Animal locomotion

{{For|the Eadweard Muybridge study|Animal Locomotion{{!}}Animal Locomotion}}

File:Bioluminescent beetle Elateroidea - animated.gif performing a rectilinear locomotion.]]

In ethology, animal locomotion is any of a variety of methods that animals use to move from one place to another.{{cite web|url=http://www.britannica.com/EBchecked/topic/345861/locomotion|title=Animal locomotion|publisher=Encyclopædia Britannica|access-date=December 16, 2014}} Some modes of locomotion are (initially) self-propelled, e.g., running, swimming, jumping, 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), kiting (spiders), rolling (some beetles and spiders) or riding other animals (phoresis).

Animals move for a variety of reasons, such as to find food, a mate, a suitable microhabitat, or to 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, 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 predators are likely to have energetically costly, but very fast, locomotion.

The anatomical structures that animals use for movement, including cilia, legs, wings, arms, fins, or tails are sometimes referred to as locomotory organs{{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 }} or locomotory structures.{{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}}

Etymology

The term "locomotion" is formed in English from Latin loco "from a place" (ablative of locus "place") + motio "motion, a moving".{{cite web|url=http://www.etymonline.com/index.php?term=locomotion|title=Locomotion|access-date=December 16, 2014|publisher=Online Etymology Dictionary}}

The movement of whole body is called locomotion

Aquatic

=Swimming=

File:Dolphinsurfresize.jpg

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 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 catching prey. A fusiform, torpedo-like body form is seen in many aquatic animals,{{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}}{{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 }} 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 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 mammals 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".{{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}} Some fish propel themselves without a wave motion of the body, as in the slow-moving seahorses and Gymnotus.{{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 }}

Other animals, such as cephalopods, use jet propulsion to travel fast, taking in water then squirting it back out in an explosive burst.{{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}} 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 cetaceans, now very distinct from their terrestrial ancestors.

Dolphins sometimes ride on the bow waves created by boats or surf on naturally breaking waves.{{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 }}

=Benthic=

File:scallop jump.svg 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.{{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 }} Some sea urchins also use their spines for benthic locomotion.{{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}}

Crabs typically walk sideways{{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 }} (a behaviour that gives us the word crabwise). This is because of the articulation of the legs, which makes a sidelong gait more efficient.{{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 }} However, some crabs walk forwards or backwards, including raninids,{{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}} Libinia emarginata{{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 }} and Mictyris platycheles. Some crabs, notably the Portunidae and Matutidae, are also capable of swimming,{{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 }} the Portunidae especially so as their last pair of walking legs are flattened into swimming paddles.{{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}}

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.{{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}}

Aquatic surface

File:Velella Bae an Anaon.jpg moves by sailing.]]

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.{{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}}

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.{{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}} Another form of locomotion (in which the surface layer is broken) is used by the basilisk lizard.{{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}}

Aerial

=Active flight=

File:Gonepteryx rhamni Twisting Wings in Courtship Flight.jpg 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 and fly up towards the female.]]

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 to ascend and remain airborne. One way to achieve this is with wings, which when moved through the air generate an upward 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. Other structural adaptations of flying animals include reduced and redistributed body weight, fusiform shape and powerful flight muscles;{{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 }} there may also be physiological adaptations.{{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 }} Active flight has independently evolved at least four times, in the insects, pterosaurs, birds, and bats. Insects were the first taxon to evolve flight, approximately 400 million years ago (mya),{{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}} followed by pterosaurs approximately 220 mya,{{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}} birds approximately 160 mya,{{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 }} then bats about 60 mya.{{cite web |title=Vertebrate flight: Chiropteran flight |url=http://www.ucmp.berkeley.edu/vertebrates/flight/bats.html |access-date=October 14, 2016}}{{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. Gliding is heavier-than-air flight without the use of thrust; the term "volplaning" also refers to this mode of flight in animals.{{Citation|title=volplane|url=https://www.thefreedictionary.com/volplane|work=The Free Dictionary|access-date=2022-01-06}} 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 ants), reptiles (e.g., banded flying snake), amphibians (e.g., flying frog), mammals (e.g., sugar glider, squirrel glider).

File:Pink-wing flying fish.jpg

Some aquatic animals also regularly use gliding, for example, flying fish, octopus and squid. The flights of flying fish are typically around 50 meters (160 ft),Ross Piper (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press. though they can use updrafts at the leading edge of waves to cover distances of up to {{convert|400|m|abbr=on}}.{{Cite web|date=2010-04-11|title=Flying Fish | 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}} To glide upward out of the water, a flying fish moves its tail up to 70 times per second.{{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 }}

Several oceanic squid, such as the Pacific flying squid, leap out of the water to escape predators, an adaptation similar to that of flying fish.{{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 }} 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.{{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 }} 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}}.{{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}}

=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.{{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}} Soaring birds may alternate glides with periods of soaring in rising air. Five principal types of lift are used:{{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}} thermals, ridge lift, lee waves, convergences and dynamic soaring.

