Cats’ Flexible Spines Help Them Pull Off the Mid‑Air Twist — and Land on Their Feet

They say cats have nine lives. This myth thrives on their extraordinary ability to land on their feet, even from seemingly impossibly high heights. Case in point: a one-year-old cat from Boston named Sugar, who survived a 19-story fall in 2012 with only minor injuries, Time Magazine reported.

Now, research published in the journal The anatomical file shows that this innate ability can at least partly be explained by variations in spinal flexibility, a physiological advantage that allows felines to twist in the air.

Learn more: Your cat may share the same cancer genes as you and offer treatment clues

The aerial righting superpower of cats

The ability of cats to reorient themselves mid-fall and land on their feet is known as “air righting.” This behavior allows them to absorb the impact of landing, resulting in less serious injuries than a similar fall, for example to a human or dog. However, the exact mechanisms behind aerial righting remain a mystery.

To find out what particular movements may be involved, a team of researchers from Yamaguchi University, Japan, examined the spines of five cat cadavers and compared the maximum torque (or force), range of motion, neutral zone (i.e., the range in which twisting occurs with minimal resistance), and stiffness of the middle (thoracic) and lower (lumbar) spines. Overhead righting was then recorded and analyzed in a pair of live cats, which were dropped into a soft cushion from a height of approximately 3 feet (1 meter).

Step 1: Test Failure

The first part of the experiment involved destructive failure testing, a process that pushes a product – or, in this case, the spines of five cat corpses – to the point of failure in order to determine its upper limits. This approach allowed the team to calculate the peak torque and range of motion of the thoracic spine (from the base of the neck to the bottom of the ribs) and the lumbar spine (from the bottom of the ribs to the pelvis).

The results show that the thoracic spine is more flexible, with a much greater range of motion and a wider neutral zone of 47°. In contrast, the lumbar spine had higher levels of stiffness and had no neutral zone. Its range of motion was about one-third that of the thoracic spine. It did, however, have a higher maximum force (or maximum torque) level, which was roughly double that of the thoracic.

Step 2: Observe the behavior in action

The second part of the experiment involved observing the behavior in action. For this, two cats were dropped eight times from a height of 3 feet (1 meter) and recorded using a high-speed camera.

The event happened in a blink-and-you’ll-miss-it moment, happening in just milliseconds. Yet the records show that rotation of the upper body (anterior trunk) consistently occurred “significantly” earlier than that of the lower body (posterior trunk). While the average landing time for each cat was 324 and 342 milliseconds, respectively, the time difference between the end of the two rotations was 94 and 72 milliseconds.

The falling cat problem

The researchers say the study suggests that during the overhead straightening, the trunk rotates “sequentially.” The upper trunk rotates first and the lower trunk rotates second, an action made possible by the flexibility of their thoracic spine and the rigidity of their lumbar spine.

This fits the “legs in, legs out” model, the researchers said in the study. This theory suggests that cats extend their hind limbs, causing the fore trunk to rotate, then retract their hind limbs and extend their fore limbs, causing the hind trunk to rotate in the same direction.

But the results are not conclusive: “the debate on the problem of cat falls remains”, explain the authors in the study. “Alternative explanations remain possible.”

Learn more: Be careful what you say: your cat may be listening to you

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