View source for Animal locomotion

{{Short description|Self-propulsion by an animal}}
{{For|the Eadweard Muybridge study|Animal Locomotion{{!}}''Animal Locomotion''}}
[[File:Bioluminescent beetle Elateroidea - animated.gif|thumb|A [[beetle larva]] performing a [[rectilinear locomotion]].]]

In [[ethology]], '''animal locomotion''' is any of a variety of methods that [[animal]]s use to move from one place to another.<ref name=EB>{{cite web|url=http://www.britannica.com/EBchecked/topic/345861/locomotion|title=Animal locomotion|publisher=Encyclopædia Britannica|access-date=December 16, 2014}}</ref> Some modes of locomotion are (initially) self-propelled, e.g., [[running]], [[swimming]], [[jumping]], [[flight|flying]], hopping, soaring and [[gliding]]. There are also many animal species that depend on their environment for transportation, a type of mobility called passive locomotion, e.g., sailing (some [[jellyfish]]), [[ballooning (spider)|kiting]] ([[spider]]s), [[rolling]] (some [[beetle]]s and spiders) or riding other animals ([[phoresis]]).

Animals move for a variety of reasons, such as to [[foraging|find food]], a [[mating system|mate]], a suitable [[microhabitat]], or to [[escape response|escape predators]]. For many animals, the ability to move is essential for survival and, as a result, [[natural selection]] has shaped the locomotion methods and mechanisms used by moving organisms. For example, [[animal migration|migratory animals]] that travel vast distances (such as the [[Arctic tern]]) typically have a locomotion mechanism that costs very little energy per unit distance, whereas non-migratory animals that must frequently move quickly to [[escape reflex|escape predators]] are likely to have energetically costly, but very fast, locomotion.

The anatomical structures that animals use for movement, including [[cilia]], [[leg]]s, [[wing]]s, [[arm]]s, [[fin]]s, or [[tail]]s are sometimes referred to as ''locomotory organs''<ref>{{cite book | last = Beckett | first = B. S. | title = Biology: A Modern Introduction | publisher = Oxford University Press | date = 1986 | pages = 307 | url = https://books.google.com/books?id=IrCTghhgKh0C&q=locomotory+organs+of+animals&pg=PA1 | isbn = 9780199142606 }}</ref> or ''locomotory structures''.<ref>{{Citation | last1 = Lindsay | first1 = Everett H. | last2 = Fahlbusch | first2 = Volker | last3 = Mein | first3 =  Pierre | title = European Neogene Mammal Chronology | publisher = Springer Science & Business Media | series = Nato Science Series A | volume = 180 | year = 2013 | pages = 658 | url = https://books.google.com/books?id=Wi8BCAAAQBAJ&q=%22locomotor+structure%22&pg=PA455 | isbn = 9781489925138}}</ref>

==Etymology==
The term "locomotion" is formed in English from Latin ''loco'' "from a place" (ablative of ''locus'' "place") + ''motio'' "motion, a moving".<ref>{{cite web|url=http://www.etymonline.com/index.php?term=locomotion|title=Locomotion|access-date=December 16, 2014|publisher=Online Etymology Dictionary}}</ref>
<!--we could mention names like planthopper, mudskipper, sugarglider, treecreeper, roadrunner, backswimmer, pond skater as being derived from means of loco, perhaps, with suitable refs-->

The movement of whole body is called locomotion

==Aquatic==
{{Main|Aquatic locomotion}}

===Swimming===
[[File:Dolphinsurfresize.jpg|thumb|Dolphins surfing]]
{{further|Nekton|fish locomotion}}
In water, staying afloat is possible using buoyancy. If an animal's body is less dense than water, it can stay afloat. This requires little energy to maintain a vertical position, but requires more energy for locomotion in the horizontal plane compared to less buoyant animals. The [[Drag (physics)|drag]] encountered in water is much greater than in air. Morphology is therefore important for efficient locomotion, which is in most cases essential for basic functions such as [[predation|catching prey]]. A fusiform, [[torpedo]]-like body form is seen in many aquatic animals,<ref name="Gaston">{{cite journal|author=Gaston, K.A., Eft, J.A. and Lauer, T.E.|year=2016|title=Morphology and its effect on habitat selection of stream fishes|journal=Proceedings of the Indiana Academy of Science|volume=121|issue=1|pages=71–78}}</ref><ref name="Dewar">{{cite journal|author1=Dewar, H.  |author2=Graham, J.|year=1994|title=Studies of tropical tuna swimming performance in a large water tunnel-kinematics|journal=Journal of Experimental Biology|volume=192|issue=1|pages=45–59|doi=10.1242/jeb.192.1.45|pmid=9317308|bibcode=1994JExpB.192...45D }}</ref> though the mechanisms they use for locomotion are diverse.

The primary means by which [[fish]] generate [[thrust]] is by oscillating the body from side-to-side, the resulting wave motion ending at a large [[Caudal fin|tail fin]]. Finer control, such as for slow movements, is often achieved with thrust from [[pectoral fins]] (or front limbs in marine mammals).  Some fish, e.g. the spotted ratfish (''Hydrolagus colliei'') and batiform fish (electric rays, sawfishes, guitarfishes, skates and stingrays) use their pectoral fins as the primary means of locomotion, sometimes termed [[labriform swimming]].  [[Marine mammal]]s oscillate their body in an up-and-down (dorso-ventral) direction.
Other animals, e.g. penguins, diving ducks, move underwater in a manner which has been termed "aquatic flying".<ref name="Walker">{{cite journal|last1=Walker |first1=J.A. |last2=Westneat |first2=M.W.|year=2000|title=Mechanical performance of aquatic rowing and flying|journal=Proceedings of the Royal Society of London B: Biological Sciences|volume=267|issue=1455|pages=1875–1881|doi=10.1098/rspb.2000.1224|pmid=11052539|pmc=1690750}}</ref>  Some fish propel themselves without a wave motion of the body, as in the slow-moving seahorses<!--which rely on [[camouflage]] among seaweeds--> and ''[[Gymnotus]]''<!--which need a straight back to generate stable electric fields-->.<ref name=Sfakiotakis>{{cite journal|last1=Sfakiotakis |first1=M. |last2=Lane |first2=D.M. |last3=Davies |first3=J.B.C. |year=1999 |title=Review of Fish Swimming Modes for Aquatic Locomotion |url=http://www.mor-fin.com/Science-related-links_files/http___www.ece.eps.hw.ac.uk_Research_oceans_people_Michael_Sfakiotakis_IEEEJOE_99.pdf |journal=IEEE Journal of Oceanic Engineering |volume=24 |issue=2 |pages=237–252 |doi=10.1109/48.757275 |url-status=dead|archive-url=https://web.archive.org/web/20131224091124/http://www.mor-fin.com/Science-related-links_files/http___www.ece.eps.hw.ac.uk_Research_oceans_people_Michael_Sfakiotakis_IEEEJOE_99.pdf |archive-date=2013-12-24 |bibcode=1999IJOE...24..237S |citeseerx=10.1.1.459.8614 |s2cid=17226211 }}</ref>

Other animals, such as [[Cephalopoda|cephalopods]], use [[Aquatic locomotion#Jet propulsion|jet propulsion]] to travel fast, taking in water then squirting it back out in an explosive burst.<ref name="Young">{{cite web |url=http://tolweb.org/accessory/Cephalopod_Jet_Propulsion?acc_id=2060 |title=Cephalopod jet propulsion|author1=Young, R.E.  |author2=Katharina M. Mangold, K.M. |publisher=Tree of Life |access-date=October 16, 2016}}</ref>  Other swimming animals may rely predominantly on their limbs, much as humans do when swimming. Though life on land originated from the seas, terrestrial animals have returned to an aquatic lifestyle on several occasions, such as the fully aquatic [[cetacean]]s, now very distinct from their terrestrial ancestors.

Dolphins sometimes ride on the [[bow wave]]s created by boats or surf on naturally breaking waves.<ref name="Fish">{{cite journal |author1=Fish, F.E.  |author2=Hui, C.A. |year=1991 |title=Dolphin swimming–a review |journal=Mammal Review |volume=21 |issue=4 |pages=181–195 |doi=10.1111/j.1365-2907.1991.tb00292.x|bibcode=1991MamRv..21..181F }}</ref>

===Benthic===
[[File:scallop jump.svg|thumb|[[Scallop]] in jumping motion; these bivalves can also swim.]]

[[Benthic]] locomotion is movement by animals that live on, in, or near the bottom of aquatic environments. In the sea, many animals walk over the seabed.  [[Echinoderms]] primarily use their [[tube feet]] to move about. The tube feet typically have a tip shaped like a suction pad that can create a vacuum through contraction of muscles. This, along with some stickiness from the secretion of [[mucus]], provides adhesion. Waves of tube feet contractions and relaxations move along the adherent surface and the animal moves slowly along.<ref name="Smith">{{cite journal|author=Smith, J. E. |year=1937 |title=The structure and function of the tube feet in certain echinoderms |journal=Journal of the Marine Biological Association of the United Kingdom |volume=22 |issue=1 |pages=345–357 |doi=10.1017/S0025315400012042 |bibcode=1937JMBUK..22..345S |s2cid=55933156 |url=http://sabella.mba.ac.uk/966/01/The_structure_and_function_of_the_tube_feet_in_certain_echinoderms.pdf |url-status=dead|archive-url=https://web.archive.org/web/20131115215341/http://sabella.mba.ac.uk/966/01/The_structure_and_function_of_the_tube_feet_in_certain_echinoderms.pdf |archive-date=2013-11-15 }}</ref> Some sea urchins also use their spines for benthic locomotion.<ref>{{cite web |last1=Chenoweth |first1=Stanley |title=The Green Sea Urchin in Maine, Fishery and Biology|url=http://www.maine.gov/dmr/science-research/species/seaurchin/green_sea_urchin_general_summary.html |publisher=State of Maine |access-date=4 October 2016 |date=1994}}</ref>

