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So here's the premise.

  1. A cat reaches its terminal velocity after around 10meters of free fall.
  2. A cat can survive a landing from a speed equal to its terminal velocity.
  3. Therefore a cat can survive a fall from any height.

This seems actually quite feasible and would be tremendous if it holds some truth in the majority of cases. I guess there are plenty of animals that can survive their own terminal velocity but a cat somehow just seems too close to home, too familiar.

I also realise that this is a difficult claim to prove or falsify as throwing cats out of windows for experimental purposes doesn't seem the most moral thing. Maybe a collated record of accidents? But that's not too scientific.

Kit Sunde
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    It depends on whether you mean is it possible, or can you expect a given cat to survive a fall. All I know is that my ex had a cat fall from the window of her high rise apartment and it splattered on the sidewalk. – psusi May 20 '11 at 19:08
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    A good experiment would be dropping a cat from a balloon at the edge of the atmosphere :) Would it survive? – Chris Dennett May 21 '11 at 01:24
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    @ChrisDennett Doesn't sound like a good experiment to me, since the cat could suffocate or freeze to death. Just establish the terminal velocity and don't go any higher than you need to reach it. – RomanSt Jul 30 '12 at 09:48
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    http://i.imgur.com/LsqVr.gif – NullUserException ఠ_ఠ Dec 07 '12 at 18:25
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    I'm aware of a kitten that limped a bit after going skydiving from the 27th floor--obviously enough to reach terminal velocity. It comes down to what the cat lands on. – Loren Pechtel Oct 04 '14 at 18:34
  • @ChrisDennett, no it would suffocate first, a fall from that distance would take more than 5 minutes, most of which would be in atmosphere to thin for the cat to breath. – John Apr 12 '17 at 14:05
  • No; outer space lacks the air they need to survive. – Cees Timmerman Jun 17 '17 at 13:36

3 Answers3

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As was brought up on in Is the use of parachutes supported by peer-reviewed papers? Where Andrew Grimm pointed to a study from 1987 which is widely reported (it's paywalled so I can't check myself) to say that not only do cats survive terminal velocity, but that their chance of survival increase over some shorter distances. That said the actual study cites that the cats falling from buildings had a 90% survival rate (after treatment), but also a lot of injuries. From the abstract:

High-rise syndrome was diagnosed in 132 cats over a 5-month period. The mean age of the cats was 2.7 years. Ninety percent of the cats had some form of thoracic trauma. Of these, 68% had pulmonary contusions and 63% had pneumothorax. Abnormal respiratory patterns were evident clinically in 55%. Other common clinical findings included facial trauma (57%), limb fractures (39%), shock (24%), traumatic luxations (18%), hard palate fractures (17%), hypothermia (17%), and dental fractures (17%). Emergency (life-sustaining) treatment, primarily because of thoracic trauma and shock, was required in 37% of the cats. Nonemergency treatment was required in an additional 30%. The remaining 30% were observed, but did not require treatment. Ninety percent of the treated cats survived.

The Straight Dope details how far the cats fell which mentions terminal velocity:

But here's the weird part. When the vets analyzed the data they found that, as one would expect, the number of broken bones and other injuries increased with the number of stories the cat had fallen — up to seven stories. Above seven stories, however, the number of injuries per cat sharply declined. In other words, the farther the cat fell, the better its chances of escaping serious injury.

The authors explained this seemingly miraculous result by saying that after falling five stories or so the cats reached a terminal velocity — that is, maximum downward speed — of 60 miles per hour. Thereafter, they hypothesized, the cats relaxed and spread themselves out like flying squirrels, minimizing injuries. This speculation is now widely accepted as fact.

Although the Straight Dope is also careful to point out that perhaps the reason why more terminal velocity cats appear to survive is that the one that didn't land so gracefully wasn't brought into the emergency room and as such the statistics could be skewed.

A more recent study from 2004 cites the previous study as well as several others. The cats in this study had a higher survival rate:

High-rise syndrome was more frequent during the warmer period of the year. 96.5% of the presented cats, survived after the fall.

It also go into a rather deep detail on various injuries sustained by the cats in all the studies, also stating cats don't reach terminal velocity until after the 6th floor and reaches the same conclusion as the previous studies:

This substantiates the theory that cats falling at least seven stories flex their limbs so that truncal injuries are more common, while cats falling from distances lower than seven stories extend their limbs, the consequence being a greater incidence of limb fractures.

Somewhat interestingly and related it cites a study on high rise syndrome in dogs from 1993 that says dogs cannot survive a fall from more than 6 stories.

If we want to investigate further perhaps we should ask Disney to record a movie on the life of wild cats.