Examples of soaring flight by birds are the use of:

Thermals and convergences by raptors such as vultures
Ridge lift by gulls near cliffs
Wave lift by migrating birds[Report of use of wave lift by birds by Netherlands Institute for Ecology]{{full citation needed|date=June 2023}}
Dynamic effects near the surface of the sea by albatrosses

=Ballooning=

Ballooning is a method of locomotion used by spiders. Certain silk-producing arthropods, mostly small or young spiders, secrete a special light-weight gossamer silk for ballooning, sometimes traveling great distances at high altitude.{{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}}{{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 }}

Terrestrial

File:Alticus arnoldorum hopping - pone.0011197.s007.ogv Alticus arnoldorum hopping]]

File:Alticus arnoldorum climbing up a vertical piece of Plexiglas - pone.0011197.s009.ogv

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 tendons to help overcome this. Balance is also required for movement on land. Human infants learn to 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=

File:Eastern gray squirrel (Sciurus carolinensis) bounding across a lawn in Central Park 2018.jpeg

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 m{{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}} and reportedly up to 2.75 m{{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}} at speeds up to almost {{convert|3|m/s|mph|abbr=on}}.{{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 }} They can quickly change their direction between jumps. The rapid locomotion of the banner-tailed kangaroo rat may minimize energy cost and predation risk. Its use of a "move-freeze" mode may also make it less conspicuous to nocturnal predators.{{cite journal | last=Schroder | first=G.D.| title=Foraging behavior and home range utilization of the Bannertail Kangaroo Rat | journal=Ecology | volume=60 | issue=4 | pages=657–665 | date=August 1979 | jstor=1936601 | doi=10.2307/1936601}} Frogs are, relative to their size, the best jumpers of all vertebrates.{{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}} The Australian rocket frog, Litoria nasuta, can leap over {{convert|2|m}}, more than fifty times its body length.{{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 }}

File:Leech looping locomotion.jpg moving by looping using its front and back suckers]]

=Peristalsis and looping=

Other animals move in terrestrial habitats without the aid of legs. Earthworms crawl by a peristalsis, the same rhythmic contractions that propel food through the digestive tract.{{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 }}

File:20100214 Leech climbing door at Lake Leake, Tasmania.ogv

Leeches 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.{{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}}

=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 climbing animals is in trees; for example, the gibbon is specialized for arboreal movement, travelling rapidly by brachiation (see below).

Others living on rock faces such as in mountains move on steep or even near-vertical surfaces by careful balancing and leaping. Perhaps the most exceptional are the various types of mountain-dwelling 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 suckers. Many insects can do this, though much larger animals such as geckos can also perform similar feats.

=Walking and running=

Species have different numbers of legs resulting in large differences in locomotion.

Modern birds, though classified as tetrapods, usually have only two functional legs, which some (e.g., ostrich, emu, kiwi) use as their primary, 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 macropods, kangaroo rats and mice, springhare,{{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 }} hopping mice, pangolins and homininan apes. Bipedalism is rarely found outside terrestrial animals—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.{{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 }}

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 tripedal locomotion in animals.

File:Muz PGI 1728-II-16 animated v20150114.svg tetrapod]]

Many familiar animals are 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.{{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}} 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.{{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}} 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 nymphalid butterflies{{cite web |title=Butterflies in the Nymphalidae family |url=http://www.bumblebee.org/invertebrates/Lepidoptera1.htm |access-date=4 October 2016}} do not use the front legs for walking.

Arachnids have eight legs. Most arachnids lack extensor muscles in the distal joints of their appendages. Spiders and whipscorpions extend their limbs hydraulically using the pressure of their hemolymph.{{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}} Solifuges and some harvestmen extend their knees by the use of highly elastic thickenings in the joint cuticle. Scorpions, pseudoscorpions and some harvestmen have evolved muscles that extend two leg joints (the femur-patella and patella-tibia joints) at once.{{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}}{{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}}

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.{{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}}

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.{{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 }} 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.{{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] }}{{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 }} 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.{{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}} 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.{{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}} 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.{{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}} Sunflower starfish are quick, efficient hunters, moving at a speed of {{convert|1|m/min|ft/min|abbr=on}} using 15,000 tube feet.{{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}}

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 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 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.{{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}} 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."{{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}} 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.

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

=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.{{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}} 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.{{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}} The flic-flac spider can reach speeds of up to 2 m/s using forward or back flips to evade threats.{{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}}{{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}}

Subterranean

Some animals move through solids such as soil by burrowing using peristalsis, as in earthworms,{{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 }} 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 moles, ground squirrels, naked mole-rats, tilefish, and mole crickets.