Crabs typically walk sideways<ref name="Sleinis">{{cite journal |title=Locomotion in a forward walking crab |author1=Sleinis, S.  |author2=Silvey, G.E. |journal=Journal of Comparative Physiology A |volume=136 |issue=4 |year=1980 |doi=10.1007/BF00657350 |pages=301–312|s2cid=33455459 }}</ref> (a behaviour that gives us the word [[wikt:crabwise|''crabwise'']]). This is because of the articulation of the legs, which makes a sidelong gait more efficient.<ref name="Vidal-Gadea">{{cite journal |title=Skeletal adaptations for forwards and sideways walking in three species of decapod crustaceans |author1=A. G. Vidal-Gadea |author2=M. D. Rinehart |author3=J. H. Belanger |journal=Arthropod Structure & Development |volume=37 |issue=2 |year=2008 |pmid= 18089130 |pages=179–194 |doi=10.1016/j.asd.2007.06.002|bibcode=2008ArtSD..37...95V }}</ref> However, some crabs walk forwards or backwards, including [[Raninidae|raninids]],<ref>{{cite web |title=Spanner crab ''Ranina ranina'' |url=http://www.dpi.nsw.gov.au/fisheries/recreational/saltwater/sw-species/spanner-crab |publisher=[[New South Wales Department of Primary Industries]] |access-date=January 4, 2009 |year=2005 |work=Fishing and Aquaculture}}</ref> ''[[Libinia emarginata]]''<ref>{{cite journal |title=Muscular anatomy of the legs of the forward walking crab, ''Libinia emarginata'' (Decapoda, Brachyura, Majoidea) |author1=A.G. Vidal-Gadea  |author2=Belanger, J.H.|journal=Arthropod Structure & Development |volume=38 |issue=3 |year=2009 |pmid=19166968 |pages=179–194 |doi=10.1016/j.asd.2008.12.002|bibcode=2009ArtSD..38..179V }}</ref> and ''[[Mictyris platycheles]]''.<ref name="Sleinis"/> Some crabs, notably the [[Portunidae]] and [[Matutidae]], are also capable of swimming,<ref name="Ng">{{cite journal|journal=Raffles Bulletin of Zoology |year=2008 |volume=17 |pages=1–286 |title=Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world |author=Ng, P.K.L. |author2=Guinot, D |author3=Davie, P.J.F. |url=http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf |url-status=dead|archive-url=https://web.archive.org/web/20110606061453/http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf |archive-date=2011-06-06 }}</ref> the [[Portunidae]] especially so as their last pair of walking legs are flattened into swimming paddles.<ref name="Weis">{{cite book |author=Weis, J.S. |year=2012 |title=Walking sideways: the remarkable world of crabs |publisher=Cornell University Press |location=Ithaca, NY |pages=63–77|isbn=978-0-8014-5050-1 |oclc=794640315}}</ref>

A stomatopod, ''[[Nannosquilla decemspinosa]]'', can escape by rolling itself into a self-propelled wheel and somersault backwards at a speed of 72 rpm.  They can travel more than 2 m using this unusual method of locomotion.<ref name="Srour">{{cite web|access-date=October 29, 2016|title=Mantis Shrimp (Crustacea: Stomatopoda)|date=July 13, 2011|author=Srour, M.|publisher=Bioteaching.com|url=http://bioteaching.com/mantis-shrimp-crustacea-stomatopoda/|archive-date=December 29, 2019|archive-url=https://web.archive.org/web/20191229041906/http://bioteaching.com/mantis-shrimp-crustacea-stomatopoda/|url-status=dead}}</ref>

==Aquatic surface==
[[File:Velella Bae an Anaon.jpg|thumb|upright|''[[Velella]]'' moves by sailing.]]
{{Main|Animal locomotion on the water surface}}

''[[Velella]]'', the by-the-wind sailor, is a cnidarian with no means of propulsion other than [[sailing]]. A small rigid sail projects into the air and catches the wind. ''Velella'' sails always align along the direction of the wind where the sail may act as an [[aerofoil]], so that the animals tend to sail downwind at a small angle to the wind.<ref>{{cite book |title=Principles of Animal Locomotion |first=R. |last=McNeill Alexander |author-link=R. McNeill Alexander |publisher=Princeton University Press |year=2002 |isbn=978-0-691-08678-1}}</ref>

While larger animals such as ducks can move on water by floating, some small animals move across it without breaking through the surface. This surface locomotion takes advantage of the [[surface tension]] of water. Animals that move in such a way include the [[water strider]]. Water striders have legs that are [[hydrophobic]], preventing them from interfering with the structure of water.<ref name="Gao">{{cite journal|author1=Gao, X.  |author2=Jiang, L.|year=2004|title=Biophysics: water-repellent legs of water striders|journal=Nature|volume=432|issue=7013|pages=36|doi=10.1038/432036a|pmid=15525973|bibcode=2004Natur.432...36G|s2cid=32845070|doi-access=free}}</ref>  Another form of locomotion (in which the surface layer is broken) is used by the [[basilisk lizard]].<ref name="NationalGeographic">{{cite web|publisher=National Geographic News|year=2010|access-date=February 20, 2016|title=How "Jesus Lizards" walk on water|url=http://news.nationalgeographic.com/news/2004/11/1116_041116_jesus_lizard_2.html|archive-url=https://web.archive.org/web/20060127194900/http://news.nationalgeographic.com/news/2004/11/1116_041116_jesus_lizard_2.html|url-status=dead|archive-date=January 27, 2006}}</ref>

==Aerial==
{{see also|Aeroplankton}}

===Active flight===
[[File:Gonepteryx rhamni Twisting Wings in Courtship Flight.jpg|thumb|A pair of [[Gonepteryx rhamni|brimstone butterflies]] in flight. The female, above, is in fast forward flight with a small [[angle of attack]]; the male, below, is twisting his wings sharply upward to gain [[lift (force)|lift]] and fly up towards the female.]]
{{Main|Flight|Flying and gliding animals}}

Gravity is the primary obstacle to [[flight]]. Because it is impossible for any organism to have a density as low as that of air, flying animals must generate enough [[Lift (force)|lift]] to ascend and remain airborne. One way to achieve this is with [[wing]]s, which when moved through the air generate an upward [[lift (force)|lift force]] on the animal's body. Flying animals must be very light to achieve flight, the largest living flying animals being birds of around 20 kilograms.<ref name=Campbell/> Other structural adaptations of flying animals include reduced and redistributed body weight, fusiform shape and powerful flight muscles;<ref name="Hedenstrom">{{cite journal |author1=Hedenstrom, A.  |author2=Moller, A.P. |year=1992 |title=Morphological adaptations to song flight in passerine birds: a comparative study |journal=Proceedings of the Royal Society of London B: Biological Sciences |volume=247 |issue=1320 |pages=183–187 |doi=10.1098/rspb.1992.0026|bibcode=1992RSPSB.247..183H |s2cid=84788761 }}</ref> there may also be physiological adaptations.<ref name="Sacktor">{{cite journal |author=Sacktor, B. |year=1975 |title=Biochemical adaptations for flight in the insect |journal=Biochemical Society Symposium |volume=41 |issue=41 |pages=111–131|pmid=788715 }}</ref> Active flight has [[convergent evolution|independently]] evolved at least four times, in the [[insect flight|insect]]s, [[pterosaur]]s, [[bird flight|bird]]s, and [[bat]]s. Insects were the first taxon to evolve flight, approximately 400 million years ago (mya),<ref name="Selleh">{{cite web |title=Insects evolved flight as plants grew taller |date=November 7, 2014 |author=Salleh, A. |publisher=ABC |access-date=October 14, 2016 |url=http://www.abc.net.au/science/articles/2014/11/07/4121879.htm}}</ref> followed by pterosaurs approximately 220 mya,<ref>{{Cite journal|last1=Barett|first1=Paul M.|last2=Butler|first2=Richard J.|last3=Edwards|first3=Nicholas P.|last4=Milner|first4=Andrew R.|date=September 26, 2007|title=Pterosaur distribution in time and space: an atlas|url=https://epub.ub.uni-muenchen.de/12007/1/zitteliana_2008_b28_05.pdf|journal=Zitteliana|volume=B28|pages=61–107|issn=1612-4138}}</ref> birds approximately 160 mya,<ref name=NatureBird>{{cite journal |author1=Pascal Godefroit |author2=Andrea Cau |author3=Hu Dong-Yu |author4=François Escuillié |author5=Wu Wenhao |author6=Gareth Dyke |year=2013 |title=A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds |journal=Nature |volume= 498|issue= 7454|pages= 359–62 |doi=10.1038/nature12168 |bibcode = 2013Natur.498..359G |pmid=23719374|s2cid=4364892 }}</ref> then bats about 60 mya.<ref name="Chiropteran">{{cite web |title=Vertebrate flight: Chiropteran flight |url=http://www.ucmp.berkeley.edu/vertebrates/flight/bats.html |access-date=October 14, 2016}}</ref>{{better source|date=October 2016}}

===Gliding===
{{Main|Flying and gliding animals|Aerial locomotion in marine animals}}

Rather than active flight, some (semi-) arboreal animals reduce their rate of falling by [[gliding (flight)|gliding]].  Gliding is heavier-than-air flight without the use of [[thrust]]; the term "volplaning" also refers to this mode of flight in animals.<ref>{{Citation|title=volplane|url=https://www.thefreedictionary.com/volplane|work=The Free Dictionary|access-date=2022-01-06}}</ref>  This mode of flight involves flying a greater distance horizontally than vertically and therefore can be distinguished from a simple descent like a parachute. Gliding has evolved on more occasions than active flight.  There are examples of gliding animals in several major taxonomic classes such as the invertebrates (e.g., [[gliding ant]]s), reptiles (e.g., [[banded flying snake]]), amphibians (e.g., [[flying frog]]), mammals (e.g., [[sugar glider]], [[squirrel glider]]).