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Kit Sunde
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    So... the lesson is to put the cat in a bag before dropping it from a high-rise. Got it. – MrHen May 20 '11 at 14:59
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    Cats may indeed survive falls of over six stories with fewer injuries than those falling under six stories, but the science that people cite in their possible explanations is inaccurate. If a cat reaches terminal velocity of about 60 mph as stated in all sources, then by using the Acceleration constant **g** of 9.8 m/sec/sec, the cat will reach terminal velocity in 2.7 seconds or longer. That happens at a minimum of approximately 116 feet or 8 to 10 stories. This would tend to contradict the terminal velocity/relaxation theorists. –  Oct 04 '14 at 04:46
  • @FlipJohnson have you accounted for air friction? Cats slow their acceleration as they approach the terminal velocity, they don't just suddenly get affected by friction at 60 mph. – raptortech97 Oct 04 '14 at 15:00
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    @raptortech97 That would increase the needed height before terminal velocity is reached. – Taemyr Oct 06 '14 at 12:40
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    It amazes me that an answer like this one, which has thoroughly been debunked, would continue to accumulate so many upvotes on a site that calls itself "skeptics." :-) I suspect this is an example of a myth that so many people want to be true that they overlook the fallacies used to support it. – whuber Jul 24 '16 at 21:46
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    @whuber Your comment lacks any substance, feel free to contribute some. – Kit Sunde Jul 24 '16 at 21:47
  • @Kit I did: see [the answer I posted in 2015.](http://skeptics.stackexchange.com/a/26418/24698) – whuber Jul 24 '16 at 21:52
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    @whuber Apart from you assuming selection bias can completely explain away the survival rate, I don't see how that answer is saying anything different. It's a possibility but you don't have evidence beyond your own assertions. Saying "Thoroughly debunked" is a stretch don't you think? – Kit Sunde Jul 24 '16 at 22:15
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    Kit, the selection bias is not an assumption: it's a fact. The burden is on the researcher to use a valid protocol and demonstrate it was valid. Unless you can offer a study that has overcome that bias--I looked and was unable to find one--you have nothing to back up this "feline high rise" theory. Isn't that what scepticism is all about? Insisting that conclusions be based on solid evidence and sound reasoning? – whuber Jul 25 '16 at 12:55
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    @whuber You misunderstand the nature of this site. I can't take your opinion on what studies have bias because the site doesn't allow original research, you have to actually find literature that convincingly has put in the work. It's not our jobs to dismiss studies and do original research, it's our job to give answers based on what's in the literature. Also if you want to talk skepticism then its a fallacy to conclude something is wholesale false because you think there is bias. It's not a binary notion. It's possible that bias can both skew the results and that there is evidence for it. – Kit Sunde Jul 25 '16 at 13:05
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    I have not conducted *any* "original research"! I have merely pointed out the fatal flaw in the authorities you and others are relying on to draw your conclusions. If the purpose of this site is merely to pit one authority against another, maybe it should be called something more accurate, such as "apologists," "references," or "received wisdom" :-). – whuber Jul 25 '16 at 13:09
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    @whuber Your perceived fatal flaw. Without putting in the work it's opinion. But it's okay, I'm not going to continue this line of repeating the same thing. It has been pointed out elsewhere that the sites name is confusing to people, take it up in meta if you want but it has been like this forever and it will be futile. – Kit Sunde Jul 25 '16 at 13:13
  • to get accuracy 96.5% one needs at least 200 cats.... – Matas Vaitkevicius Sep 15 '16 at 14:15
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    @whuber - I'm not sure that your answer so much debunked this explanation as put it into the "not proven" category. Stating that there is a selection bias casts the conclusions into doubt, but that's not the same as, say "it's been shown that cats do dies from those falls." What you showed is that animal hospital numbers would normally not give any indication of cats surviving vs cats not. – PoloHoleSet Nov 10 '16 at 15:40
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    @Andrew That sounds like a fair assessment. Thank you for the clarification. – whuber Nov 10 '16 at 16:20
  • @whuber - having said that, I understand your comment about a "not proven" answer continuing to garner up-votes. – PoloHoleSet Nov 10 '16 at 16:41
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    So yes some will survive (if treated). However there is survivor bias in the data, so no conclusion can be made about safest hight. – ctrl-alt-delor Apr 09 '17 at 13:16
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The literature on this goes back to the original Whitney & Mehlhaff paper, which studied "the traumatic injuries sustained by any animal falling from a substantial height.”

Whitney, Wayne O., Cheryl J. Mehlhaff, High-rise Syndrome in Cats, JAVMA, Vol. 191, No.11, PP. 1309-1403, 12/1/87.

This study documents injuries and outcomes in 132 cats that had fallen two or more stories and were taken to the authors (New York City veterinarians) for treatment. Its main objective is to explain why and how most of these cats survived and to describe the nature of their injuries. The authors were surprised at one observation and speculated as to its reason:

... the rate of injury was approximately linear up to a distance fallen of approximately 7 stories. Surprisingly, these injury rates did not continue to increase with falls of >7 stories, and the fracture rate decreased. ... A possible explanation for this phenomenon ... is ... during free fall, cats have a unique ability to quickly minimize postural torque, rotation, and tumbling to maintain a feet-first landing position. An averaged-sized (4-kg), horizontally outstretched cat maximizes drag and achieves a terminal velocity of approximately 60 mph after falling approximately 5 stories. Cats falling from higher heights do not accelerate beyond this speed, but continue to fall at terminal velocity. It was surprising, however, that the fracture rate decreased in cats falling >7 floors. To explain this, we speculate that until a cat achieves terminal velocity it experiences acceleration and reflexively extends its limbs, making them more prone to injury. After terminal velocity has been reached, however, ... the cat might relax and orient its limbs more horizontally, much like a flying squirrel.

