The secret of how cats twist in mid-air to land on their feet

When falling cats flip themselves the proper manner up earlier than they hit the bottom, they’ve a secret trick: a area of their backbone that’s distinctive at twisting.

“We in contrast the flexibleness of the thoracic backbone and lumbar backbone in cats, and we discovered that the thoracic backbone may be very versatile,” says Yasuo Higurashi at Yamaguchi College in Japan.

Cats famously all the time land on their toes. In the event you maintain a cat the wrong way up and drop it, the animal will rapidly wriggle in mid-air and land confidently on its toes.

Fairly how cats obtain this has been difficult scientists for over 100 years. Three principal concepts have emerged.

One is the propeller tail: the cat swings the tail a technique, inflicting its physique to rotate the opposite manner. “The tail appears to be the least vital, as a result of if it doesn’t have a tail it might probably nonetheless flip over,” says Greg Gbur on the College of North Carolina at Charlotte, writer of Falling Felines and Basic Physics.

One other thought, the bend-and-twist mannequin, proposes that the cat would bend its physique virtually right into a proper angle, then flip its entrance half a technique and the again half the opposite. This implies the entrance and rear legs each arrive on the appropriate place on the identical time.

Or the cat may rotate the entrance first after which the again in a tuck-and-turn. To do that, it might lengthen its rear legs whereas holding its entrance legs scrunched up, and twist its entrance half. Then it might swap so the entrance legs had been prolonged and the rear ones contracted, and twist its rear half. This may imply one pair of legs is accurately oriented earlier than the opposite.

To seek out out what cats actually do, Higurashi and his colleagues carried out two experiments. Within the first, they examined the spines of 5 deceased cats and twisted them to see how a lot every area may rotate with out breaking. They targeted on the thoracic backbone, from the center of the again, and the lumbar backbone, from the decrease again. It turned out that the thoracic backbone had a variety of movement 3 times that of the lumbar backbone.

Second, the group took high-speed video of two grownup cats being dropped from a top of 1 metre. In each instances, the cats completed rotating their fronts tens of milliseconds earlier than their rears.

“My normal impression has been that the bend-and-twist is a very powerful, however this paper truly makes me reassess a bit and provides slightly bit extra credence to the tuck-and-turn,” says Gbur. The extremely versatile thoracic backbone suggests to him that the entrance of the cat’s physique may be rotating extra. Moreover, within the reside experiments, “it actually does appear like the higher [front] a part of the physique is correctly oriented first”.

Gbur emphasises that the fashions aren’t mutually unique. “Physicists particularly like to look for easy fashions of how issues work, whereas nature tends to search for the best technique, which is probably not easy,” he says. “Cats are difficult creatures doing difficult motions.”

The examine additionally threw up an odd element. Each of the reside cats rotated to the proper as they fell: one did so each time, the opposite in six out of eight trials. Gbur says an viewers member at one in all his talks observed that the cats in his movies additionally appeared to show to the proper. “It appears to be like like, no less than anecdotally, cats appear to have a tough desire for which manner they twist,” he says. It’s not clear why; it could be that asymmetries within the placement of cats’ inner organs imply it’s simpler to show a technique than the opposite.