[[File:Pink-wing flying fish.jpg|thumb|200px|right|Flying fish taking off]]

Some aquatic animals also regularly use gliding, for example, [[flying fish]], octopus and squid.  The flights of flying fish are typically around 50&nbsp;meters (160&nbsp;ft),<ref name="Piper 2007">[[Ross Piper]] (2007), ''Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals'', [[Greenwood Press (publisher)|Greenwood Press]].</ref> though they can use updrafts at the leading edge of waves to cover distances of up to {{convert|400|m|abbr=on}}.<ref name="Piper 2007"/><ref name="Flying Fish, Exocoetidae">{{Cite web|date=2010-04-11|title=Flying Fish &#124; National Geographic|url=https://www.nationalgeographic.com/animals/fish/facts/flying-fish|archive-url=https://web.archive.org/web/20210228002821/https://www.nationalgeographic.com/animals/fish/facts/flying-fish|url-status=dead|archive-date=February 28, 2021|access-date=2022-01-06|website=Animals|language=en}}</ref>  To glide upward out of the water, a flying fish moves its tail up to 70 times per second.<ref name=history>{{cite journal|last=Kutschera |first=U. |year=2005 |title=Predator-driven macroevolution in flyingfishes inferred from behavioural studies: historical controversies and a hypothesis |journal=Annals of the History and Philosophy of Biology |volume=10 |pages=59–77 |url=http://www.evolutionsbiologen.de/flyingfishes.pdf |url-status=dead|archive-url=https://web.archive.org/web/20070820072237/http://www.evolutionsbiologen.de/flyingfishes.pdf |archive-date=2007-08-20 }}</ref>
Several oceanic [[squid]], such as the [[Todarodes pacificus|Pacific flying squid]], leap out of the water to escape predators, an adaptation similar to that of flying fish.<ref>{{cite journal |author=Packard, A. |year=1972 |title=Cephalopods and fish: the limits of convergence |journal=Biol. Rev. |volume=47 |issue=2 |pages=241–307 |doi=10.1111/j.1469-185x.1972.tb00975.x|s2cid=85088231 }}</ref> Smaller squids fly in shoals, and have been observed to cover distances as long as 50 m. Small fins towards the back of the mantle help stabilize the motion of flight. They exit the water by expelling water out of their funnel, indeed some squid have been observed to continue jetting water while airborne providing thrust even after leaving the water. This may make flying squid the only animals with jet-propelled aerial locomotion.<ref>{{cite journal|author=Maciá, S. |author2= Robinson, M.P. |author3=Craze, P. |author4=Dalton, R. |author5=Thomas, J.D. |title=New observations on airborne jet propulsion (flight) in squid, with a review of previous reports.|journal=J. Molluscan Stud. |year=2004 |volume=70 |issue= 3 |pages=297–299 |doi=10.1093/mollus/70.3.297|doi-access=free }}</ref> The [[neon flying squid]] has been observed to glide for distances over {{convert|30|m|abbr=on|sigfig=1}}, at speeds of up to {{convert|11.2|m/s|ft/s mph|abbr=on}}.<ref>{{cite web |title=Scientists Unravel Mystery of Flying Squid |url=http://voices.nationalgeographic.com/2013/02/20/scientists-unravel-mystery-of-flying-squid/ |archive-url=https://web.archive.org/web/20141215072724/http://voices.nationalgeographic.com/2013/02/20/scientists-unravel-mystery-of-flying-squid/ |url-status=dead |archive-date=December 15, 2014 |publisher=National Geographic |access-date=4 October 2016 |date=20 February 2013}}</ref>

===Soaring===
Soaring birds can maintain flight without wing flapping, using rising air currents. Many gliding birds are able to "lock" their extended wings by means of a specialized tendon.<ref>{{cite book | last=Loon | first=Rael | title=Sasol Birds - The Inside Story | publisher=New Holland Published | location=City | year=2005 | isbn=978-1-77007-151-3 | page=20}}</ref>  Soaring birds may alternate glides with periods of soaring in [[lift (soaring)|rising air]]. Five principal types of lift are used:<ref name=Welch>{{cite book | last=Welch | first=John | title=Van Sickle's Modern Airmanship | publisher=McGraw-Hill | year=1999 | pages=856–858 | isbn=978-0-07-069633-4}}</ref> [[thermal]]s, [[ridge lift]], [[lee waves]], [[Convergence zone|convergences]] and [[dynamic soaring]].

Examples of soaring flight by birds are the use of:
*Thermals and convergences by [[bird of prey|raptor]]s such as [[vulture]]s
*Ridge lift by [[gull]]s near cliffs
*Wave lift by migrating birds<ref>[Report of use of wave lift by birds by Netherlands Institute for Ecology]{{full citation needed|date=June 2023}}</ref> 
*Dynamic effects near the surface of the sea by [[albatross]]es

===Ballooning===
[[Ballooning (spider)|Ballooning]] is a method of locomotion used by spiders. Certain silk-producing [[arthropod]]s, mostly small or young spiders, secrete a special light-weight [[Gossamer (spider silk)|gossamer silk]] for ballooning, sometimes traveling great distances at high altitude.<ref>{{Cite book|last=Heinrichs|first=Ann|url=https://www.worldcat.org/oclc/54027960|title=Spiders|date=2004|publisher=Compass Point Books|isbn=978-0-7565-0590-5|location=Minneapolis, Minn.|language=English|oclc=54027960}}</ref><ref name=instar>{{cite journal|last=Valerio |first=C.E. |year=1977 |title=Population structure in the spider ''Achaearranea Tepidariorum'' (Aranae, Theridiidae) |journal=Journal of Arachnology |volume=3 |pages=185–190 |url=http://fms.holycross.edu/JoA_free/JoA_v3_n3/JoA_v3_p185.pdf |archive-url=https://web.archive.org/web/20110719210153/http://fms.holycross.edu/JoA_free/JoA_v3_n3/JoA_v3_p185.pdf |archive-date=July 19, 2011 |access-date=2009-07-18 |url-status=bot: unknown }}</ref>

==Terrestrial==
{{Main|Terrestrial locomotion}}
{{See also|Comparative foot morphology}}
[[File:Alticus arnoldorum hopping - pone.0011197.s007.ogv|thumb|[[Pacific leaping blenny]] ''Alticus arnoldorum'' hopping]]
[[File:Alticus arnoldorum climbing up a vertical piece of Plexiglas - pone.0011197.s009.ogv|thumb|Pacific leaping blenny climbing up a vertical piece of Plexiglas]]
Forms of locomotion on land include walking, running, hopping or [[jumping]], dragging and crawling or slithering. Here friction and buoyancy are no longer an issue, but a strong [[skeletal]] and [[muscular]] framework are required in most terrestrial animals for structural support. Each step also requires much energy to overcome [[inertia]], and animals can store [[elastic potential energy]] in their [[tendon]]s to help overcome this. [[Equilibrioception|Balance]] is also required for movement on land. Human [[infant]]s learn to [[Crawling (human)|crawl]] first before they are able to stand on two feet, which requires good coordination as well as physical development. Humans are [[bipedal]] animals, standing on two feet and keeping one on the ground at all times while [[walking]]. When [[running]], only one [[foot]] is on the ground at any one time at most, and both leave the ground briefly. At higher speeds [[momentum]] helps keep the body upright, so more energy can be used in movement.

===Jumping===
{{main|Jumping}}

[[File:Eastern gray squirrel (Sciurus carolinensis) bounding across a lawn in Central Park 2018.jpeg|thumb|center|270px|Gray squirrel (''Sciurus carolinensis'') in mid-leap]]

Jumping (saltation) can be distinguished from running, galloping, and other gaits where the entire body is temporarily airborne by the relatively long duration of the aerial phase and high angle of initial launch. Many terrestrial animals use jumping (including hopping or leaping) to escape predators or catch prey—however, relatively few animals use this as a primary mode of locomotion. Those that do include the [[kangaroo]] and other macropods, [[rabbit]], [[hare]], [[jerboa]], [[hopping mouse]], and [[kangaroo rat]]. Kangaroo rats often leap 2&nbsp;m<ref name="BLM_CA">{{cite web | title=Merriam's Kangaroo Rat ''Dipodomys merriami'' | work=U. S. Bureau of Land Management web site | publisher=[[Bureau of Land Management]] | url=http://www.blm.gov/ca/forms/wildlife/details.php?metode=serial_number&search=2744&detaillabelc=Merriam | access-date=2014-03-26}}</ref> and reportedly up to 2.75&nbsp;m<ref name="Desert_Museum">{{cite web | last=Merlin | first=P. | title=Heteromyidae: Kangaroo Rats & Pocket Mice | work=Arizona-Sonora Desert Museum web site | publisher=[[Arizona-Sonora Desert Museum]] | date=2014 | url=http://www.desertmuseum.org/books/nhsd_heteromyidae.php | access-date=2014-03-26}}</ref> at speeds up to almost {{convert|3|m/s|mph|abbr=on}}.<ref name="PBS_Guide">{{cite web | title=Animal Guide: Giant Kangaroo Rat | work=Nature on PBS web site | date=2014 | publisher=[[Public Broadcasting System]] | url=https://www.pbs.org/wnet/nature/interactives-extras/animal-guides/animal-guide-giant-kangaroo-rat/2196/ | access-date=2014-03-26 | archive-date=2014-03-26 | archive-url=https://web.archive.org/web/20140326031613/http://www.pbs.org/wnet/nature/interactives-extras/animal-guides/animal-guide-giant-kangaroo-rat/2196/ | url-status=dead }}</ref> They can quickly change their direction between jumps.<ref name="PBS_Guide"/> The rapid locomotion of the banner-tailed kangaroo rat may minimize energy cost and predation risk.<ref name=Schroder1979/> Its use of a "move-freeze" mode may also make it less conspicuous to nocturnal predators.<ref name=Schroder1979>{{cite journal | last=Schroder | first=G.D.| title=Foraging behavior and home range utilization of the Bannertail Kangaroo Rat | journal=[[Ecology (journal)|Ecology]] | volume=60 | issue=4 | pages=657–665 | date=August 1979 | jstor=1936601 | doi=10.2307/1936601}}</ref> Frogs are, relative to their size, the best jumpers of all vertebrates.<ref>{{cite web |url=http://scienceray.com/biology/zoology/top-10-best-jumper-animals/ |title=Top 10 best jumper animals |publisher=Scienceray |access-date=2012-06-11 |archive-url=https://web.archive.org/web/20090907014750/http://scienceray.com/biology/zoology/top-10-best-jumper-animals/ |archive-date=2009-09-07 |url-status=dead}}</ref> The Australian rocket frog, ''[[Litoria nasuta]]'', can leap over {{convert|2|m}}, more than fifty times its body length.<ref>{{cite journal |author1=James, R. S. |author2=Wilson, R. S. |year=2008 |title=Explosive jumping: extreme morphological and physiological specializations of Australian rocket frogs (''Litoria nasuta'') |journal=Physiological and Biochemical Zoology |volume=81 |issue=2 |pages=176–185 |pmid=18190283 |doi=10.1086/525290 |s2cid=12643425 |url=https://espace.library.uq.edu.au/view/UQ:175725/UQ175725_OA.pdf }}</ref>

{{anchor|Peristalsis}}
[[File:Leech looping locomotion.jpg|thumb|upright|[[Leech]] moving by looping using its front and back suckers]]