There exists a far better explanation and it requires no such (wholesale) speculation: the cats treated by veterinarians are not representative of cats who fall out of buildings. There is a high likelihood of a blatant selection bias: cats who fell but were uninjured were not admitted to this study; cats who fell, were injured, and survived had good chances of entering the study; and cats who wound up as bloody smears on the sidewalk would never have appeared. This alone casts doubt on all general conclusions about "high-rise syndrome" based on this study (and comparable subsequent ones).

Further evidence in support of this explanation is the authors' observation en passant that

The syndrome is seen predominantly in young cats...

These would have the greatest chances of survival among the general cat population. Older cats who fell generally didn't make it to the vets' office.

Given the obvious physical relationship between height of fall and shock of impact, we can therefore predict that the cats in this study who fell more than a few stories were the lucky ones, not the typical ones. Thus, there is no valid way to draw conclusions from trends seen in this study to any actual phenomenon.

Both this and a subsequent study report 90% survival. This, of course, is the survival rate among the cats who did not die before reaching the vet. (Kapatkin, Amy S., David T. Matthiesen, Feline High-Rise Syndrome, Compendium for Continuing Education, Vol. 13, No. 9, pp. 1389-1403, 9/91.) What should we conclude from this? Only that if you can get your injured cat alive to the vet within a couple of hours after its fall, it will have excellent chances of living due to the vet's skills in emergency diagnosis and treatment.

The only conclusion about high-rise syndrome that can be supported by this evidence is that cats who survive the veterinarian's treatment could have fallen from practically any height. The other conclusions that people have drawn--the "parachute" or "flying squirrel" theories, that cats will survive falls from any height, etc.--are not supported by this study (nor by any followup studies I had been able to locate in 2006 when I investigated this matter).

Afterward

Depending on your mood, you may find it either amusing or disheartening that pure speculation can quickly enter textbooks as received fact. A popular and well-respected physics textbook (Halliday, Resnick, and Walker, Fundamentals of Physics, 7th Edition, Part I, p. 123. J. Wiley & Sons, 2005) not only incorporates the Whitney & Mehlhaff explanation wholesale, it amplifies it and makes it more plausible by adding details that nobody could possibly have observed:

According to calculations, ... a cat must fall about six floors to reach terminal speed. Until it does so, [the gravitational force exceeds the drag force] and the cat accelerates downward because of the net downward force. ... Because the cat also senses the acceleration, it is frightened and keeps its feet underneath its body, its head tucked in, and its spine bent upward, making [the effective cross-sectional area of its body] small, [the terminal velocity] large, and injury likely.

However, if the cat does reach [the terminal velocity] during a longer fall, the acceleration vanishes and the cat relaxes somewhat, stretching its legs and neck horizontally outward and straightening its spine (it then resembles a flying squirrel). These actions increase [the effective cross-sectional area of its body] and thus also, by [the drag coefficient equation], the drag. The cat begins to slow because now [the drag force exceeds the gravitational acceleration] (the net force is upward), until a new, smaller [terminal velocity] is reached. The decrease in [the terminal velocity] reduces the possibility of serious injury on landing. Just before the end of the fall, when it sees it is nearing the ground, the cat pulls its legs back beneath its body to prepare for the landing.

It's a good story, but it's merely a statement of faith, not science.

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whuber
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    I'm not sure it's fair to say the more speculative explanation is a "statement of faith, not science". It does make more assumptions, which makes it less parsimonious under Occam's Razor, but the speculative scenario is internally consistent, i.e. if the cat did react this way, that would be the likely outcome. In fact, the speculation opens up more avenues for research (e.g. modelling and testing such a scenario, observing how a cat actually acts in a controlled environment, etc) than the more dismissive but parsimonious appeal to survival bias. – ROBOKiTTY Oct 05 '16 at 08:45
  • That said, it's unfortunate that the untested speculation has been taken at face value and accepted in some sources before follow-up research could be conducted. – ROBOKiTTY Oct 05 '16 at 08:52
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    I believe the last word of the first paragraph of the long quote near the end should be "likely" rather than "unlikely" – Glen_b Oct 28 '17 at 07:37
  • Thanks, @Glen_b. You must be correct, so I have removed the "un". – whuber Oct 28 '17 at 13:22
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In the parachute question, the accepted answer noted that a few individuals who fell 5,000 metres or even 10,000 metres have survived.

If a human can fall that far, it's plausible that a cat falling that far can potentially survive. But there's a big difference between "can" and "definitely will".

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Andrew Grimm
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    I know this is an old answer, but probably it should now be converted to a comment or improved, as it does not meet the standards of the site anymore. – nico Oct 04 '14 at 07:55