Cat righting reflex

{{Short description|Ability of cats to land on their feet}} [[File:Falling cat 1894.jpg|thumb|300px|''Falling Cat'' – images captured in a chronophotography by Étienne-Jules Marey (shown in the journal ''Nature'', 1894)]]

The '''cat righting reflex''' is a cat's innate ability to orient itself as it falls in order to land on its feet. The righting reflex begins to appear at 3–4 weeks of age, and is perfected at 6–9 weeks.<ref>{{cite journal |first1=Jeri A. |last1=Sechzera |first2=Susan E. |last2=Folsteina |first3=Eric H. |last3=Geigera |first4=Ronald F. |last4=Mervisa |first5=Suzanne M. |last5=Meehana |title=Development and maturation of postural reflexes in normal kittens |journal=Experimental Neurology |date=December 1984 |volume=86 |issue=3 |pages=493–505 |doi=10.1016/0014-4886(84)90084-0 |pmid=6499990 |s2cid=23606824 }}</ref> Cats are able to do this because they have an unusually flexible backbone and no functional clavicle (collarbone). The tail seems to help but cats without a tail also have this ability, since a cat mostly turns by moving its legs and twisting its spine in a certain sequence.<ref>{{cite web |url=http://helix.gatech.edu/Classes/ME3760/1998Q3/Projects/Nguyen/ |title=How does a Cat always land on its feet? |first=Huy D. |last=Nguyen |publisher=Georgia Institute of Technology, School of Medical Engineering |access-date=2007-05-15 |url-status=dead |archive-url=https://web.archive.org/web/20010410235503/http://helix.gatech.edu/Classes/ME3760/1998Q3/Projects/Nguyen/ |archive-date=2001-04-10 }}</ref>

While cats provide the most famous example of this reflex, they are not the only animal known to have a mid-air righting capability. Similar phenomena have been observed in other small vertebrates such as rabbits,<ref>{{Cite journal |last=Schönfelder |first=J. |date=March 1984 |title=The development of air-righting reflex in postnatal growing rabbits |journal=Behavioural Brain Research |volume=11 |issue=3 |pages=213–221 |doi=10.1016/0166-4328(84)90213-4 |issn=0166-4328 |pmid=6721914 }}</ref> rats,<ref>{{Cite journal |last1=Yan |first1=Xinping |last2=Okito |first2=Kazuyoshi |last3=Yamaguchi |first3=Takashi |date=March 2010 |title=Effects of superior colliculus ablation on the air-righting reflex in the rat |journal=The Journal of Physiological Sciences |volume=60 |issue=2 |pages=129–136 |doi=10.1007/s12576-009-0076-0 |issn=1880-6562 |pmid=20047100 |pmc=10717533 }}</ref> lizards, and certain invertebrate tailed arthropods (e.g. stick insects).<ref>{{Cite journal |last1=Jusufi |first1=Ardian |last2=Zeng |first2=Yu |last3=Full |first3=Robert |last4=Dudley |first4=Robert |date=19 September 2011 |title=Aerial Righting Reflexes in Flightless Animals |url=https://academic.oup.com/icb/article/51/6/937/617190 |journal=Integrative and Comparative Biology |volume=51 |issue=6 |pages=937–943 |doi=10.1093/icb/icr114 |pmid=21930662 |via=Oxford Academic}}</ref>