===Peristalsis and looping===
Other animals move in terrestrial habitats without the aid of legs. [[Earthworm]]s crawl by a [[peristalsis]], the same rhythmic contractions that propel food through the digestive tract.<ref name=Quillan2000>{{cite journal |date=2000 |journal=Journal of Experimental Biology |volume=203 |issue=Pt 18 |pages=2757–2770 |author=Quillan, K.J. |title=Ontogenetic scaling of burrowing forces in the earthworm Lumbricus terrestris |doi=10.1242/jeb.203.18.2757 |url=http://jeb.biologists.org/content/203/18/2757.full.pdf+html |pmid=10952876|bibcode=2000JExpB.203.2757Q |url-access=subscription }}</ref>

[[File:20100214 Leech climbing door at Lake Leake, Tasmania.ogv|thumb|Leech moving on a flat surface]]

[[Leech]]es and [[geometer moth]] caterpillars move by looping or inching (measuring off a length with each movement), using their paired circular and longitudinal muscles (as for peristalsis) along with the ability to attach to a surface at both anterior and posterior ends. One end is attached, often the thicker end, and the other end, often thinner, is projected forward peristaltically until it touches down, as far as it can reach; then the first end is released, pulled forward, and reattached; and the cycle repeats. In the case of leeches, attachment is by a sucker at each end of the body.<ref name="Brusca 2016">{{cite book | last=Brusca | first=Richard | title=Hirudinoidea: Leeches and Their Relatives | work=Invertebrates | publisher=Sinauer Associates | year=2016 | isbn=978-1-60535-375-3 | pages=591–597}}</ref>

===Sliding===
Due to its low coefficient of friction, ice provides the opportunity for other modes of locomotion.  Penguins either waddle on their feet or slide on their bellies across the snow, a movement called ''tobogganing'', which conserves energy while moving quickly. Some pinnipeds perform a similar behaviour called ''sledding''.

===Climbing===
Some animals are specialized for moving on non-horizontal surfaces. One common habitat for such [[arboreal locomotion|climbing animals is in trees]]; for example, the [[gibbon]] is specialized for [[arboreal]] movement, travelling rapidly by [[brachiation]] (see [[#Climbing|below]]).

Others living on rock faces such as in [[mountain]]s move on steep or even near-vertical surfaces by careful balancing and leaping. Perhaps the most exceptional are the various types of mountain-dwelling [[Goat antelope|caprids]] (e.g., [[Barbary sheep]], [[yak]], [[ibex]], [[rocky mountain goat]], etc.), whose adaptations can include a soft rubbery pad between their hooves for grip, hooves with sharp keratin rims for lodging in small footholds, and prominent dew claws. Another case is the [[snow leopard]], which being a predator of such caprids also has spectacular balance and leaping abilities, such as ability to leap up to 17{{Spaces|1}}m (50{{Spaces|1}}ft).

Some light animals are able to climb up smooth sheer surfaces or hang upside down by [[adhesion]] using [[sucker (zoology)|suckers]]. Many insects can do this, though much larger animals such as [[gecko]]s can also perform similar feats.

===Walking and running===
Species have different numbers of legs resulting in large differences in locomotion.

<!--Monopedalism means jumping using one hard foot-->
Modern birds, though classified as [[tetrapod]]s, usually have only two functional legs, which some (e.g., ostrich, emu, kiwi) use as their primary, [[Bipedalism|Bipedal]], mode of locomotion.  A few modern mammalian species are habitual bipeds, i.e., whose normal method of locomotion is two-legged. These include the [[Macropodidae|macropods]], [[Dipodomyinae|kangaroo rats and mice]], [[springhare]],<ref>{{cite journal|author1=Heglund, N.C. | author2=Cavagna, G.A. | author3=Taylor, C.R. | year=1982 | title=Energetics and mechanics of terrestrial locomotion. III. Energy changes of the centre of mass as a function of speed and body size in birds and mammals | journal=Journal of Experimental Biology | volume=97 | pages=41–56 | doi=10.1242/jeb.97.1.1 | pmid=7086349 }}</ref> [[hopping mice]], [[pangolin]]s and [[hominina]]n apes. Bipedalism is rarely found outside [[terrestrial animal]]s—though at least two types of [[octopus]] walk bipedally on the sea floor using two of their arms, so they can use the remaining arms to camouflage themselves as a mat of algae or floating coconut.<ref name="pmid15790846">{{cite journal |vauthors=Huffard CL, Boneka F, Full RJ |title=Underwater bipedal locomotion by octopuses in disguise |journal=Science |volume=307 |issue=5717 |page=1927 |year=2005 |pmid=15790846 |doi=10.1126/science.1109616|s2cid=21030132 }}</ref>

There are no three-legged animals—though some macropods, such as kangaroos, that alternate between resting their weight on their muscular tails and their two hind legs could be looked at as an example of [[Tripedalism|tripedal]] locomotion in animals.

[[File:Muz PGI 1728-II-16 animated v20150114.svg|thumb|Animation of a [[Devonian]] tetrapod]]

Many familiar animals are [[Quadrupedalism|quadrupedal]], walking or running on four legs. A few birds use quadrupedal movement in some circumstances. For example, the [[shoebill]] sometimes uses its wings to right itself after lunging at prey.<ref>{{cite web |last=Naish |first=Darren |url=http://scienceblogs.com/tetrapodzoology/2008/12/balaeniceps_rex.php#more |title=B. rex! – Tetrapod Zoology |publisher=Scienceblogs.com |date=2008-12-03 |access-date=2014-06-10}}</ref> The newly hatched [[hoatzin]] bird has claws on its thumb and first finger enabling it to dexterously climb tree branches until its wings are strong enough for sustained flight.<ref>{{cite journal |doi=10.1111/j.1096-3642.1891.tb00045.x |last=Parker |first= W. K. |year=1891 |url=https://www.biodiversitylibrary.org/page/31083330 |title=On the morphology of a reptilian bird, ''Opisthocomus hoazin'' |journal=Transactions of the Zoological Society of London |volume=13 |pages=43–89 |issue=2}}</ref> These claws are gone by the time the bird reaches adulthood.

A relatively few animals use five limbs for locomotion. [[Prehensile]] quadrupeds may use their tail to assist in locomotion and when grazing, the kangaroos and other macropods use their tail to propel themselves forward with the four legs used to maintain balance.

Insects generally walk with six legs—though some insects such as [[Nymphalidae|nymphalid butterflies]]<ref>{{cite web |title=Butterflies in the Nymphalidae family |url=http://www.bumblebee.org/invertebrates/Lepidoptera1.htm |access-date=4 October 2016}}</ref> do not use the front legs for walking.

[[Arachnid]]s have eight legs. Most arachnids lack [[extension (kinesiology)|extensor]] muscles in the [[distal]] joints of their appendages. Spiders and [[whipscorpion]]s extend their limbs hydraulically using the pressure of their [[hemolymph]].<ref name=Sensenig2003>{{Cite journal| doi=10.1242/jeb.00182| pmid=12517993| issn=1477-9145| volume=206| issue=4| pages=771–784| last=Sensenig| first=Andrew T| author2=Jeffrey W Shultz| title=Mechanics of Cuticular Elastic Energy Storage in Leg Joints Lacking Extensor Muscles in Arachnids| journal=[[Journal of Experimental Biology]]| date=2003-02-15| s2cid=40503319| doi-access=| bibcode=2003JExpB.206..771S}}</ref> [[Solifuge]]s and some [[harvestmen]] extend their knees by the use of highly elastic thickenings in the joint cuticle.<ref name=Sensenig2003/> [[Scorpion]]s, [[pseudoscorpion]]s and some harvestmen have evolved muscles that extend two leg joints (the femur-patella and patella-tibia joints) at once.<ref name=Shultz2005>{{Cite journal| doi=10.1002/jmor.1052100103| pmid=29865543| issn=1097-4687| volume=210| issue=1| pages=13–31| last=Shultz| first=Jeffrey W| title=Evolution of locomotion in arachnida: The hydraulic pressure pump of the giant whipscorpion, Mastigoproctus Giganteus (Uropygi)| journal=[[Journal of Morphology]]| date=2005-02-06 | s2cid=46935000}}</ref><ref name=Shultz1992>{{Cite journal| issn=1477-9145| volume=162| issue=1| pages=313–329| last=Shultz| first=Jeffrey W| title=Muscle Firing Patterns in Two Arachnids Using Different Methods of Propulsive Leg Extension| journal=Journal of Experimental Biology| access-date=2012-05-19| date=1992-01-01| doi=10.1242/jeb.162.1.313| url=http://jeb.biologists.org/content/162/1/313| doi-access=free| bibcode=1992JExpB.162..313S}}</ref>

The scorpion ''[[Hadrurus arizonensis]]'' walks by using two groups of legs (left 1, right 2, Left 3, Right 4 and Right 1, Left 2, Right 3, Left 4) in a reciprocating fashion. This alternating tetrapod coordination is used over all walking speeds.<ref>{{cite journal|author=Bowerman, R.F.|journal=Journal of Comparative Physiology|year=1975|volume=100|issue=3|pages=183–196|title=The control of walking in the scorpion|doi=10.1007/bf00614529|s2cid=26035077}}</ref>

