![Bioluminescent beetle Elateroidea - animated](https://upload.wikimedia.org/wikipedia/commons/a/a0/Bioluminescent_beetle_Elateroidea_-_animated.gif)
Animal locomotion, in
ethology
Ethology is the scientific study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objectiv ...
, is any of a variety of methods that
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
s use to move from one place to another.
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
Phoresis or phoresy is a non-permanent, commensalistic interaction in which one organism (a phoront or phoretic) attaches itself to another (the host) solely for the purpose of travel. Phoresis has been observed directly in ticks and mites s ...
).
Animals move for a variety of reasons, such as to find
food
Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is inge ...
, a
mate
Mate may refer to:
Science
* Mate, one of a pair of animals involved in:
** Mate choice, intersexual selection
** Mating
* Multi-antimicrobial extrusion protein, or MATE, an efflux transporter family of proteins
Person or title
* Friendship ...
, a suitable
microhabitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
, or to
escape predators. For many animals, the ability to move is essential for survival and, as a result,
natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...
has shaped the locomotion methods and mechanisms used by moving organisms. For example,
migratory animals that travel vast distances (such as the
Arctic tern
The Arctic tern (''Sterna paradisaea'') is a tern in the family Laridae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe (as far south as Brittany), Asia, and North America (as far south a ...
) 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
The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...
,
leg
A leg is a weight-bearing and animal locomotion, locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single ...
s,
wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
s,
arm
In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between the ...
s,
fin
A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...
s, or
tail
The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...
s are sometimes referred to as ''locomotory organs'' or ''locomotory structures''.
Etymology
The term "locomotion" is formed in English from Latin ''loco'' "from a place" (ablative of ''locus'' "place") + ''motio'' "motion, a moving".
Locomotion in different media
Animals move through, or on, four types of environment:
aquatic (in or on water),
terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
(on ground or other surface, including
arboreal
Arboreal locomotion is the Animal locomotion, locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. Th ...
, or tree-dwelling),
fossorial
A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees.
Prehistoric eviden ...
(underground), and
aerial (in the air). Many animals—for example
semi-aquatic
In biology, semiaquatic can refer to various types of animals that spend part of their time in water, or plants that naturally grow partially submerged in water. Examples are given below.
Semiaquatic animals
Semiaquatic animals include:
* Verte ...
animals, and
diving bird
Diving birds are birds which plunge into the water to catch fish or other prey. Such birds may enter the water from flight, such as pelicans, gannets and tropicbirds; or they may dive from the surface of the water, such as the diving ducks, cormora ...
s—regularly move through more than one type of medium. In some cases, the surface they move on facilitates their method of locomotion.
Aquatic
Swimming
![Dolphinsurfresize](https://upload.wikimedia.org/wikipedia/commons/b/b3/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
A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...
-like body form is seen in many aquatic animals,
though the mechanisms they use for locomotion are diverse.
The primary means by which
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
generate
thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...
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
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
(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
Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their reli ...
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".
Some fish propel themselves without a wave motion of the body, as in the slow-moving seahorses and ''
Gymnotus
''Gymnotus'' is a genus of Neotropical freshwater fish in the family Gymnotidae found widely in South America, Central America and southern Mexico (36th parallel south to 18th parallel north). The greatest species richness is found in the Amazon ...
''.
Other animals, such as
cephalopods
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, an ...
, use
jet propulsion
Jet propulsion is the propulsion of an object in one direction, produced by ejecting a jet of fluid in the opposite direction. By Newton's third law, the moving body is propelled in the opposite direction to the jet. Reaction engines operating o ...
to travel fast, taking in water then squirting it back out in an explosive burst.
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
Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...
s, now very distinct from their terrestrial ancestors.
Dolphins sometimes ride on the
bow wave
A bow wave is the wave that forms at the bow of a ship when it moves through the water. As the bow wave spreads out, it defines the outer limits of a ship's wake. A large bow wave slows the ship down, is a risk to smaller boats, and in a harbor ...
s created by boats or surf on naturally breaking waves.
Benthic
Benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
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
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea li ...
primarily use their
tube feet
Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on britt ...
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
Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...
, provides adhesion. Waves of tube feet contractions and relaxations move along the adherent surface and the animal moves slowly along.
Some sea urchins also use their spines for benthic locomotion.
Crabs typically walk sideways
(a behaviour that gives us the word
''crabwise''). This is because of the articulation of the legs, which makes a sidelong gait more efficient.
However, some crabs walk forwards or backwards, including
raninids, ''
Libinia emarginata
''Libinia emarginata'', the portly spider crab, common spider crab or nine-spined spider crab, is a species of stenohaline crab that lives on the Atlantic coast of North America.
Distribution
''Libinia emarginata'' occurs from Nova Scotia to th ...
'' and ''
Mictyris platycheles
''Mictyris platycheles'' is a species of crab found on mudflats on the east coast of Australia from Tasmania and Victoria to Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Qu ...
''.
Some crabs, notably the
Portunidae
Portunidae is a family of crabs which contains the swimming crabs.