Arboreal locomotion

File:Gibbon Hoolock de l'ouest.JPG

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.{{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}} 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.{{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 }} 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 gibbons and siamangs 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 behaviors by using their prehensile tail, which acts as a fifth grasping hand.{{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}}

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, inertia and gravity, although the influence of these depends on the circumstances. In 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 aerodynamically efficient body shapes of flying birds 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 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).{{cite book|last1=Biewener|first1 = A. A.|date = 2003|title= Animal Locomotion|publisher= Oxford University Press|isbn = 978-0198500223}} 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 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. 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.{{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}} 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—heavier animals, though using more total energy, require less energy per unit mass to move. Physiologists generally measure energy use by the amount of oxygen consumed, or the amount of carbon dioxide produced, in an animal's respiration. 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 deer mice, the cost of transport has also been measured during voluntary wheel running.{{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 }}

Energetics is important for explaining the evolution of foraging economic decisions in organisms; for example, a study of the 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.{{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 }}

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 motile.

=Hydrozoans=

File:Physalia physalis1.jpg

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.{{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}}

=Mollusca=

The violet sea-snail (Janthina janthina) uses a buoyant foam raft stabilized by amphiphilic mucins to float at the sea surface.{{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 }}{{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 }}

=Arachnids=

The wheel spider (Carparachne aureoflava) is a huntsman spider approximately 20 mm in size and native to the Namib Desert of Southern Africa. The spider escapes parasitic pompilid wasps by flipping onto its side and cartwheeling down sand dunes at speeds of up to 44 turns per second.{{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 }}{{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 }} If the spider is on a sloped dune, its rolling speed may be 1 metre per second.{{Cite news|editor=Mark Gardiner |title=Feature creature |newspaper=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 }}

A spider (usually limited to individuals of a small species), or spiderling after hatching,{{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}} climbs as high as it can, stands on raised legs with its abdomen pointed upwards ("tiptoeing"),{{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}} and then releases several silk threads from its 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 electric field may also provide lift in windless conditions.{{cite arXiv |last=Gorham|first=P.|title=Ballooning spiders: The case for electrostatic flight |year=2013 |eprint=1309.4731|class=physics.bio-ph}}

=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 thynnid wasp Methocha.{{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 }}

Members of the largest subfamily of cuckoo wasps, Chrysidinae, are generally kleptoparasites, 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.

Fleas can jump vertically up to 18 cm and horizontally up to 33 cm;{{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}} 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.{{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}}{{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=}}

=Crustaceans=

Although stomatopods typically display the standard locomotion types as seen in 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.{{cite journal |author=Roy L. Caldwell |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 }}

=Animal transport=

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, may attach themselves to scuba divers.}}]]

Remoras are a family (Echeneidae) of ray-finned fish.{{FishBase family | family=Echeneidae | month=April| year=2013}}{{ITIS | id=168567 | taxon=Echeneidae | access-date=20 March 2006}} They grow to {{convert|30|–|90|cm|ft|abbr=on}} long, and their distinctive first dorsal fins take the form of a modified oval, 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.{{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 }} 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 rays, whales, turtles, and dugongs. 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.{{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 }}{{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]}}

==Parasites==

Many parasites are transported by their hosts. For example, endoparasites such as 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 fleas 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) and attempt to find a new host.{{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}}

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 fins and tail), and jumping. Many of these locomotory modes incorporate multiple combinations of pectoral, pelvic and tail fin movement. Examples include eels, 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 m, though they can use updrafts at the leading edge of waves to cover distances of up to {{convert|400|m|abbr=on}}. They can travel at speeds of more than {{convert|70|km/h|abbr=on}}. Maximum altitude is {{convert|6|m|abbr=on}} above the surface of the sea.{{cite journal|last=Fish |first=F. |year=1991 |title=On a fin and a prayer |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 }} Some accounts have them landing on ships' decks.{{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}}

=Marine mammals=

File:PacificWhiteSidedDolphine.jpg

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.{{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}} This type of travel is known as "porpoising". Other reasons for dolphins and porpoises performing porpoising include orientation, social displays, fighting, non-verbal communication, entertainment and attempting to dislodge parasites.{{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}} 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{{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}}

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, ostriches, when being pursued by a predator, have been known to reach speeds over {{Convert|70|km/h|mph|abbr=on}},{{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}} 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:{{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}}{{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}} Ostriches can also locomote by swimming.{{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}} 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 nektonic (active swimming) larval stages, but as adults, they are 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

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 predation, social predation and grazing. Aquatic methods include filterfeeding, grazing, ram feeding, suction feeding, protrusion and pivot feeding. Other methods include parasitism and parasitoidism.

Quantifying body and limb movement

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.{{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}}{{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}}{{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 }}

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 whales (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)

}}