Centipedes and millipedes have many sets of legs that move in [[metachronal rhythm]]. Some echinoderms locomote using the many [[tube feet]] on the underside of their arms.  Although the tube feet resemble suction cups in appearance, the gripping action is a function of adhesive chemicals rather than suction.<ref>{{cite journal|author=Hennebert, E. |author2=Santos, R. |author3=Flammang, P. |name-list-style=amp |year= 2012|title=Echinoderms don't suck: evidence against the involvement of suction in tube foot attachment|journal=Zoosymposia|volume=1|pages=25–32|url=http://www.mapress.com/zoosymposia/content/2012/v7/f/v007p025-032f.pdf |issn=1178-9913|doi=10.11646/zoosymposia.7.1.3 }}</ref>  Other chemicals and relaxation of the ampullae allow for release from the substrate. The tube feet latch on to surfaces and move in a wave, with one arm section attaching to the surface as another releases.<ref name="Dorit">{{cite book |title=Zoology |url=https://archive.org/details/zoology0000dori |url-access=registration |last=Dorit |first= R. L. |author2=Walker, W. F. |author3=Barnes, R. D.  |year=1991 |publisher=Saunders College Publishing |isbn=978-0-03-030504-7 |page=[https://archive.org/details/zoology0000dori/page/782 782] }}</ref><ref>{{cite journal|doi=10.1007/BF00210108 |title=Specializations for excitation-contraction coupling in the podial retractor cells of the starfish ''Stylasterias forreri'' |year=1981 |last1=Cavey |first1= Michael J. |last2=Wood |first2=Richard L. |journal=Cell and Tissue Research |volume=218 |issue=3 |pages=475–485|pmid=7196288 |s2cid=21844282 }}</ref> Some multi-armed, fast-moving starfish such as the [[sunflower seastar]] (''Pycnopodia helianthoides'') pull themselves along with some of their arms while letting others trail behind. Other starfish turn up the tips of their arms while moving, which exposes the sensory tube feet and eyespot to external stimuli.<ref>{{cite web | url=http://www.asnailsodyssey.com/LEARNABOUT/SEASTAR/seasTube.php | title=Sea Star: Tube Feet & Locomotion | publisher=A Snail's Odyssey  | access-date=| author= | archive-url=https://web.archive.org/web/20131021181550/http://www.asnailsodyssey.com/LEARNABOUT/SEASTAR/seasTube.php | archive-date=2013-10-21 |url-status=dead}}</ref>  Most starfish cannot move quickly, a typical speed being that of the [[leather star]] (''Dermasterias imbricata''), which can manage just {{convert|15|cm|0|abbr=on}} in a minute.<ref>{{cite web |url= http://www.seastarsofthepacificnorthwest.info/species/leather_star.html |title=Leather star - ''Dermasterias imbricata'' |publisher=Sea Stars of the Pacific Northwest |access-date=2012-09-27 |archive-url= https://web.archive.org/web/20120909031834/http://www.seastarsofthepacificnorthwest.info/species/leather_star.html |archive-date=2012-09-09 |url-status=dead}}</ref> Some burrowing species from the genera ''[[Astropecten]]'' and ''[[Luidia]]'' have points rather than suckers on their long tube feet and are capable of much more rapid motion, "gliding" across the ocean floor. The sand star (''[[Luidia foliolata]]'') can travel at a speed of {{convert|2.8|m|abbr=on}} per minute.<ref>{{cite web |url=http://www.seastarsofthepacificnorthwest.info/species/sand_star.html |author=McDaniel, Daniel |title=Sand star - ''Luidia foliolata'' |publisher=Sea Stars of the Pacific Northwest |access-date=2012-09-26 |archive-url=https://web.archive.org/web/20120909031724/http://www.seastarsofthepacificnorthwest.info/species/sand_star.html |archive-date=2012-09-09 |url-status=dead}}</ref>  Sunflower starfish are quick, efficient hunters, moving at a speed of {{convert|1|m/min|ft/min|abbr=on}} using 15,000 tube feet.<ref name="noaa">{{cite web|url=http://www.nmfs.noaa.gov/speciesid/fish_page/fish6a.html|title=Sunflower sea star|publisher=National Marine Fisheries Service|access-date=December 27, 2014}}</ref>

Many animals temporarily change the number of legs they use for locomotion in different circumstances. For example, many quadrupedal animals switch to bipedalism to reach low-level browse on trees. The genus of ''[[Basiliscus (genus)|Basiliscus]]'' are arboreal lizards that usually use quadrupedalism in the trees.  When frightened, they can drop to water below and run across the surface on their hind limbs at about 1.5&nbsp;m/s for a distance of approximately {{convert|4.5|m||abbr=on}} before they sink to all fours and swim.  They can also sustain themselves on all fours while "water-walking" to increase the distance travelled above the surface by about 1.3 {{Spaces|1}}m.<ref>{{cite web |url=http://news.nationalgeographic.com/news/2004/11/1116_041116_jesus_lizard.html|archive-url=https://web.archive.org/web/20041119005948/http://news.nationalgeographic.com/news/2004/11/1116_041116_jesus_lizard.html|url-status=dead|archive-date=November 19, 2004|title=How "Jesus Lizards" walk on water |date=16 November 2004 |publisher=National Geographic |access-date=December 22, 2014}}</ref>  When cockroaches run rapidly, they rear up on their two hind legs like bipedal humans; this allows them to run at speeds up to 50 body lengths per second, equivalent to a "couple hundred miles per hour, if you scale up to the size of humans."<ref>{{cite web|author=Sanders, R.|year =2012|title=Stealth behavior allows cockroaches to seemingly vanish|url=http://newscenter.berkeley.edu/2012/06/06/stealth-behavior-allows-cockroaches-to-seemingly-vanish/|publisher=UC Berkeley News Center|access-date=December 22, 2014}}</ref> When grazing, kangaroos use a form of pentapedalism (four legs plus the tail) but switch to hopping (bipedalism) when they wish to move at a greater speed.

<gallery mode="nolines" widths="200px">
File:Ostrich running.ogv|Bipedal ostrich
File:2013-05-09 15-20-00-Extatosoma-tiaratum.ogv|Hexapedal stick-insect
File:Evarcha arcuata (female), Wollenberg, Hesse, Germany - 20110429.ogv|Octopedal locomotion by a spider
File:Red millipede crawling on a wall.webm|Multi-legged millipede
</gallery>

===Powered cartwheeling===
The Moroccan flic-flac spider (''[[Cebrennus rechenbergi]]'') uses a series of rapid, acrobatic [[flic-flac]] movements of its legs similar to those used by gymnasts, to actively propel itself off the ground, allowing it to move both down and uphill, even at a 40 percent incline.<ref name="king">{{cite book|author=King, R.S.|year=2013|title =BiLBIQ: A Biologically Inspired Robot with Walking and Rolling Locomotion|volume=2|publisher=Springer, Verlag, Berlin, Heidelberg|isbn= 978-3-642-34681-1|doi=10.1007/978-3-642-34682-8|series=Biosystems & Biorobotics|url= https://cds.cern.ch/record/1501104}}</ref> This behaviour is different than other huntsman spiders, such as ''[[Carparachne aureoflava]]'' from the [[Namib Desert]], which uses passive [[cartwheeling]] as a form of locomotion.<ref name=senck>{{cite news|author1=Bröhl, I.  |author2= Jördens, J.|title=The Moroccan flic-flac spider: A gymnast among the arachnids|url= http://www.senckenberg.de/root/index.php?page_id=5210&year=2014&kid=2&id=3095 |access-date=23 May 2015|agency=Senckenberg Gesellschaft für Naturforschung|date=April 28, 2014}}</ref> The flic-flac spider can reach speeds of up to 2&nbsp;m/s using forward or back flips to evade threats.<ref name= scin>{{cite news|author=Prostak, S.|title=Cebrennus rechenbergi: Cartwheeling spider discovered in Morocco|url=http://www.sci-news.com/biology/science-cebrennus-rechenbergi-spider-morocco-01903.html|access-date=October 20, 2016|agency=Sci-News.com|date=May 6, 2014}}</ref><ref name=nyt>{{cite news|author=Bhanoo, S.|title=A desert spider with astonishing moves|newspaper=The New York Times |url= https://www.nytimes.com/2014/05/06/science/a-desert-spider-with-astonishing-moves.html?_r=0 |access-date=October 20, 2016|agency=The New York Times|date=May 4, 2014}}</ref>

==Subterranean==
Some animals move through solids such as soil by burrowing using [[peristalsis]], as in [[earthworms]],<ref name=Quillin>{{cite journal |author=Quillin KJ |title=Ontogenetic scaling of hydrostatic skeletons: geometric, static stress and dynamic stress scaling of the earthworm lumbricus terrestris |journal=The Journal of Experimental Biology |volume=201 |issue=12 |pages=1871–83 | date=May 1998 |doi=10.1242/jeb.201.12.1871 |pmid=9600869 |url=http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=9600869|doi-access=free |bibcode=1998JExpB.201.1871Q }}</ref> or other methods. In loose solids such as sand some animals, such as the [[golden mole]], [[marsupial mole]], and the [[pink fairy armadillo]], are able to move more rapidly, "swimming" through the loose substrate. Burrowing animals include [[mole (animal)|moles]], [[ground squirrels]], [[naked mole-rat]]s, [[tilefish]], and [[mole cricket]]s.

==Arboreal locomotion==
{{main|arboreal locomotion}}
[[File:Gibbon Hoolock de l'ouest.JPG|thumb|250px|right|A brachiating gibbon]]
Arboreal locomotion is the locomotion of animals in trees.  Some animals may only scale trees occasionally, while others are exclusively arboreal.  These habitats pose numerous mechanical challenges to animals moving through them, leading to a variety of anatomical, behavioural and ecological consequences as well as variations throughout different species.<ref name=Cartmill>{{cite book|author=Cartmill, M.|year=1985|chapter=Climbing|title=Functional Vertebrate Morphology|editor1=M. Hildebrand |editor2=D.M. Bramble |editor3=K.F. Liem |editor4=D.B. Wake |pages=73–88|publisher=Belknap Press, Cambridge}}</ref>  Furthermore, many of these same principles may be applied to climbing without trees, such as on rock piles or mountains.  The earliest known [[tetrapod]] with specializations that adapted it for climbing trees was ''[[Suminia]]'', a [[synapsid]] of the late [[Permian]], about 260 million years ago.<ref>{{cite journal|author=Fröbisch J. |author2=Reisz, R.R. |name-list-style=amp |year=2009|title=The Late Permian herbivore ''Suminia'' and the early evolution of arboreality in terrestrial vertebrate ecosystems |journal=Proceedings of the Royal Society B: Biological Sciences |doi=10.1098/rspb.2009.0911 |volume=276 |issue=1673 |pages=3611–3618 |pmid=19640883 |pmc=2817304|author2-link=Robert R. Reisz }}</ref> Some invertebrate animals are exclusively arboreal in habitat, for example, the [[tree snail]].

[[Brachiation]] (from ''brachium'', Latin for "arm") is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms. During brachiation, the body is alternately supported under each forelimb. This is the primary means of locomotion for the small [[gibbon]]s and [[siamang]]s of southeast Asia. Some New World monkeys such as spider monkeys and muriquis are "semibrachiators" and move through the trees with a combination of leaping and brachiation. Some New World species also practice [[suspensory behavior]]s by using their [[prehensile tail]], which acts as a fifth grasping hand.<ref name="Jurmain_etal2008">{{Cite book | first1=Robert | last1=Jurmain | first2=Lynn | last2=Kilgore | first3=Wenda | last3=Trevathan | title=Essentials of Physical Anthropology | edition=7 | publisher=Cengage Learning | year=2008 | page=109 | isbn=9780495509394}}</ref>

Pandas are known to swig their heads laterally as they ascend vertical surfaces astonishingly utilizing their head as a propulsive limb in an anatomical way that was thought to only be practiced by certain species of birds.