Description
Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong ...
and
Matutidae
Matutidae is a family of crabs, sometimes called ''moon crabs'', adapted for swimming or digging. They differ from the swimming crabs of the family Portunidae in that all five pairs of legs are flattened, rather than just the last pair, as in Por ...
, are also capable of swimming,
the
Portunidae
Portunidae is a family of crabs which contains the swimming crabs.
Description
Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong ...
especially so as their last pair of walking legs are flattened into swimming paddles.
A stomatopod, ''
Nannosquilla decemspinosa
''Nannosquilla decemspinosa'' is a species of long-bodied, short-legged mantis shrimp. It lives in shallow sandy areas along the Pacific coast of Central and South America.
It is most well known because when stranded by a low tide
Tides ...
'', 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.
Aquatic surface
![Velella Bae an Anaon](https://upload.wikimedia.org/wikipedia/commons/5/54/Velella_Bae_an_Anaon.jpg)
''
Velella
''Velella'' is a monospecific genus of hydrozoa in the Porpitidae family. Its only known species is ''Velella velella'', a cosmopolitan free-floating hydrozoan that lives on the surface of the open ocean. It is commonly known by the names sea raf ...
'', the by-the-wind sailor, is a cnidarian with no means of propulsion other than
sailing
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the ''water'' (sailing ship, sailboat, raft, windsurfer, or kitesurfer), on ''ice'' (iceboat) or on ''land'' (land yacht) over a chosen cour ...
. 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
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
, so that the animals tend to sail downwind at a small angle to the wind.
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
Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than water such as razor blades and insects (e.g. water striders) to f ...
of water. Animals that move in such a way include the
water strider
The Gerridae are a family of insects in the order Hemiptera, commonly known as water striders, water skeeters, water scooters, water bugs, pond skaters, water skippers, or water skimmers. Consistent with the classification of the Gerridae as tr ...
. Water striders have legs that are
hydrophobic
In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water.
Hydrophobic molecules tend to be nonpolar and, th ...
, preventing them from interfering with the structure of water.
Another form of locomotion (in which the surface layer is broken) is used by the
basilisk lizard.
Aerial
Active flight
![Brimstone Butterflies Twisting Wings in Courtship Flight](https://upload.wikimedia.org/wikipedia/commons/1/14/Brimstone_Butterflies_Twisting_Wings_in_Courtship_Flight.jpg)
Gravity is the primary obstacle to
flight
Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be a ...
. Because it is impossible for any organism to have a density as low as that of air, flying animals must generate enough
lift
Lift or LIFT may refer to:
Physical devices
* Elevator, or lift, a device used for raising and lowering people or goods
** Paternoster lift, a type of lift using a continuous chain of cars which do not stop
** Patient lift, or Hoyer lift, mobile ...
to ascend and remain airborne. One way to achieve this is with
wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
s, which when moved through the air generate an upward
lift force
A fluid flowing around an object exerts a force on it. Lift is the Vector (geometric)#Vector components, component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag (physics), drag force, which is th ...
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;] there may also be physiological adaptations. Active flight has independently evolved at least four times, in the insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s, pterosaur
Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...
s, bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s, and bat
Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bi ...
s. Insects were the first taxon to evolve flight, approximately 400 million years ago (mya), followed by pterosaurs approximately 220 mya, birds approximately 160 mya, then bats about 60 mya.
Gliding
Rather than active flight, some (semi-) arboreal animals reduce their rate of falling by gliding
Gliding is a recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word ''soaring'' is al ...
. Gliding is heavier-than-air flight without the use of thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...
; the term "volplaning" also refers to this mode of flight in animals. Thelp
Help is a word meaning to give aid or signal distress.
Help may refer to:
Arts, entertainment, and media
Films
* ''Help'' (2010 film), a Bollywood horror film
* ''Help'' (2021 theatrical film), a British psychological thriller film
* '' ...
his 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
Gliding ants are arboreal ants of several different genera that are able to control the direction of their descent when falling from a tree. Living in the rainforest canopy like many other gliders, gliding ants use their gliding to return to the ...
s), reptiles (e.g., banded flying snake
The twin-barred tree snake (''Chrysopelea pelias'') is a species of snake found in Southeast Asia. It is also called the banded flying snake. It can glide, as with all species of its genus ''Chrysopelea'', by stretching the body into a flattened ...
), amphibians (e.g., flying frog
A flying frog (also called a gliding frog) is a frog that has the ability to achieve gliding flight. This means it can descend at an angle less than 45° relative to the horizontal. Other nonflying arboreal frogs can also descend, but only at angle ...
), mammals (e.g., sugar glider
The sugar glider (''Petaurus breviceps'') is a small, omnivorous, arboreal, and nocturnal gliding possum belonging to the marsupial infraclass. The common name refers to its predilection for sugary foods such as sap and nectar and its ability ...
, squirrel glider
The squirrel glider (''Petaurus norfolcensis'') is a nocturnal gliding possum. The squirrel glider is one of the wrist-winged gliders of the genus '' Petaurus''.
