Known is the saying that goes “a cat has nine lives”. In other latitudes they have similar sayings, for example in Europe a similar sentence attributes to this feline up to 7 lives (even though the Turkish version brings them down to “only” six).
What seems clear is that all cultures give the cat a survival bonus, without a doubt higher than that of other animals. The origin of these sayings has its roots in the surprising fact that many times cats fall from very high places without getting hurt.
If we analyze the injuries that these felines get after falling from different heights, we would see that in multiple cases these animals have been unscathed, or just had minor injuries after falling from tall buildings. What does the cat have to show this strange ability?
First of all, you have to bear in mind that cats have evolved to climb trees and take huge jumps to catch their prey. So, it is not surprising that nature has gifted their bodies with mechanisms to minimize injuries in case they fall.
Figure 1: The innate ability to jump from high places
In principle, it would seem pretty logic to think that injuries after falling off a building are more severe as height increases; but studies show that body damage is greater in falls from buildings 2-6 stories high than from higher places. Facts show that from the 6th story and up a series of physiological and physical mechanisms are turned on in order to protect the animal even more.
This was proven in a study that took place in New York in emergency room of a veterinary clinic where they followed up 132 cats that had fallen from different heights. 17 of them died while being transported to the hospital or had to be put down given the magnitude of the lesions. Of the remaining, 104 survived. Really a very high percentage.
A reason for this high ratio of survival has to be found in the fact that the cat reaches its maximum falling rate (terminal velocity) at the 5º floor. This speed is about 60 mph, meaning that, even if it falls from the 8th, 20th, or 32nd floor it won’t fall at a greater speed.
Figure 2: Injuries decrease in falls from 6th store and above
Based on the studies of Waring and Demling as well as Whitney and Mehlhoff
A person falling from that height would increase its speed as it falls. It would need 32 floors to reach its maximum falling rate which is about 120 mph. Just because of that, the ratio of survival of cats is bigger than humans when we fall from great heights. It’s not the same to weigh 8 pounds and fall at 60 mph than to weigh 150 pounds and fall at 120 mph. But, that would not make cats that different as many other pets are lighter than people.
Figure 3: Mortality rate between cats and humans after falling from different heights.
Based on the studies of Waring and Demling as well as Whitney and Mehlhoff
We have to bear in mind that cats, even when falling from a moderate height, always fall on their feet (thanks to a mechanism they master called straightening reflex). This reflex allow them to rotate around their backbone and position themselves in such a way that the first thing that touches the ground –cushioning the hit- are the paws. This flipping reflex is very interesting in itself as it seems to contradict the physical principle of conservation of angular momentum. Here a video that explains it all in more detail:
https://www.youtube.com/watch?v=RtWbpyjJqrU&t=308s
Figure 4: Straightening reflex. Source Wiki commons.
Author: Etienne-Jules Mare
Other animals, on the contrary, cannot control their body position when they fall. Their legs won’t be the first thing that hits the ground but other parts instead, such as the thorax or head, that won’t cushion the impact .
Besides, cats have a large body surface in proportion to their weight. This increases their chances of survival. A very important fact that we have to keep in mind is that until the cat reaches its terminal speed it is in a state of tension. Once that velocity is reached, its vestibular system stops being so stimulated and the animal extends its limbs in such a way that its body acts, to a certain point, like a parachute, thus minimizing the impact.
We should not forget that its legs are very muscular and able to absorb the impact of the fall to a large degree. Moreover, we should keep in mind that the front legs of the cat are not attached to the trunk by the clavicular bone, thus being more extensible and flexible. On the other hand, cat’s backbone has more vertebrae than ours. This allows for more flexibility.
When hitting the ground, the animal will have its legs flexed –just like when paratroopers flex their thighs and hips before touching the ground- this way the shocking force is largely dispelled in the soft tissues.
Other animals that weigh the same as the cat, such as small dogs, suffer bigger traumatisms than cats when falling from a great height. And that is because felines, like we have seen previously, have anatomical and physiological particularities which give them an advantage when playing around in heights.
So, in summary, cats have higher likelihood of survival when falling due to:
- Lower terminal velocity
- Straightening reflex
- High surface-body weight ratio
- Parachute effect
- Muscular legs
- Legs remain under the body, they do not spread out
- Absence of clavicular bone
- # of vertebrae
- Landing with flexed legs
The fact that cats have a better chance of not dying when falling from high places does not mean that we do not have to be careful and avoid this to happen. In fact, many times they do die or suffer severe injuries. So always keep them inside if living in a high apartment, and make sure windows are properly closed.
Bibliography:
- Feline Physics: Why Cats Can Survive Falls From Great Heights http://mentalfloss.com/article/29921/feline-physics-why-cats-can-survive-falls-great-heights
- Cats can survive falls from high places. Canadian veterinary medical association. November 2012.
http://www.canadianveterinarians.net/documents/cats-can-survive-falls-from-high-places
- Who, What, Why: How do cats survive falls from great heights. BBC news. March 2012.
http://www.bbc.com/news/magazine-17492802
4. Diamond, J. Why cats have nine lives. Nature, vol 332. April, 1988
http://www.nature.com/nature/journal/v332/n6165/pdf/332586a0.pd
5. Tortie, Maggie. Science of cat lapping. Anipal Times. 201
6. Whitney and C.J. Mehlhoff. High-rise syndrom in cats. J. Am. Vet. Med.Assoc.191, 1399-1403; 1987