== Energetics ==
Animal locomotion requires [[energy]] to overcome various forces including [[friction]], [[drag (physics)|drag]], [[inertia]] and [[gravity]], although the influence of these depends on the circumstances. In [[Terrestrial planet|terrestrial]] environments, gravity must be overcome whereas the drag of air has little influence. In aqueous environments, friction (or drag) becomes the major energetic challenge with gravity being less of an influence. Remaining in the aqueous environment, animals with natural [[buoyancy]] expend little energy to maintain a vertical position in a water column. Others naturally sink, and must spend energy to remain afloat. Drag is also an energetic influence in [[flight]], and the [[aerodynamic]]ally efficient body shapes of flying [[bird]]s indicate how they have evolved to cope with this.  Limbless organisms moving on land must energetically overcome surface friction, however, they do not usually need to expend significant energy to counteract gravity.

[[Newton's laws of motion|Newton's third law of motion]] is widely used in the study of animal locomotion: if at rest, to move forwards an animal must push backwards against something.  Terrestrial animals must push the solid ground, swimming and flying animals must push against a [[fluid]] (either [[water]] or [[air]]).<ref name="Bie">{{cite book|last1=Biewener|first1 = A. A.|date =  2003|title= Animal Locomotion|publisher= Oxford University Press|isbn = 978-0198500223}}</ref> The effect of forces during locomotion on the design of the skeletal system is also important, as is the interaction between locomotion and muscle physiology, in determining how the structures and effectors of locomotion enable or limit animal movement.  The [[Bioenergetics#Overview|energetics]] of locomotion involves the energy expenditure by animals in moving. Energy consumed in locomotion is not available for other efforts, so animals typically have evolved to use the minimum energy possible during movement.<ref name="Bie"/>  However, in the case of certain behaviors, such as locomotion to escape a predator, performance (such as speed or maneuverability) is more crucial, and such movements may be energetically expensive.  Furthermore, animals may use energetically expensive methods of locomotion when environmental conditions (such as being within a burrow) preclude other modes.

The most common metric of energy use during locomotion is the net (also termed "incremental") cost of transport, defined as the amount of energy (e.g., [[Joules]]) needed above baseline metabolic rate to move a given distance. For aerobic locomotion, most animals have a nearly constant cost of transport—moving a given distance requires the same caloric expenditure, regardless of speed. This constancy is usually accomplished by changes in [[gait]]. The net cost of transport of swimming is lowest, followed by flight, with terrestrial limbed locomotion being the most expensive per unit distance.<ref name="Campbell">{{cite book | last=Campbell | first=Neil A. |author2=Reece, Jane B. | title=Biology, 7th Edition | publisher=Pearson - Benjamin Cummings | year=2005 | location=San Francisco | pages=522–523  | isbn=978-0-8053-7171-0}}</ref> However, because of the speeds involved, flight requires the most energy per unit time. This does not mean that an animal that normally moves by running would be a more efficient swimmer; however, these comparisons assume an animal is specialized for that form of motion. Another consideration here is [[body mass]]&mdash;heavier animals, though using more total energy, require less energy ''per unit mass'' to move. [[Physiology|Physiologists]] generally measure energy use by the amount of [[oxygen]] consumed, or the amount of [[carbon dioxide]] produced, in an animal's [[respiration (physiology)|respiration]].<ref name="Campbell" /> In terrestrial animals, the cost of transport is typically measured while they walk or run on a motorized treadmill, either wearing a mask to capture gas exchange or with the entire treadmill enclosed in a metabolic chamber. For small [[rodents]], such as [[Peromyscus|deer mice]], the cost of transport has also been measured during voluntary wheel running.<ref>{{cite journal|author=Chappell, M.A. |author2=Garland, T. |author3=Rezende, E.L. |author4=Gomes, F.R. |name-list-style=amp |year=2004|title=Voluntary running in deer mice: Speed, distance, energy costs and temperature effects|journal=Journal of Experimental Biology|volume=207|issue=22 |pages=3839–3854|doi=10.1242/jeb.01213 |pmid=15472015|doi-access=free |bibcode=2004JExpB.207.3839C }}</ref>

Energetics is important for explaining the evolution of foraging economic decisions in organisms; for example, a study of the African honey bee, [[African honey bee|''A. m. scutellata'']], has shown that honey bees may trade the high [[sucrose]] content of viscous [[nectar]] off for the energetic benefits of warmer, less concentrated nectar, which also reduces their consumption and flight time.<ref name="Nicolson et al, 2013">{{cite journal|author=Nicolson, S. |author2=de Veer, L. |author3=Kohler. A. |author4=Pirk, C.W.W. |name-list-style=amp |title=Honeybees prefer warmer nectar and less viscous nectar, regardless of sugar concentration|journal=Proc. R. Soc. B|volume=280 |issue=1767 |year=2013|pages=1–8 |doi=10.1098/rspb.2013.1597|pmid=23902913 |pmc=3735266 }}</ref>

==Passive locomotion==
Passive locomotion in animals is a type of mobility in which the animal depends on their environment for transportation; such animals are vagile but not [[Motility|motile]].<ref name=EB />

===Hydrozoans===
[[File:Physalia physalis1.jpg|thumb|upright|''Physalia physalis'']]
The [[Portuguese man o' war]] (''Physalia physalis'') lives at the surface of the ocean. The gas-filled bladder, or pneumatophore (sometimes called a "sail"), remains at the surface, while the remainder is submerged. Because the Portuguese man o' war has no means of propulsion, it is moved by a combination of winds, currents, and tides.   The sail is equipped with a siphon. In the event of a surface attack, the sail can be deflated, allowing the organism to briefly submerge.<ref>{{cite web |url=http://animals.nationalgeographic.com/animals/printable/portuguese-man-of-war.html |archive-url=https://web.archive.org/web/20071110032730/http://animals.nationalgeographic.com/animals/printable/portuguese-man-of-war.html |url-status=dead |archive-date=November 10, 2007 |title=Portuguese Man-of-War| publisher=National Geographic Society |access-date=December 16, 2014}}</ref>

===Mollusca===
The [[Janthina janthina|violet sea-snail]] (''Janthina janthina'') uses a buoyant foam raft stabilized by [[amphiphilic]] [[mucins]] to float at the sea surface.<ref>{{cite journal |last1=Churchill |first1=Celia K.C. |last2=Ó Foighil |first2=Diarmaid |last3=Strong |first3=Ellen E. |last4=Gittenberger |first4=Adriaan |title=Females floated first in bubble-rafting snails |journal=Current Biology |date=October 2011 |volume=21 |issue=19 |pages=R802–R803 |doi=10.1016/j.cub.2011.08.011 |pmid=21996498 |doi-access=free |bibcode=2011CBio...21.R802C }}</ref><ref>{{cite journal |last1=Rühs |first1=Patrick A. |last2=Bergfreund |first2=Jotam |last3=Bertsch |first3=Pascal |last4=Gstöhl |first4=Stefan J. |last5=Fischer |first5=Peter |title=Complex fluids in animal survival strategies |journal=Soft Matter |date=2021 |volume=17 |issue=11 |pages=3022–3036 |doi=10.1039/D1SM00142F|arxiv=2005.00773 |pmid=33729256 |bibcode=2021SMat...17.3022R |doi-access=free }}</ref>

===Arachnids===
The [[wheel spider]] (''Carparachne aureoflava'') is a [[huntsman spider]] approximately 20&nbsp;mm in size and native to the [[Namib Desert]] of [[Southern Africa]]. The spider escapes parasitic [[Spider wasp|pompilid wasp]]s by flipping onto its side and [[rotating locomotion in living systems|cartwheeling]] down sand [[dune]]s at speeds of up to 44 turns per second.<ref>{{cite web  | title=The Desert is alive  | work=Living Desert Adventures  | year=2008  | url=http://www.living-desert-adventures.com/  | access-date=December 16, 2014  | archive-date=May 16, 2017  | archive-url=https://web.archive.org/web/20170516094516/http://living-desert-adventures.com/  | url-status=dead  }}</ref><ref>{{cite journal | author=Armstrong, S.| title=Fog, wind and heat - life in the Namib desert | issue=1725  | date=14 July 1990 | journal=New Scientist | url=https://www.newscientist.com/article/mg12717253.800--fog-wind-and-heat--life-in-the-namib-desert-researchers-working-in-one-of-the-worlds-most-hostile-environments-are-discovering-how-scores-of-species-manage-to-survive-but-will-the-research-station-itself-survive-as-namibia-gains-its-independence--.html | access-date=2008-10-11 }}</ref>  If the spider is on a sloped dune, its rolling speed may be 1 metre per second.<ref>{{Cite news|editor=Mark Gardiner |title=Feature creature |newspaper=[[Gobabeb|Gobabeb Times]] |page=3 |date=April 2005 |format=PDF |url=http://www.gobabebtrc.org/index.php?option=com_docman&task=doc_download&gid=3&Itemid=107 |url-status=dead|archive-url=https://web.archive.org/web/20120220035431/http://www.gobabebtrc.org/index.php?option=com_docman&task=doc_download&gid=3&Itemid=107 |archive-date=2012-02-20 }}</ref>

A spider (usually limited to individuals of a small species), or spiderling after hatching,<ref>{{cite web|author=Bond, J.E.|url=http://hdl.handle.net/10919/29114|title=Systematics and Evolution of the Californian Trapdoor Spider Genus ''Aptostichus'' Simon (Araneae: Mygalomorphae: Euctenizidae)|publisher=Virginia Polytechnic Institute and State University|year=1999|hdl=10919/29114|access-date=September 26, 2020|archive-url=https://web.archive.org/web/20110608145822/http://scholar.lib.vt.edu/theses/available/etd-092699-200205/unrestricted/etd.pdf|archive-date=June 8, 2011|url-status=live}}</ref> climbs as high as it can, stands on raised legs with its abdomen pointed upwards ("tiptoeing"),<ref name=lab>{{cite journal |last=Weyman |first=G.S. |year=1995 |title=Laboratory studies of the factors stimulating ballooning behavior by Linyphiid spiders (Araneae, Linyphiidae) |journal=The Journal of Arachnology |volume=23 |pages=75–84 |url=http://www.americanarachnology.org/JoA_free/JoA_v23_n2/JoA_v23_p75.pdf |access-date=2009-07-18}}</ref> and then releases several silk threads from its [[Spinneret (spider)|spinnerets]] into the air.  These form a triangle-shaped parachute that carries the spider on updrafts of winds, where even the slightest breeze transports it.  The Earth's [[Static electricity|static electric field]] may also provide lift in windless conditions.<ref>{{cite arXiv |last=Gorham|first=P.|title=Ballooning spiders: The case for electrostatic flight |year=2013 |eprint=1309.4731|class=physics.bio-ph}}</ref>