Habitat
This species' home range extends from Bordertown near the South Australia ...
).
Some aquatic animals also regularly use gliding, for example, flying fish
The Exocoetidae are a family of marine fish in the order Beloniformes class Actinopterygii, known colloquially as flying fish or flying cod. About 64 species are grouped in seven to nine genera. While they cannot fly in the same way a bird do ...
, octopus and squid. The flights of flying fish are typically around 50 meters (160 ft),Ross Piper
Ross Piper is a British zoologist, entomologist, and explorer.
Biography
Piper's fascination by animals began at a young age through early encounters with a violet ground beetle and the caterpillar of an elephant hawk moth. This early interest ...
(2007), ''Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals'', Greenwood Press
Greenwood Publishing Group, Inc. (GPG), also known as ABC-Clio/Greenwood (stylized ABC-CLIO/Greenwood), is an educational and academic publisher (middle school through university level) which is today part of ABC-Clio. Established in 1967 as Gr ...
. though they can use updrafts at the leading edge of waves to cover distances of up to . To glide upward out of the water, a flying fish moves its tail up to 70 times per second.
Several oceanic squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
, such as the Pacific flying squid, leap out of the water to escape predators, an adaptation similar to that of flying fish. 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. The neon flying squid
The neon flying squid (''Ommastrephes bartramii''), sometimes called the red flying squid, akaika, and red squid is a species of large flying squid in the family Ommastrephidae. They are found in subtropical and temperate oceanic waters globa ...
has been observed to glide for distances over 30 m, at speeds of up to 11.2 m/s.
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. Soaring birds may alternate glides with periods of soaring in rising air. Five principal types of lift are used: thermal
A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example ...
s, ridge lift, lee waves
In meteorology, lee waves are atmospheric stationary waves. The most common form is mountain waves, which are atmospheric internal gravity waves. These were discovered in 1933 by two German glider pilots, Hans Deutschmann and Wolf Hirth, above ...
, convergences and dynamic soaring
Dynamic soaring is a flying technique used to gain energy by repeatedly crossing the boundary between air masses of different velocity. Such zones of wind gradient are generally found close to obstacles and close to the surface, so the technique is ...
.
Examples of soaring flight by birds are the use of:
*Thermals and convergences by raptor
Raptor or RAPTOR may refer to:
Animals
The word "raptor" refers to several groups of bird-like dinosaurs which primarily capture and subdue/kill prey with their talons.
* Raptor (bird) or bird of prey, a bird that primarily hunts and feeds on v ...
s such as vulture
A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture (including Condors). Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and ...
s
*Ridge lift by gull
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
s near cliffs
*Wave lift by migrating birds
*Dynamic effects near the surface of the sea by albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Pacifi ...
es
Ballooning
Ballooning Ballooning may refer to:
* Hot air ballooning
* Balloon (aeronautics)
* Ballooning (spider)
* Ballooning degeneration, a disease
* Memory ballooning
See also
* Balloon (disambiguation)
A balloon is a flexible container for (partially or fully) co ...
is a method of locomotion used by spiders. Certain silk-producing arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s, mostly small or young spiders, secrete a special light-weight gossamer silk for ballooning, sometimes traveling great distances at high altitude.
Terrestrial
Forms of locomotion on land include walking, running, hopping or jumping
Jumping or leaping is a form of locomotion or movement in which an organism or non-living (e.g., robotic) mechanical system propels itself through the air along a ballistic trajectory. Jumping can be distinguished from running, galloping and o ...
, dragging and crawling or slithering. Here friction and buoyancy are no longer an issue, but a strong skeletal
A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...
and muscular
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle ...
framework are required in most terrestrial animals for structural support. Each step also requires much energy to overcome inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...
, and animals can store elastic potential energy
Elastic energy is the mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy occurs when objects are impermanently compressed, s ...
in their tendon
A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...
s to help overcome this. Balance
Balance or balancing may refer to:
Common meanings
* Balance (ability) in biomechanics
* Balance (accounting)
* Balance or weighing scale
* Balance as in equality or equilibrium
Arts and entertainment Film
* ''Balance'' (1983 film), a Bulgarian ...
is also required for movement on land. Human infant
An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...
s learn to crawl
Crawl, The Crawl, or crawling may refer to:
Biology
* Crawling (human), any of several types of human quadrupedal gait
* Limbless locomotion, the movement of limbless animals over the ground
* Undulatory locomotion, a type of motion characterize ...
first before they are able to stand on two feet, which requires good coordination as well as physical development. Humans are bipedal
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' ...
animals, standing on two feet and keeping one on the ground at all times while walking
Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults o ...
. When running
Running is a method of terrestrial locomotion allowing humans and other animals to move rapidly on foot. Running is a type of gait characterized by an aerial phase in which all feet are above the ground (though there are exceptions). This is ...
, only one foot
The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...
is on the ground at any one time at most, and both leave the ground briefly. At higher speeds momentum
In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass an ...
helps keep the body upright, so more energy can be used in movement.