==Technique== thumb|Schematic animation of the motion involved [[File:BIOASTRONAUTICS RESEARCH Gov.archives.arc.68700.ogv|thumbtime=3:39|thumb|300px|start=3:39|end=4:09|Cats falling at normal gravity and with no gravity]] After determining down from up visually or with their vestibular apparatus (in the inner ear), cats twist themselves to face downward. They are able to accomplish this within the physical law of conservation of angular momentum with these key steps: #Bend in the middle so that the front half of their body rotates about a different axis from the rear half. #Tuck their front legs in to reduce the moment of inertia of the front half of their body and extend their rear legs to increase the moment of inertia of the rear half of their body so that they can rotate their front by as much as 90° while the rear half rotates in the opposite direction as little as 10°. #Extend their front legs and tuck their rear legs so that they can rotate their rear half further while their front half rotates in the opposite direction less. Depending on the cat's flexibility and initial angular momentum, if any, the cat may need to perform steps two and three repeatedly to complete a full 180° rotation.<ref name="Gymnastics">{{cite journal |archive-url=https://web.archive.org/web/19980528234354/http://www.usa-gymnastics.org/publications/technique/1997/2/twisting.html |archive-date=1998-05-28 |url=http://www.usa-gymnastics.org/publications/technique/1997/2/twisting.html |title=An insight into the Biomechanics of Twisting |first=Hardy |last=Fink |date=February 1997 |journal=Technique |volume=17 |number=2 |publisher=USA Gymnastics |access-date=2007-12-26}}</ref><ref name="CarlosICalle">{{cite book |url=https://books.google.com/books?id=AfXUjLT2eK8C |title=Superstrings and Other Things: A Guide to Physics |pages=106, 107 |first=Carlos I. |last=Calle |publisher=CRC Press |isbn=9780750307079 |access-date=2008-06-04|date=2001-10-10 }}</ref><ref>{{cite journal |last1=Kane |first1=Thomas |last2=Scher |first2=M. P. |year=1969 |title=A dynamical explanation of the falling cat phenomenon |journal=International Journal of Solids and Structures |volume=5 |issue=7 |pages=663–670 |doi=10.1016/0020-7683(69)90086-9 }}</ref>

==Terminal velocity== In addition to the righting reflex, cats have other features that reduce damage from a fall. Their small size, light bone structure, and thick fur decrease their terminal velocity. While falling, a cat spreads out its body to increase drag.<ref name="berkeley">{{cite web |url=http://www.ucmp.berkeley.edu/vertebrates/flight/gliding.html |title=Vertebrate Flight: Gliding and Parachuting |first=J.R. |last=Hutchinson |date=11 January 1996|publisher=University of California Museum of Paleontology |access-date=22 December 2016}}</ref> An average-sized cat with its limbs extended achieves a terminal velocity of about {{convert|60|mph|km/h|abbr=on}}, around half that of an average-sized man, who reaches a terminal velocity of about {{convert|120|mph|km/h|abbr=on}}.<ref>{{cite news |first1=D. |last1=Nasaw |title=Who, What, Why: How do cats survive falls from great heights? |date=25 March 2012 |newspaper=BBC News Online |url=https://www.bbc.com/news/magazine-17492802 |access-date=22 December 2016}}</ref> A 2003 study of feline high-rise syndrome found that cats "orient [their] limbs horizontally after achieving maximum velocity so that the impact is more evenly distributed throughout the body".<ref name="vnuk">{{cite journal |pmid=15363762 |doi=10.1016/j.jfms.2003.07.001 |volume=6 |issue=5 |title=Feline high-rise syndrome: 119 cases (1998–2001) |date=18 June 2003 |journal=J Feline Med Surg |pages=305–12 |first1=D. |last1=Vnuk |first2=B. |last2=Pirkić |first3=D. |last3=Matičić |first4=B |last4=Radisić |first5=M |last5=Stejskal |first6=T |last6=Babić |first7=M |last7=Kreszinger |first8=N |last8=Lemo |s2cid=40989939 |display-authors=2|doi-access=free |pmc=10822212 }}</ref>{{rp|311}}

