Why Falling Cats Always Seem To Land On Their Feet

An anonymous reader quotes a report from the New York Times: In a paper, published last month in the journal The Anatomical Record, researchers offered a novel take on falling felines. Their evidence suggests new insights into the so-called falling cat problem, particularly that cats have a very flexible segment of their spines that allows them to correct their orientation midair. […] People have been curious about falling cats perhaps as long as the animals have been living with humans, but the method to their acrobatic abilities remains enigmatic. Part of the difficulty is that the anatomy of the cat has not been studied in detail, explains Yasuo Higurashi, a physiologist at Yamaguchi University in Japan and lead author of the study. […]

Modern research has split the falling cat problem into two competing models. The first, “legs in, legs out,” suggests that cats correct their falling trajectory by first extending their hind limbs before retracting them, using a sequential twist of their upper and then lower trunk to gain the proper posture while in free fall. The second model, “tuck and turn,” suggests that cats turn their upper and lower bodies in simultaneous juxtaposed movements. […]

The researchers found that the feline spine was extremely flexible in the upper thoracic vertebrae, but stiffer and heavier in the lower lumbar vertebrae. The discovery matches video evidence showing the cats first turn their front legs, and then their lower legs. The results suggest the cat quickly spins its flexible upper torso to face the ground, allowing it to see so that it can correctly twist the rest of its body to match. “The thoracic spine of the cat can rotate like our neck,” Dr. Higurashi said.

Experiments on the spine show the upper vertebrae can twist an astounding 360 degrees, he says, which helps cats make these correcting movements with ease. The results are consistent with the “legs in, legs out” model, but definitively determining which model is correct will take more work, Dr. Higurashi says. The results also yielded another discovery: Cats, like many animals, appear to have a right-side bias. One of the dropped cats corrected itself by turning to the right eight out of eight times, while the other turned right six out of eight times.