Jumping
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
Kangaroos are four marsupials from the family Macropodidae (macropods, meaning "large foot"). In common use the term is used to describe the largest species from this family, the red kangaroo, as well as the antilopine kangaroo, eastern gre ...
and other macropods, rabbit
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...
, hare
Hares and jackrabbits are mammals belonging to the genus ''Lepus''. They are herbivores, and live solitarily or in pairs. They nest in slight depressions called forms, and their young are able to fend for themselves shortly after birth. The ge ...
, jerboa
Jerboas (from ar, جربوع ') are hopping desert rodents found throughout North Africa and Asia, and are members of the family Dipodidae. They tend to live in hot deserts.
When chased, jerboas can run at up to . Some species are preyed on b ...
, hopping mouse
A hopping mouse is any of about ten different Australian native mice in the genus ''Notomys''. They are rodents, not marsupials, and their ancestors are thought to have arrived from Asia about 5 million years ago.
All are brown or fawn, fading ...
, and kangaroo rat
Kangaroo rats, small mostly nocturnal rodents of genus ''Dipodomys'', are native to arid areas of western North America. The common name derives from their bipedal form. They hop in a manner similar to the much larger kangaroo, but developed thi ...
. Kangaroo rats often leap 2 m and reportedly up to 2.75 m at speeds up to almost . 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.] Frogs are, relative to their size, the best jumpers of all vertebrates. The Australian rocket frog, ''Litoria nasuta
The striped rocket frog (''Litoria nasuta''), or in its native range known as the rocket frog, is a species of frog that occurs mostly in coastal areas from northern Western Australia to around Gosford in New South Wales at its southernmost point ...
'', can leap over , more than fifty times its body length.
Peristalsis and looping
Other animals move in terrestrial habitats without the aid of legs. Earthworm
An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...
s crawl by a peristalsis
Peristalsis ( , ) is a radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, which ...
, the same rhythmic contractions that propel food through the digestive tract.
Leech
Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...
es and geometer moth
The geometer moths are moths belonging to the family Geometridae of the insect order Lepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greek ''geo'' γεω (derivative form of or "the earth"), and ''metr ...
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 and the other end 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.
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
Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforest from eastern Bangladesh to Northeast India ...
is specialized for arboreal
Arboreal locomotion is the Animal locomotion, locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. Th ...
movement, travelling rapidly by brachiation
Brachiation (from "brachium", Latin for "arm"), or arm swinging, 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 ...
(see below
Below may refer to:
*Earth
*Ground (disambiguation)
*Soil
*Floor
*Bottom (disambiguation)
Bottom may refer to:
Anatomy and sex
* Bottom (BDSM), the partner in a BDSM who takes the passive, receiving, or obedient role, to that of the top or ...
).
Others living on rock faces such as in mountain
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited Summit (topography), summit area, and ...
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 caprids
The subfamily Caprinae, also sometimes referred to as the tribe Caprini, is part of the ruminant family Bovidae, and consists of mostly medium-sized bovids. A member of this subfamily is called a caprine, or, more informally, a goat-antelope (a ...
(e.g., Barbary sheep
The Barbary sheep (''Ammotragus lervia''), also known as aoudad (pronounced ɑʊdæd is a species of caprine native to rocky mountains in North Africa. While this is the only species in genus ''Ammotragus'', six subspecies have been describ ...
, yak
The domestic yak (''Bos grunniens''), also known as the Tartary ox, grunting ox or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Kachin Sta ...
, ibex
An ibex (plural ibex, ibexes or ibices) is any of several species of wild goat (genus ''Capra''), distinguished by the male's large recurved horns, which are transversely ridged in front. Ibex are found in Eurasia, North Africa and East Africa. ...
, rocky mountain goat
The mountain goat (''Oreamnos americanus''), also known as the Rocky Mountain goat, is a hoofed mammal endemic to mountainous areas of western North America. A subalpine to alpine species, it is a sure-footed climber commonly seen on cliffs an ...
, 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
The snow leopard (''Panthera uncia''), also known as the ounce, is a Felidae, felid in the genus ''Panthera'' native to the mountain ranges of Central Asia, Central and South Asia. It is listed as Vulnerable species, Vulnerable on the IUCN Red ...
, which being a predator of such caprids also has spectacular balance and leaping abilities, such as ability to leap up to 17m (50ft).
Some light animals are able to climb up smooth sheer surfaces or hang upside down by adhesion
Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another).
The forces that cause adhesion and cohesion can be ...
using suckers. Many insects can do this, though much larger animals such as gecko
Geckos are small, mostly carnivorous lizards that have a wide distribution, found on every continent except Antarctica. Belonging to the infraorder Gekkota, geckos are found in warm climates throughout the world. They range from .
Geckos ar ...
s 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 tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
s, usually have only two functional legs, which some (e.g., ostrich, emu, kiwi) use as their primary, Bipedal
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' ...
, 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
Macropod may refer to:
* Macropodidae, a marsupial family which includes kangaroos, wallabies, tree-kangaroos, pademelons, and several others
* Macropodiformes
The Macropodiformes , also known as macropods, are one of the three suborders of the ...
