Contrary to popular belief, falling cats do not always land on their feet. In fact, every day cats sustain serious injuries from falling out of open windows, off balconies, and from rooftops. Cats do not fear heights and will often leap after a bird or a butterfly only to find themselves falling through the air. The trauma sustained from a fall of over two stories (24 to 30 feet) is known as high-rise syndrome.
If a cat falls a short distance, he can usually right himself and land on his feet. If he falls more than one or two floors, however, he may sustain injury. Although he can right himself, his legs and feet cannot absorb the shock.
Cats have exceptional coordination and balance and a flexible musculoskeletal system. They are normally able to orient their bodies in space in such a way as to land on all four limbs. This is what happens when a cat falls:
However, whether or not a cat lands on his feet depends on several factors, including the distance he falls and the surface on which he falls.
Cats have the ability to right themselves in midair thanks to the vestibular apparatus. This is a tiny fluid-filled organ housed deep in their inner ear that is responsible for their remarkable balance. It is composed of tiny chambers and canals lined with millions of sensitive hairs and filled with fluid and minute floating crystals. When cats move, the fluid shifts, giving readings on the body's position – similar to the instrument in an airplane called the "artificial horizon" that tells the pilot the position of the plane's wings in relation to the horizon.
When a cat falls, the vestibular apparatus becomes active and helps the cat register which way is up. This allows the cat to right himself in midair by adjusting the orientation of the body. The righting reflex appears in a kitten at three to four weeks and is perfected by seven weeks.
The uniqueness of the cat's skeleton is another reason they can right themselves. A cat does not have a collarbone and the bones in his backbone have more mobility than in many other animals. So cats have free movement of their front legs and they can bend and rotate their bodies like a pretzel.
In a study from the Journal of the American Veterinary Medical Association, two veterinarians examined 132 cases of cats that had fallen out of high-rise windows. On average, the cats fell 5.5 stories, but 90 percent survived, although many suffered severe injuries. The number of broken bones and injuries increased with the number of stories the cat had fallen – up to seven stories. Above seven stories, however, the number of injuries declined. In other words, the farther the cat fell, the better were his chances of escaping injury.
The reason for this may be that after falling five stories or so, cats reach a terminal velocity. The velocity or speed of a falling body does not increase forever because the rate of increase in speed is interrupted by air resistance. A skydiver reaches a terminal velocity of around 130 to 140 mph after about 30 seconds of free-falling. Cats reach terminal velocity much sooner at a speed of 60 mph.
It's instinctive for both humans and animals to tense their muscles when free-falling, which makes them more susceptible to injury. When cats land before reaching top speed, they are rigid and flexed and prepared for the landing. This results in most of the force impacting the parts of the body that hit initially. However, after reaching terminal velocity, cats relax their muscles and spread themselves out like flying squirrels. This allows the impact of the fall to be spread across a larger surface area.
Cats are good at surviving falls. However, there are many examples of cats falling only a short distance and acquiring severe injuries. The best way to keep your cat safe is to make sure there are no high-up open windows in your home without heavy screens. Make sure screens are intact and strong as cats insistent on going outside have been known to slash through thin screens. Finally, unscreened balconies and upstairs porches should be off-limits to your cat.