play a role, he thought that the bend-and-twist motion was the most important. “When one goes through the math, that seems to be the most fundamental aspect of how a cat turns over,” he said. “But there are all these little corrections on top of that: using the tail, or using the paws for additional leverage, also play a role.” This latest paper has Gbur rethinking that conclusion, according to his recent blog post, giving a bit more credence to the tuck-and-turn mechanism.
A spinal twist
A team of Japanese scientists removed the spines from five donated cat cadavers, preserving the ligaments and spinal discs and separating the thoracic and lumbar sections. Then they placed the sections into a twisting device to see how much force was required to twist them, and the limits of how far the sections could twist. They also took high-speed photographs of two cats in free fall after being dropped (eight times each).
The results: The upper section could twist further than the lower section, plus there was a “sweet spot” of sorts at about the 50-degree twist mark, where there was essentially no resistance to the twisting motion. That sweet spot did not exist for the lower section of the spine, supplying evidence for the “tuck and turn” hypothesis. “The flexibility of the upper part of the spine strongly supports this perception that the cat turns to get its head right-side up first and indicates that its biology is even tailored to make this as easy as possible,” Gbur wrote. Furthermore, the high-speed photographs clearly showed the waist kinking for a bend-and-twist motion, but with one of the rear legs extended and front paws tucked in, more typical of a tuck-and-turn mechanism.
The researchers were also surprised to find that the two cats they photographed while falling showed a marked preference to turn to the right: One turned to the right every time, while the other turned to the right six out of eight times. “Apparently there is some natural tendency for cats to twist right, even though they clearly can go both ways,” Gbur wrote. “My best guess at this point is that some asymmetric placement of internal organs may make it just a little easier to go one way than another.”
The debate will likely continue, per Gbur, in part because it’s so difficult to analyze the motion of falling cats, given that all the photo sequences to date have been taken from a single angle. “It would be really nice in the future to see someone take a multi-angle sequence that could be converted into a 3D model,” he wrote. “I suspect we might learn even more about how a cat performs its twist.”
The Anatomical Record, 2026. DOI: 10.1002/ar.70165Digital Object Identifier (DOI) (About DOIs).