, kangaroo rats and mice, springhare
''Pedetes'' is a genus of rodent, the springhares, in the family Pedetidae. Members of the genus are distributed across southern and Eastern Africa.
Species
A number of species both extant and extinct are classified in the genus ''Pedetes''. ...
, hopping mice
A hopping mouse is any of about ten different Australian native mice in the genus ''Notomys''. They are rodents, not marsupials, and their ancestors are thought to have arrived from Asia about 5 million years ago.
All are brown or fawn, fading t ...
, pangolin
Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (, from Ancient Greek ϕολιδωτός – "clad in scales"). The one extant family, the Manidae, has three genera: '' Manis'', '' Phataginus'', and '' Smut ...
s and hominina
Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally ''Australopithecus'' (cladistically including the genera ''Homo'', ''Paranthropus'', and ''Kenyanthropus''), and it typically includes ...
n apes. Bipedalism is rarely found outside terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land (e.g. cats, dogs, ants, spiders), as compared with aquatic animals, which live predominantly or entirely in the water (e.g. fish, lobsters, octopuses), and amphibians, ...
s—though at least two types of octopus
An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttle ...
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.
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
Tripedalism (from the Latin tri = three + ped = foot) is locomotion by the use of three limbs. It has been said that parrots ( Psittaciformes) display tripedalism during climbing gaits, which was tested and proven in a 2022 paper on the subject, m ...
locomotion in animals.
Many familiar animals are quadrupedal
Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...
, walking or running on four legs. A few birds use quadrupedal movement in some circumstances. For example, the shoebill
The shoebill (''Balaeniceps rex'') also known as the whalebill, whale-headed stork or shoe-billed stork, is a very large long-legged wading bird. It derives its name from its enormous shoe-shaped bill. It has a somewhat stork-like overall form ...
sometimes uses its wings to right itself after lunging at prey. The newly hatched hoatzin
The hoatzin ( ) or hoactzin ( ), (''Opisthocomus hoazin''), is the only species in the order Opisthocomiformes. It is a species of tropical bird found in swamps, riparian forests, and mangroves of the Amazon and the Orinoco basins in South Ameri ...
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. These claws are gone by the time the bird reaches adulthood.
A relatively few animals use five limbs for locomotion. Prehensile
Prehensility is the quality of an appendage or organ (anatomy), organ that has Adaptation (biology), adapted for grasping or holding. The word is derived from the Latin term ''prehendere'', meaning "to grasp". The ability to grasp is likely der ...
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 do not use the front legs for walking.
Arachnid
Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroon ...
s have eight legs. Most arachnids lack extensor
In anatomy, extension is a movement of a joint that increases the angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extendin ...
muscles in the distal
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
joints of their appendages. Spiders and whipscorpion
Thelyphonida is an arachnid order comprising invertebrates commonly known as whip scorpions or vinegaroons (also spelled vinegarroons and vinegarones). They are often called uropygids in the scientific community based on an alternative name for ...
s extend their limbs hydraulically using the pressure of their hemolymph
Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...
. Solifuge
Solifugae is an Order (biology), order of animals in the Class (biology), class Arachnida known variously as camel spiders, wind scorpions, sun spiders, or solifuges. The order includes more than 1,000 described species in about 147 genus, gener ...
s and some harvestmen
The Opiliones (formerly Phalangida) are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. , over 6,650 species of harvestmen have been discovered worldwide, although the total number of ext ...
extend their knees by the use of highly elastic thickenings in the joint cuticle.[ ]Scorpion
Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always end ...
s, pseudoscorpion
Pseudoscorpions, also known as false scorpions or book scorpions, are small, scorpion-like arachnids belonging to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida.
Pseudoscorpions are generally beneficial to humans sin ...
s and some harvestmen have evolved muscles that extend two leg joints (the femur-patella and patella-tibia joints) at once.
The scorpion ''Hadrurus arizonensis
''Hadrurus arizonensis'', the giant desert hairy scorpion, giant hairy scorpion, or Arizona Desert hairy scorpion is a large scorpion found in North America. Description
''H. arizonensis'' is the largest scorpion in North America, and one of th ...
'' 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.
Centipedes and millipedes have many sets of legs that move in metachronal rhythm
A metachronal rhythm or metachronal wave refers to wavy movements produced by the sequential action (as opposed to synchronized) of structures such as cilia, segments of worms, or legs. These movements produce the appearance of a travelling wave. ...
. Some echinoderms locomote using the many tube feet
Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on britt ...
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. 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. Some multi-armed, fast-moving starfish such as the sunflower seastar
''Pycnopodia helianthoides'', commonly known as the sunflower sea star, is a large sea star found in the northeast Pacific. The only species of its genus, it is among the largest sea stars in the world, with a maximum arm span of . Adult sunflow ...
(''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. Most starfish cannot move quickly, a typical speed being that of the leather star
The leather star (''Dermasterias imbricata'') is a sea star in the family Asteropseidae found at depths to off the western seaboard of North America. It was first described to science by Adolph Eduard Grube in 1857.
