A new study details how cats always land on their feet

It is well established that when cats fall, they are able to land perfectly most of the time, maneuvering gracefully to right themselves before they hit the ground. Now, researchers at Japan’s Yamaguchi University have advanced our understanding of this unusual ability, focusing on the mechanical properties of cat spines.

What they found, as detailed in a recent study in the journal The Anatomical Record, is that these firm landings are due in part to the fact that a cat’s thoracic region is much more flexible than its lumbar region.

While the cat’s ability to spin in the air with nothing to push back seems to defy the laws of physics, it is instead a complex corrective maneuver. To find out how to do this, researchers in the new study first analyzed the spines of five dead cats, separated their thoracic and lumbar regions and then subjected them to mechanical tests to measure their flexibility, strength and resistance to rotation. In another experiment, researchers used high-speed cameras to film two cats falling onto a soft pillow.

From subsequent analyses, as reported in Phys.org, the team noted that what makes cats so good at falling is their spines, which are not uniformly flexible. In particular, the thoracic region is very flexible: it can rotate about 50 degrees with very little effort. In contrast, the lumbar region is stiffer and acts as a stabilizer.

Therefore, when straightening in the air, cats first rotate their head and front legs toward the ground because their thoracic spine is flexible, and then the entire back of the body follows. The stiffer lumbar region acts as a kind of anchor, allowing the cat to rotate the front without losing control.

The results of the new study indicate that the complex mid-air correction maneuver performed by cats occurs in a precise sequence. “During air adjustment, anterior torso rotation was completed earlier than posterior torso rotation,” the study says. “These results suggest that trunk rotation during air tuning in cats occurs sequentially, with the anterior trunk rotating first followed by the posterior trunk, and that a flexible thoracic spine and rigid lumbar spine in axial torsion are relevant for this behavior.”

In addition to revealing the secret of cats’ ability to fall “upright,” the researchers conclude that the findings could help veterinarians treat spinal injuries, and even lead to the development of more flexible robots.

This story originally appeared in WIRED Italia and was translated from Italian.