===Insects===
The [[larva]] of ''[[Cicindela dorsalis]]'', the eastern beach tiger beetle, is notable for its ability to leap into the air, loop its body into a rotating wheel and roll along the sand at a high speed using wind to propel itself. If the wind is strong enough, the larva can cover up to {{convert|60|m}} in this manner. This remarkable ability may have evolved to help the larva escape predators such as the [[Thynnidae|thynnid wasp]] ''[[Methocha]]''.<ref name=WPWL>{{cite journal|title=Wind-powered wheel locomotion, initiated by leaping Somersaults, in larvae of the Southeastern beach tiger beetle (''Cicindela dorsalis media'') | doi=10.1371/journal.pone.0017746 | pmid=21448275 | volume=6 | issue=3 |journal=PLOS ONE |page=e17746|bibcode=2011PLoSO...617746H |year = 2011|last1 = Harvey|first1 = Alan| last2=Zukoff | first2=Sarah | pmc=3063164| doi-access=free }}</ref>

Members of the largest subfamily of cuckoo wasps, [[Chrysidinae]], are generally [[kleptoparasite]]s, laying their eggs in host nests, where their larvae consume the host egg or larva while it is still young.  Chrysidines are distinguished from the members of other subfamilies in that most have flattened or concave lower abdomens and can curl into a defensive ball when attacked by a potential host, a process known as conglobation. Protected by hard chitin in this position, they are expelled from the nest without injury and can search for a less hostile host.

[[Flea]]s can jump vertically up to 18&nbsp;cm and horizontally up to 33&nbsp;cm;<ref name=Crosby>{{cite web|url=http://vetmedicine.about.com/od/parasites/f/FAQ_fleacycle.htm|author=Crosby, J.T.|title=What is the life cycle of the flea|access-date=August 6, 2012|archive-date=September 19, 2005|archive-url=https://web.archive.org/web/20050919195615/http://vetmedicine.about.com/od/parasites/f/FAQ_fleacycle.htm|url-status=dead}}</ref> however, although this form of locomotion is initiated by the flea, it has little control of the jump—they always jump in the same direction, with very little variation in the trajectory between individual jumps.<ref>{{cite web|url=http://www.hfsp.org/frontier-science/frontier-science-matters/insect-jumping-ancient-question|title=Insect jumping: An ancient question|publisher=Human Frontier Science Program|access-date=December 15, 2014|archive-url=https://web.archive.org/web/20141216132547/http://www.hfsp.org/frontier-science/frontier-science-matters/insect-jumping-ancient-question|archive-date=December 16, 2014|url-status=dead}}</ref><ref>{{cite journal|author1=Sutton G.P. |author2=Burrows M. |year=2011|title=The biomechanics of the jump of the flea|journal=Journal of Experimental Biology|volume=214|issue=5 |pages=836–847|doi=10.1242/jeb.052399|pmid=21307071|s2cid=14966793 |doi-access=}}</ref>

===Crustaceans===
Although [[stomatopod]]s typically display the standard locomotion types as seen in [[shrimp|true shrimp]] and [[lobsters]], one species, ''[[Nannosquilla decemspinosa]]'', has been observed flipping itself into a crude wheel. The species lives in shallow, sandy areas.  At low tides, ''N. decemspinosa'' is often stranded by its short rear legs, which are sufficient for locomotion when the body is supported by water, but not on dry land. The mantis shrimp then performs a forward flip in an attempt to roll towards the next tide pool. ''N. decemspinosa'' has been observed to roll repeatedly for {{convert|2|m|ft|abbr=on}}, but they typically travel less than {{convert|1|m|ft|abbr=on}}. Again, the animal initiates the movement but has little control during its locomotion.<ref>{{cite journal |author=Roy L. Caldwell |journal=[[Nature (journal)|Nature]] |volume=282 |pages=71–73 |year=1979 |title=A unique form of locomotion in a stomatopod – backward somersaulting |doi=10.1038/282071a0 |issue=5734|bibcode=1979Natur.282...71C |s2cid=4311328 }}</ref>

===Animal transport===
{{seemain|Phoresis}}
Some animals change location because they are attached to, or reside on, another animal or moving structure.  This is arguably more accurately termed "animal transport".

====Remoras====
[[File:Echeneis naucrates Indonesia.jpg|thumb|right|175px|{{center|Some remoras, such as this ''[[Echeneis naucrates]]'', may attach themselves to scuba divers.}}]]

[[Remora]]s are a family (''Echeneidae'') of [[Actinopterygii|ray-finned fish]].<ref>{{FishBase family | family=Echeneidae | month=April| year=2013}}</ref><ref>{{ITIS | id=168567 | taxon=Echeneidae | access-date=20 March 2006}}</ref> They grow to {{convert|30|–|90|cm|ft|abbr=on}} long, and their distinctive first [[dorsal fin]]s take the form of a modified oval, [[sucker (zoology)|sucker-like organ]] with slat-like structures that open and close to create suction and take a firm hold against the skin of larger marine animals.<ref>{{cite web|url=http://www.nhm.ac.uk/about-us/news/2013/january/sharksucker-fishs-strange-disc-explained118235.html |title=Sharksucker fish's strange disc explained |publisher=Natural History Museum |date=28 January 2013 |access-date=5 February 2013 |url-status=dead|archive-url=https://web.archive.org/web/20130201194123/http://www.nhm.ac.uk/about-us/news/2013/january/sharksucker-fishs-strange-disc-explained118235.html |archive-date=1 February 2013 }}</ref> By sliding backward, the remora can increase the suction, or it can release itself by swimming forward. Remoras sometimes attach to small boats. They swim well on their own, with a sinuous, or curved, motion. When the remora reaches about {{convert|3|cm|abbr=on}}, the disc is fully formed and the remora can then attach to other animals. The remora's lower jaw projects beyond the upper, and the animal lacks a [[swim bladder]]. Some remoras associate primarily with specific host species. They are commonly found attached to sharks, [[manta ray]]s, whales, turtles, and [[dugong]]s. Smaller remoras also fasten onto fish such as tuna and [[swordfish]], and some small remoras travel in the mouths or gills of large manta rays, [[ocean sunfish]], swordfish, and [[sailfish]]. The remora benefits by using the host as transport and protection, and also feeds on materials dropped by the host.

====Angler fish====
In some species of [[anglerfish]], when a male finds a female, he bites into her skin, and releases an [[enzyme]] that digests the skin of his mouth and her body, fusing the pair down to the blood-vessel level. The male becomes dependent on the female host for survival by receiving nutrients via their shared circulatory system, and provides sperm to the female in return. After fusing, males increase in volume and become much larger relative to free-living males of the species. They live and remain reproductively functional as long as the female lives, and can take part in multiple spawnings. This extreme [[sexual dimorphism]] ensures, when the female is ready to spawn, she has a mate immediately available. Multiple males can be incorporated into a single individual female with up to eight males in some species, though some taxa appear to have a one male per female rule.<ref name="doran">{{cite journal | author =Pietsch, T.W. | title=Precocious sexual parasitism in the deep sea ceratioid anglerfish, Cryptopsaras couesi Gill | volume=256 | issue =5512 | doi=10.1038/256038a0 | journal=Nature | pages=38–40| bibcode=1975Natur.256...38P | year =1975 | s2cid=4226567 }}</ref><ref name="gould">{{cite book |last1=Gould |first1=Stephen Jay |title=Hen's Teeth and Horse's Toes |url=https://archive.org/details/hensteethhorsest00goul |url-access=registration |year=1983 |publisher=W. W. Norton & Company |location=New York |isbn=978-0-393-01716-8 |page=[https://archive.org/details/hensteethhorsest00goul/page/30 30]}}</ref>

====Parasites====
Many [[parasites]] are transported by their hosts. For example, endoparasites such as [[Cestoda|tapeworms]] live in the alimentary tracts of other animals, and depend on the host's ability to move to distribute their eggs. Ectoparasites such as [[flea]]s can move around on the body of their host, but are transported much longer distances by the host's locomotion. Some ectoparasites such as [[lice]] can opportunistically hitch a ride on a fly ([[Phoresis (biology)|phoresis]]) and attempt to find a new host.<ref>{{cite book |title=Ecology and Evolution of Transmission in Feather-feeding Lice (Phthiraptera: Ischnocera)|author=University of Utah |url=https://books.google.com/books?id=RUfFjqPoQTEC&pg=PA83 |year=2008 |isbn=978-0-549-46429-7 |pages=83–87}}</ref>

==Changes between media==
Some animals locomote between different media, e.g., from aquatic to aerial.  This often requires different modes of locomotion in the different media and may require a distinct transitional locomotor behaviour.

There are a large number of semi-aquatic animals (animals that spend part of their life cycle in water, or generally have part of their anatomy underwater).  These represent the major taxa of mammals (e.g., beaver, otter, polar bear), birds (e.g., penguins, ducks), reptiles (e.g., anaconda, bog turtle, marine iguana) and amphibians (e.g., salamanders, frogs, newts).