Description
The leather st ...
(''Dermasterias imbricata''), which can manage just in a minute. Some burrowing species from the genera ''Astropecten
''Astropecten'' is a genus of sea stars of the family Astropectinidae.
Identification
These sea stars are similar one to each other and it can be difficult to determine with certainty the species only from a photograph. To have a certain d ...
'' and ''Luidia
''Luidia'' is a genus of starfish in the Family (biology), family Luidiidae in which it is the only genus. Species of the family have a cosmopolitan distribution.
Characteristics
Members of the genus are characterised by having long arms with ...
'' 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
''Luidia foliolata'', the sand star, is a species of starfish in the family Luidiidae found in the northeastern Pacific Ocean on sandy and muddy seabeds at depths to about .
Description
The sand star has a small disc and five long, flattened a ...
'') can travel at a speed of per minute. Sunflower starfish are quick, efficient hunters, moving at a speed of using 15,000 tube feet.
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
Basiliscus ( grc-gre, Βασιλίσκος, Basilískos; died 476/477) was Eastern Roman emperor from 9 January 475 to August 476. He became in 464, under his brother-in-law, Emperor Leo (457–474). Basiliscus commanded the army for an inva ...
'' 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 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 m. 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." 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
''Cebrennus rechenbergi'', also known as the Moroccan flic-flac spider and cartwheeling spider, is a species of huntsman spider indigenous to the sand dunes of the Erg Chebbi desert in Morocco. If provoked or threatened it can escape by doubli ...
'') uses a series of rapid, acrobatic flic-flac
Because ballet became formalized in France, a significant part of ballet terminology is in the French language.
A
À la seconde
() (Literally "to second") If a step is done "à la seconde," it is done to the side. 'Second position'. It can also ...
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. This behaviour is different than other huntsman spiders, such as ''Carparachne aureoflava
The wheel spider or golden wheel spider (''Carparachne aureoflava''), is a huntsman spider native to the Namib Desert of Southern Africa. This spider should not be confused with '' Leucorchestris arenicola'', a spider sharing the same common nam ...
'' from the Namib Desert
The Namib ( ; pt, Namibe) is a coastal desert in Southern Africa. The name is of Khoekhoegowab origin and means "vast place". According to the broadest definition, the Namib stretches for more than along the Atlantic coasts of Angola, Namib ...
, which uses passive cartwheeling
A cartwheel is a sideways rotary movement of the body. It is performed by bringing the hands to the floor one at a time while the body inverts. The legs travel over the body trunk while one or both hands are on the floor, and then the feet ret ...
as a form of locomotion. The flic-flac spider can reach speeds of up to 2 m/s using forward or back flips to evade threats.
Subterranean
Some animals move through solids such as soil by burrowing using peristalsis
Peristalsis ( , ) is a radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, which ...
, as in earthworms
An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...
, or other methods. In loose solids such as sand some animals, such as the golden mole
Golden moles are small insectivorous burrowing mammals endemic to Sub-Saharan Africa. They comprise the family Chrysochloridae and as such they are taxonomically distinct from the true moles, family Talpidae, and other mole-like families, all o ...
, marsupial mole
Marsupial moles, the Notoryctidae , are highly specialized marsupial mammals, known from two species found at the Australian interior.
* ''Notoryctes typhlops'' (southern marsupial mole, known as the ''itjaritjari'' by the Pitjantjatjara and Yan ...
, and the pink fairy armadillo, are able to move more rapidly, "swimming" through the loose substrate. Burrowing animals include moles Moles can refer to:
* Moles de Xert, a mountain range in the Baix Maestrat comarca, Valencian Community, Spain
* The Moles (Australian band)
*The Moles, alter ego of Scottish band Simon Dupree and the Big Sound
People
*Abraham Moles, French engin ...
, ground squirrels
Ground squirrels are members of the squirrel family of rodents ( Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known ...
, naked mole-rat
The naked mole-rat (''Heterocephalus glaber''), also known as the sand puppy, is a burrowing rodent native to the Horn of Africa and parts of Kenya, notably in Somali regions. It is closely related to the blesmols and is the only species in th ...
s, tilefish
250px, Blue blanquillo, ''Malacanthus latovittatus''
Tilefishes are mostly small perciform marine fish comprising the family Malacanthidae. They are usually found in sandy areas, especially near coral reefs.
Commercial fisheries exist for th ...
, and mole cricket
Mole crickets are members of the insect family Gryllotalpidae, in the order Orthoptera (grasshoppers, locusts, and crickets). Mole crickets are cylindrical-bodied, fossorial insects about long as adults, with small eyes and shovel-like fore ...
s.
Arboreal locomotion
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. Furthermore, many of these same principles may be applied to climbing without trees, such as on rock piles or mountains. The earliest known tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
with specializations that adapted it for climbing trees was ''Suminia
''Suminia'' is an extinct genus of basal anomodont that lived during the Tatarian age of the late Permian, spanning approximately from 268-252 Ma.Rybczynski N. 2000. Cranial anatomy and phylogenetic position of Suminia getmanovi, a basal anomodon ...