==Injury== With their righting reflex, cats often land uninjured. However, this is not always the case, since cats can still break bones or die from extreme falls. In a 1987 study, published in the ''Journal of the American Veterinary Medical Association'', of 132 cats that were brought into the New York Animal Medical Center after having fallen from buildings, it was found that injuries per cat increased positively with altitude until a height of seven stories, at which point injuries decreased. One cat fell 40 stories without injury, having apparently bounced off a canopy and into a planter.<ref name=NYmed>{{cite web |url=http://www.straightdope.com/classics/a5_190.html |title=The Straight Dope: Do cats always land unharmed on their feet, no matter how far they fall? |website=The Straight Dope |date=1996-07-19 |first=Cecil |last=Adams |access-date=2008-06-04|archive-url=https://web.archive.org/web/20000815202738/http://www.straightdope.com/classics/a5_190.html|archive-date=2000-08-15}}</ref> The study's authors speculated that, after falling five stories, the cats reached terminal velocity, at which point they relaxed and spread their bodies out to increase drag. However, critics of the study have questioned the conclusion that mortality rates decrease as height increases due to survivorship bias; falls that resulted in instant death were not included as a deceased cat would not be brought to a vet.<ref name=NYmed/> A 2003 study of 119 cats concluded that "Falls from the seventh or higher stories, are associated with more severe injuries and with a higher incidence of thoracic trauma."<ref>{{cite journal|title=Feline high-rise syndrome: 119 cases (1998–2001)|first1=D.|last1=Vnuk|first2=B.|last2=Pirkić|first3=D.|last3=Matičić|first4=B.|last4=Radišić|first5=M.|last5=Stejskal|first6=T.|last6=Babić|first7=M.|last7=Kreszinger|first8=N.|last8=Lemo|date=1 October 2004|journal=Journal of Feline Medicine and Surgery|volume=6|issue=5|pages=305–312|doi=10.1016/j.jfms.2003.07.001|pmid=15363762|s2cid=40989939 |doi-access=free|pmc=10822212}}</ref>

==See also== * Buttered cat paradox – a humorous combination of two observations, the cat righting reflex and the buttered toast phenomenon * Falling cat problem – the mathematical problem of explaining the physics of the cat righting reflex * High-rise syndrome – veterinary terminology for injuries sustained by cats typically caused by falls from significant heights

==References== {{Reflist|30em}} __NOTOC__

==Further reading== *{{cite journal |last1=Arabyan |first1=A. |last2=Tsai |first2=D. |year=1998 |title=A distributed control model for the air-righting reflex of a cat |journal=Biol. Cybern. |volume=79 |issue=5 |pages=393–401 |doi=10.1007/s004220050488 |pmid=9851020 |s2cid=6443644 }} *{{cite journal |last=Diamond |first=J. |author-link=Jared Diamond |year=1988 |title=Why cats have nine lives |journal=Nature |volume=332 |issue=6165 |pages=586–587 |doi=10.1038/332586a0 |pmid=3357516|bibcode=1988Natur.332..586D |s2cid=4241224 }} *{{cite book | last=Gbur | first=Greg | title=Falling Felines and Fundamental Physics | publication-place=New Haven, CT | date=2019 | isbn=978-0-300-24907-1 | oclc=1122457477 | author-link=Greg Gbur}} *{{cite journal |author-link=Yiannis Laouris |last1=Laouris |first1=Y. |last2=Kalli-Laouri |first2=J. |author-link3=Peter Schwartze |last3=Schwartze |first3=P. |year=1990 |title=The postnatal development of the air-righting reaction in albino rats. Quantitative analysis of normal development and the effect of preventing neck-torso and torso-pelvis rotations |journal=Behavioural Brain Research |volume=37 |issue=1 |pages=37–44 |doi=10.1016/0166-4328(90)90070-U |pmid=2310493|s2cid=10542756 }} *{{cite journal |last1=Laouris |first1=Y. |last2=Kalli-Laouri |first2=J. |last3=Schwartze |first3=P. |year=1990 |title=The influence of altered head, thorax and pelvis mass on the postnatal development of the air righting reaction in albino rats |journal=Behav. Brain Res. |volume=38 |issue=2 |pages=185–190 |doi=10.1016/0166-4328(90)90016-8 |pmid=2363837 |s2cid=8325481 }}

==External links== * [https://arstechnica.com/science/2019/12/the-surprisingly-complicated-physics-of-why-cats-always-land-on-their-feet/ The surprisingly complicated physics of why cats always land on their feet] *[https://web.archive.org/web/20160420062227/http://video.nationalgeographic.com/video/cats_domestic_ninelives National Geographic video on the cat righting reflex] *[https://www.youtube.com/watch?v=RtWbpyjJqrU Slow Motion Flipping Cat Physics]

Category:Cat behavior Category:Reflexes Category:Articles containing video clips