In October 1894, during a meeting of the French Academy of Sciences, the famous physiologist Étienne-Jules Marey showed a series of photographs which caused a collective outcry among his colleagues. In the flurry of stories that followed, a conference attendee proclaimed that Marey had presented a scientific paradox that violated fundamental laws of how objects move.
At the center of the controversy was a cat. More specifically, a fall cat that had twisted in the air to land on its paws. The fall wasn’t the problem, nor was the touchdown. The scandal was triggered by what happened in the meantime.
For years, scientists assumed that cats could only land on their feet if they first launched from a surface. The idea was inspired by a physical concept known as conservation of angular momentum, which states that non-rotating bodies will not start unless an external force is applied. Without a push, a cat would have no leverage, nothing to entice it to roll over. But footage of Marey revealed a cat that started writhing after its descent had begun, pivoting, it seemed, on nothing at all.
In the decades that followed, scientists came up with many explanations for the puzzle, many of which totally missed the mark. Even today, “you’ll find people arguing” about the details of cats’ ass tricks, says Greg Gbur, a physicist at the University of North Carolina at Charlotte and author of Feline falls and fundamental physics. But experts can agree that cats are (unfortunately, maybe) not physics defying. They have simply evolved to tap into its deepest nuances, even when circumstances seem impossible to survive.
Baffled physicists at the French Academy thought of the cat’s angular momentum too simplistically, Gbur told me. The angular momentum can still be conserved in a spinning object – er, a cat – if half the body spins one way while the other half spins the other way, much like a pepper mill. The two parts of the body then act as fulcrums for each other, giving each other an equal and opposite pushing and twisting force. This is exactly what seems to happen in cats. “The skeleton of the cat is incredibly flexible,” says Barbro Filliquist, a veterinarian at UC Davis. Cats can arch their spine so strongly that they effectively split their bodies in half, almost like “having a knee joint on top of your back,” says David Hu, a mechanical engineer at Georgia Tech.
When a cat falls through the air upside down, the half with the head is usually the first to flip over. For this to happen, the front must rotate faster than the rear – a movement the cat probably initiates by folding its front paws towards its belly (similar to figure skaters pulling in their arms while executing a rapid rotation) while keep the hind legs apart. The cat then relaxes its front legs while pulling its back legs. This time the bit with the buttocks twists faster, bringing the rest of the body into the straight-up position. Meanwhile, the tail can, delightfully, act as a sort of helix, accelerating the rotations of the body. (It’s an unnecessary advantage, Gbur told me: Manx cats stick their landings very well.)
The flip happens “surprisingly fast,” says Hanno Essén, a physicist at the KTH Royal Institute of Technology, Sweden, who modeled the cat’s righting reflex. Cats can reorient themselves in a matter of meters and start the process in a fraction of a second. That very impulse helped Essén’s mischievous childhood cat, Moushe, land safely after falling from a window about 40 to 50 feet off the ground.
Despite their aerodynamic antics, cats still face tremendous risk when falling from high perches, especially as modern buildings in urban centers have become taller. At Schwarzman Animal Medical Center in New York, nearly a quarter of pet-related trauma cases over the past seven years have been recorded as a “fall from a height”, according to Carly Fox, one of the senior veterinarians. from AMC. In the worst cases, the so-called high rise syndrome can seal felines with nosebleeds, broken mouths, collapsed lungs, broken legs, and even ruptured organs.
The farther cats fall, the worse off they are generally, at least up to a point. A handful of research, including some from AMC, has suggested that beyond six or seven floors, the injury rate may level off or even reverse. That, scientifically, is “weird,” says Rhett Allain, a physicist at Southeastern Louisiana University who has written about the phenomenon for Wired. “You never see” the higher the better. “”Some of the data may be biased by owners taking their cats to the vet, and it’s pretty hard to ethically confirm; other studies have found quite opposite results. With such sparse and conflicting data, “we just don’t know,” says California emergency and critical care veterinarian Michael Kato.
If the motive is legit, it would fit with the shocking resilience of some cats at great heights. Gbur once saw a cat take an inconsequential fall 100 feet from a tree; Fox recently treated one who survived a fall from 19 stories. A cat named Sabrina plunged 32 stories into concrete and lived to tell the tale. Another, Jommi, reportedly fell 26 stories, pierced the roof of a tent and was found grooming herself nearby, completely unscathed. “I’ve seen cats that have fallen seven, eight, nine, 10 stories, and they have lacerations, maybe a broken leg, but those are fixable,” says Christine Rutter, emergency and care vet. intensive care at Texas A&M University. Studies show that survival rates for tall height syndrome in cats consistently exceed 90%, “which is savage for me, given the ERs and ICUs I work in,” says Sophia Amirsultan, an emergency and critical care veterinarian at North Carolina State University.
The secret may involve the cats slipping through another flaw in physics. During the first few dozen meters of descent, a cat’s body will continue to accelerate, increasing the impact it will feel when it finally hits the ground. It’s quite a difficult affair for cats that overturn about two to five stories high. Just past this fifth floor, however, an 11-pound cat will reach its terminal velocity of about 60 miles per hour; no matter how high its starting point is, its final thump will be no worse. The implications are crazy: there may be no real limit, Allain told me, to the altitude from which a cat can dive and survive.
Reaching terminal velocity can feel pleasantly weightless, and might even cause the cat’s brain to “stop freaking out” and relax its paws, Rutter told me. The impact still happens, but it’s a bit more sproingy and a bit more evenly distributed across the cat’s body. This could explain why Kato discovered that the types of injuries he and his colleagues see at heights of seven stories and above tend to be more concentrated in the torso and jaw than in the limbs.
Rabbits, too, seem to have a pretty decent righting reflex; Some types of geckos, scientists have found, can propel themselves safely to the ground by whipping their very thick tails. But maybe only house cats achieve the perfect combo: an incredible sense of balance, to quickly sense when they need to turn around, plus lightning-fast reflexes, a bendable back and super stretchy limbs to realize it, Mairin Balisi, a paleontologist at the Raymond M. Alf Museum of Paleontology in California, told me. Cats, which have evolved to be agile and tree-dwelling, can even be helped by their smooth, slightly shock-absorbing physique, Amirsultan told me. Dogs, several vets have told me, tend not to fare so well after a fall. Even some larger cat species may not always stick on landing, Balisi said. (If it was, she added, The Lion King would never have worked.)
I asked Gbur if humans could learn to mimic cats’ gyroscopic turns. No doubt, he told me, we already have. The best divers and gymnasts can be terribly cat-like in their flips; NASA has also turned to cats to teach astronauts how to frolic in gravity-free space. But the cats “will always do better,” Gbur told me, although they may not enjoy the trip. Perhaps no one knew better than Marey, the OG purveyor of fallen cat photos: A Nature An article published the month after the conference could not help but note the “expression of offended dignity” carried by its subject, forever immortalized on film.
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