'', a synapsid
Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes reptil ...
of the late Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
, about 260 million years ago. Some invertebrate animals are exclusively arboreal in habitat, for example, the tree snail Tree snail is a common name that is applied to various kinds of tropical air-breathing land snails, pulmonate gastropod mollusks that have shells, and that live in trees, in other words, are exclusively arboreal in habitat.
Some other species of a ...
.
Brachiation
Brachiation (from "brachium", Latin for "arm"), or arm swinging, 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 ...
(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
Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforest from eastern Bangladesh to Northeast India ...
s and siamang
The siamang (, ; ''Symphalangus syndactylus'') is an arboreal, black-furred gibbon native to the forests of Indonesia, Malaysia, and Thailand. The largest of the gibbons, the siamang can be twice the size of other gibbons, reaching in height, a ...
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 Suspensory behaviour is a form of arboreal locomotion or a feeding behavior that involves hanging or suspension of the body below or among tree branches. This behavior enables faster travel while reducing path lengths to cover more ground when trave ...
s by using their prehensile tail
A prehensile tail is the tail of an animal that has adapted to grasp or hold objects. Fully prehensile tails can be used to hold and manipulate objects, and in particular to aid arboreal creatures in finding and eating food in the trees. If the ta ...
, which acts as a fifth grasping hand.
Energetics
Animal locomotion requires energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat a ...
to overcome various forces including friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:
*Dry friction is a force that opposes the relative lateral motion of t ...
, drag, inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...
and gravity
In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...
, although the influence of these depends on the circumstances. In terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
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
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the p ...
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
Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be a ...
, and the aerodynamic
Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
ally efficient body shapes of flying bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
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 third law of motion
Newton's laws of motion are three basic Scientific law, laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows:
# A body remains at re ...
is widely used in the study of animal locomotion: if at rest, to move forwards an animal must push something backwards. Terrestrial animals must push the solid ground, swimming and flying animals must push against a fluid
In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...
(either water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
or air
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...
). 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
The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force applied. ...
) 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
Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency. Di ...
. The net cost of transport of swimming is lowest, followed by flight, with terrestrial limbed locomotion being the most expensive per unit distance. 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
Human body weight is a person's Mass versus weight, mass or weight.
Strictly speaking, body weight is the measurement of weight without items located on the person. Practically though, body weight may be measured with clothes on, but without shoe ...
—heavier animals, though using more total energy, require less energy ''per unit mass'' to move. Physiologists
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical an ...
generally measure energy use by the amount of oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
consumed, or the amount of carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
produced, in an animal's respiration
Respiration may refer to:
Biology
* Cellular respiration, the process in which nutrients are converted into useful energy in a cell
** Anaerobic respiration, cellular respiration without oxygen
** Maintenance respiration, the amount of cellula ...
. 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
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...
, such as deer mice
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...
, the cost of transport has also been measured during voluntary wheel running.
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
Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula .
For human consumption, sucrose is extracted and refined ...
content of viscous nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
off for the energetic benefits of warmer, less concentrated nectar, which also reduces their consumption and flight time.
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
Motility is the ability of an organism to move independently, using metabolic energy.
Definitions
Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ...
.
Hydrozoans
The Portuguese man o' war
The Portuguese man o' war (''Physalia physalis''), also known as the man-of-war, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is considered to be the same species as the Pacific man o' war or blue bottle, which is ...
(''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.
Mollusca
The violet sea-snail (''Janthina janthina'') uses a buoyant foam raft stabilized by amphiphilic
An amphiphile (from the Greek αμφις amphis, both, and φιλíα philia, love, friendship), or amphipath, is a chemical compound possessing both hydrophilic (''water-loving'', polar) and lipophilic (''fat-loving'') properties. Such a compoun ...
mucins
Mucins () are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most ...
to float at the sea surface.
Arachnids
The wheel spider
The wheel spider or golden wheel spider (''Carparachne aureoflava''), is a huntsman spider native to the Namib Desert of Southern Africa. This spider should not be confused with ''Leucorchestris arenicola'', a spider sharing the same common name ...
(''Carparachne aureoflava'') is a huntsman spider
Huntsman spiders, members of the family Sparassidae (formerly Heteropodidae), are known by this name because of their speed and mode of hunting. They are also called giant crab spiders because of their size and appearance. Larger species sometim ...
approximately 20 mm in size and native to the Namib Desert
The Namib ( ; pt, Namibe) is a coastal desert in Southern Africa. The name is of Khoekhoegowab origin and means "vast place". According to the broadest definition, the Namib stretches for more than along the Atlantic coasts of Angola, Namib ...
of Southern Africa
Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number of ...
. The spider escapes parasitic pompilid wasps by flipping onto its side and cartwheeling
A cartwheel is a sideways rotary movement of the body. It is performed by bringing the hands to the floor one at a time while the body inverts. The legs travel over the body trunk while one or both hands are on the floor, and then the feet ret ...
down sand dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...
s at speeds of up to 44 turns per second. If the spider is on a sloped dune, its rolling speed may be 1 metre per second.