===Fish===
Some fish use multiple modes of locomotion. [[Walking fish]] may swim freely or at other times "walk" along the ocean or river floor, but not on land (e.g., the [[flying gurnard]]—which does not actually fly—and batfishes of the family Ogcocephalidae). [[Amphibious fish]], are fish that are able to leave water for extended periods of time. These fish use a range of terrestrial locomotory modes, such as [[lateral undulation]], [[tripod]]-like walking (using paired [[fin]]s and [[tail]]), and jumping. Many of these locomotory modes incorporate multiple combinations of [[pectoral fin|pectoral]], [[pelvic]] and tail fin movement. Examples include [[eel]]s, [[mudskippers]] and the [[walking catfish]]. [[Flying fish]] can make powerful, self-propelled leaps out of water into air, where their long, wing-like fins enable gliding flight for considerable distances above the water's surface. This uncommon ability is a natural defence mechanism to evade predators. The flights of flying fish are typically around 50&nbsp;m,<ref name="Piper 2007"/> though they can use updrafts at the leading edge of waves to cover distances of up to {{convert|400|m|abbr=on}}.<ref name="Piper 2007"/><ref name="Flying Fish, Exocoetidae"/> They can travel at speeds of more than {{convert|70|km/h|abbr=on}}.<ref name=history/> Maximum altitude is {{convert|6|m|abbr=on}} above the surface of the sea.<ref name=fin>{{cite journal|last=Fish |first=F. |year=1991 |title=On a fin and a prayer |journal=[[Scholars (journal)|Scholars]] |volume=3 |issue=1 |pages=4–7 |url=http://darwin.wcupa.edu/~biology/fish/pubs/pdf/1991SOnafin.pdf |url-status=dead|archive-url=https://web.archive.org/web/20131102103320/http://darwin.wcupa.edu/~biology/fish/pubs/pdf/1991SOnafin.pdf |archive-date=2013-11-02 }}</ref> Some accounts have them landing on ships' decks.<ref name=history/><ref>{{cite book |author=Joseph Banks |url=http://setis.library.usyd.edu.au/ozlit/pdf/p00021.pdf |title=The Endeavour Journal of Sir Joseph Banks 1768–1771 |year=1997 |publisher=[[University of Sydney Library]] |access-date=July 16, 2009}}</ref>

===Marine mammals===
[[File:PacificWhiteSidedDolphine.jpg|thumb|right|250px|Pacific white-sided dolphins porpoising]]
When swimming, several marine mammals such as dolphins, porpoises and pinnipeds, frequently leap above the water surface whilst maintaining horizontal locomotion. This is done for various reasons. When travelling, jumping can save dolphins and porpoises energy as there is less friction while in the air.<ref name=Weihs>{{cite journal|last=Weihs|first=D.|title=Dynamics of Dolphin Porpoising Revisited|journal=Integrative and Comparative Biology|year=2002|volume=42|issue=5|pages=1071–1078|doi=10.1093/icb/42.5.1071|pmid=21680390|doi-access=free}}</ref> This type of travel is known as "porpoising".<ref name=Weihs /> Other reasons for dolphins and porpoises performing porpoising include orientation, social displays, fighting, [[non-verbal communication]], entertainment and attempting to dislodge [[parasite]]s.<ref>{{cite web|author=Binns, C.|publisher=LiveScience|year=2006|url=http://www.livescience.com/678-dolphins-spin.html|title=How dolphins spin, and why|access-date=December 20, 2014}}</ref> In pinnipeds, two types of porpoising have been identified. "High porpoising" is most often near (within 100 m) the shore and is often followed by minor course changes; this may help seals get their bearings on beaching or rafting sites. "Low porpoising" is typically observed relatively far (more than 100 m) from shore and often aborted in favour of anti-predator movements; this may be a way for seals to maximize sub-surface vigilance and thereby reduce their vulnerability to sharks<ref>{{cite web|url=http://www.elasmo-research.org/education/white_shark/seal_antipred.htm|title=Anti-predatory strategies of Cape fur seals at Seal Island|publisher=ReefQuest Centre for Shark Research|access-date=December 20, 2014}}</ref>

Some whales raise their (entire) body vertically out of the water in a behaviour known as "breaching".

===Birds===
Some semi-aquatic birds use terrestrial locomotion, surface swimming, underwater swimming and flying (e.g., ducks, swans). [[Diving birds]] also use diving locomotion (e.g., dippers, auks). Some birds (e.g., [[ratites]]) have lost the primary locomotion of flight.  The largest of these, [[ostrich]]es, when being pursued by a predator, have been known to reach speeds over {{Convert|70|km/h|mph|abbr=on}},<ref name="Davies">{{Cite encyclopedia |last=Davies |first=S.J.J.F.|editor=Hutchins, Michael |encyclopedia=Grzimek's Animal Life Encyclopedia |title= Birds I Tinamous and Ratites to Hoatzins |edition=2 |year=2003 |publisher=Gale Group |volume=8 |location=Farmington Hills, MI|isbn=978-0-7876-5784-0 |pages=99–101}}</ref> and can maintain a steady speed of {{Convert|50|km/h|mph|abbr=on}}, which makes the ostrich the world's fastest two-legged animal:<ref name=DesertUSA>{{cite web| url=http://www.desertusa.com/animals/ostrich.html | title=Ostrich | access-date=17 February 2011 | last=Desert USA | year=1996 | publisher=Digital West Media}}</ref><ref name="Stewart2006">{{cite web| last=Stewart | first=D. | title=A Bird Like No Other  | work=[[National Wildlife]]| publisher=[[National Wildlife Federation]] | date=2006-08-01 | access-date=2014-05-30| url=http://www.nwf.org/News-and-Magazines/National-Wildlife/Birds/Archives/2006/A-Bird-Like-No-Other.aspx| archive-url=https://web.archive.org/web/20120209033650/http://www.nwf.org/News-and-Magazines/National-Wildlife/Birds/Archives/2006/A-Bird-Like-No-Other.aspx| archive-date=2012-02-09}}</ref> Ostriches can also locomote by swimming.<ref>{{cite web| last = Holladay| first = April | title = Ostriches swim! | work = USA Today | date = 23 April 2007 | url = http://usatoday30.usatoday.com/tech/columnist/aprilholladay/2007-04-23-ostriches-swim_N.htm}}</ref> Penguins either waddle on their feet or slide on their bellies across the snow, a movement called ''tobogganing'', which conserves energy while moving quickly. They also jump with both feet together if they want to move more quickly or cross steep or rocky terrain. To get onto land, penguins sometimes propel themselves upwards at a great speed to leap out the water.

==Changes during the life-cycle==
An animal's mode of locomotion may change considerably during its life-cycle. [[Barnacles]] are exclusively marine and tend to live in shallow and tidal waters. They have two [[nekton]]ic (active swimming) larval stages, but as adults, they are [[Sessility (motility)|sessile]] (non-motile) suspension feeders. Frequently, adults are found attached to moving objects such as whales and ships, and are thereby transported (passive locomotion) around the oceans.

==Function==
[[File:American paddlefish filter feeding.webm|thumb|260px|thumbtime=0:20|Paddlefish ram suspension-feeding zooplankton in aquarium]]

Animals locomote for a variety of reasons, such as to find food, a mate, a suitable microhabitat, or to escape predators.

===Food procurement===

Animals use locomotion in a wide variety of ways to procure food. Terrestrial methods include [[Ambush predator|ambush predation]], social predation and [[grazing]]. Aquatic methods include [[Filter feeders|filterfeeding]], grazing, ram feeding, suction feeding, protrusion and pivot feeding. Other methods include [[parasitism]] and [[parasitoid]]ism.

== Quantifying body and limb movement ==
{{main|Study of animal locomotion}}

The [[study of animal locomotion]] is a branch of biology that investigates and quantifies how animals move. It is an application of [[kinematics]], used to understand how the movements of animal limbs relate to the motion of the whole animal, for instance when walking or flying.<ref name=":0">{{Cite journal |last1=Darmohray |first1=Dana M. |last2=Jacobs |first2=Jovin R. |last3=Marques |first3=Hugo G. |last4=Carey |first4=Megan R. |date=2019-04-03 |title=Spatial and Temporal Locomotor Learning in Mouse Cerebellum |journal=Neuron |language=en |volume=102 |issue=1 |pages=217–231.e4 |doi=10.1016/j.neuron.2019.01.038 |issn=0896-6273 |pmid=30795901 |doi-access=free}}</ref><ref name=":1">{{Cite journal |last1=DeAngelis |first1=Brian D. |last2=Zavatone-Veth |first2=Jacob A. |last3=Clark |first3=Damon A |date=2019-06-28 |editor-last=Calabrese |editor-first=Ronald L. |title=The manifold structure of limb coordination in walking Drosophila |journal=eLife |volume=8 |pages=e46409 |doi=10.7554/eLife.46409 |pmid=31250807 |pmc=6598772 |issn=2050-084X |doi-access=free}}</ref><ref name=takeoff-landing-berg>{{cite journal |author1=Berg Angela, M. |author2=Biewener, Andrew A. |title=Wing and body kinematics of takeoff and landing flight in the pigeon (''Columba livia'') |journal=Journal of Experimental Biology |volume=213 |pages=1651–1658 |date= 2010 |issue=10 |doi=10.1242/jeb.038109 |pmid=20435815 |doi-access=free |bibcode=2010JExpB.213.1651B }}</ref>

==Galleries==
{{Gallery
|title=Swimming in major groups of formerly terrestrial animals
|align=left
|width=200
|File:Schwimmender Nutria Walzbach Weingarten 2011.JPG|[[Coypu]] (Rodentia)
|File:Schwimmender Frosch Nahaufnahme.JPG|[[Frog]] (Anura)
|File:Sperm whale pod.jpg|[[Sperm whale]]s (Cetacea)
|File:Pygoscelis papua -Nagasaki Penguin Aquarium -swimming underwater-8a.jpg|[[Gentoo penguin]] (Aves)
|File:Marine Iguana swimming, Fernandina, Punta Espinosa.jpg|[[Marine iguana]] (Reptilia)
}}

{{Gallery
|title=Flight in major groups
|align=left
|width=250
|File:Australian_Emperor_in_flight.jpg|Australian Emperor dragonfly (Insecta)
|File:Magpie_Goose_taking_off.jpg|Magpie goose (Aves)
|File:Big-eared-townsend-fledermaus.jpg|Townsend's big-eared bat (Chiroptera)
}}
{{clear}}

==See also==
* [[Animal migration]]
* [[Animal navigation]]
* [[Bird feet and legs]]
* [[Feather]]
* [[Joint]]
* [[Kinesis (biology)]]
* [[Microswimmer]]
* ''[[Movement of Animals]]'' (book)
* [[Role of skin in locomotion]]
* [[Sessility (motility)|Sessile]]
* [[Taxis]]

==References==
{{reflist|30em}}

==Further reading==
* [[Robert McNeill Alexander|McNeill Alexander, Robert]]. (2003) ''Principles of Animal Locomotion''. Princeton University Press, Princeton, N.J.  {{ISBN|0-691-08678-8}}

== External links ==
{{Commons-inline}}
* [http://www.olfacts.nl/index_bestanden/Page9.html Beetle Orientation] {{Webarchive|url=https://web.archive.org/web/20120310072128/http://www.olfacts.nl/index_bestanden/Page9.html |date=2012-03-10 }}
* [https://web.archive.org/web/20100726231603/http://www.dukenews.duke.edu/2005/12/locomotiontheory.html Unified Physics Theory Explains Animals' Running, Flying And Swimming]

{{fins, limbs and wings}}
{{locomotion}}
{{Musculoskeletal physiology}}

{{Authority control}}

[[Category:Animal locomotion| ]]
[[Category:Ethology]]
[[Category:Zoology]]
[[Category:Animals]]
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