A spider (usually limited to individuals of a small species), or spiderling after hatching, climbs as high as it can, stands on raised legs with its abdomen pointed upwards ("tiptoeing"), and then releases several silk threads from its spinnerets
A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and are ...
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.
Insects
The larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
of ''Cicindela dorsalis
''Habroscelimorpha dorsalis'', commonly known as the eastern beach tiger beetle, is a species of flashy tiger beetle in the family Cicindelidae. It is found in Central America and North America.
Description
The body length is . The head and thor ...
'', 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 in this manner. This remarkable ability may have evolved to help the larva escape predators such as the thynnid wasp ''Methocha
''Methocha'' is a genus of parasitoid wasps in the family Thynnidae.
The species of this genus are found worldwide except in Australia, and attack the larvae of tiger beetles. Females are wingless, and can be mistaken for ants, while males are w ...
''.
Members of the largest subfamily of cuckoo wasps, Chrysidinae
The subfamily Chrysidinae contains those species that are most commonly recognized as cuckoo wasps, being by far the largest and most familiar subfamily. The group contains 3000 species with 48 genera worldwide. They are highly sculptured, with br ...
, are generally kleptoparasite
Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when fo ...
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
Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...
s can jump vertically up to 18 cm and horizontally up to 33 cm; 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.
Crustaceans
Although stomatopod
Mantis shrimp, or stomatopods, are carnivorous marine crustaceans of the order Stomatopoda (). Stomatopods branched off from other members of the class Malacostraca around 340 million years ago. Mantis shrimp typically grow to around in leng ...
s typically display the standard locomotion types as seen in true shrimp
The Caridea, commonly known as caridean shrimp or true shrimp, are an infraorder of shrimp within the order Decapoda. This infraorder contains all species of true shrimp. They are found widely around the world in both fresh and salt water. Many ...
and lobsters
Lobsters are a family (Nephropidae, synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs have claws, including the first pair, ...
, one species, ''Nannosquilla decemspinosa
''Nannosquilla decemspinosa'' is a species of long-bodied, short-legged mantis shrimp. It lives in shallow sandy areas along the Pacific coast of Central and South America.
It is most well known because when stranded by a low tide
Tides ...
'', 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 , but they typically travel less than . Again, the animal initiates the movement but has little control during its locomotion.
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
Remora
The remora (), sometimes called suckerfish, is any of a family (Echeneidae) of ray-finned fish in the order Carangiformes. Depending on species, they grow to long. Their distinctive first dorsal fins take the form of a modified oval, sucker-li ...
s are a family (''Echeneidae'') of ray-finned fish
Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species.
The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...
. They grow to long, and their distinctive first dorsal fin
A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...
s 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. 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 , 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
The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled Organ (anatomy), organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their curren ...
. Some remoras associate primarily with specific host species. They are commonly found attached to sharks, manta ray
Manta rays are large rays belonging to the genus ''Mobula'' (formerly its own genus ''Manta''). The larger species, '' M. birostris'', reaches in width, while the smaller, '' M. alfredi'', reaches . Both have triangular Pectoral fin#AnchPect ...
s, whales, turtles, and dugong
The dugong (; ''Dugong dugon'') is a marine mammal. It is one of four living species of the order Sirenia, which also includes three species of manatees. It is the only living representative of the once-diverse family Dugongidae; its closest m ...
s. Smaller remoras also fasten onto fish such as tuna and swordfish
Swordfish (''Xiphias gladius''), also known as broadbills in some countries, are large, highly migratory predatory fish characterized by a long, flat, pointed bill. They are a popular sport fish of the billfish category, though elusive. Swordfis ...
, and some small remoras travel in the mouths or gills of large manta rays, ocean sunfish
The ocean sunfish or common mola (''Mola mola'') is one of the largest bony fish in the world. It was misidentified as the heaviest bony fish, which was actually a different species, ''Mola alexandrini''. Adults typically weigh between . The spe ...
, swordfish, and sailfish
The sailfish is one or two species of marine fish in the genus ''Istiophorus'', which belong to the family Istiophoridae (marlins). They are predominantly blue to gray in colour and have a characteristically large dorsal fin known as the sa ...
. 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
The anglerfish are fish of the teleost order Lophiiformes (). They are bony fish named for their characteristic mode of predation, in which a modified luminescent fin ray (the esca or illicium) acts as a lure for other fish. The luminescence ...
, when a male finds a female, he bites into her skin, and releases an enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
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
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
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.
Parasites
Many parasites
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...
are transported by their hosts. For example, endoparasites such as tapeworms
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of man ...
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
Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...
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
Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result o ...
can opportunistically hitch a ride on a fly (phoresis
Phoresis or phoresy is a non-permanent, commensalistic interaction in which one organism (a phoront or phoretic) attaches itself to another (the host) solely for the purpose of travel. Phoresis has been observed directly in ticks and mites s ...
) and attempt to find a new host.
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
A walking fish, or ambulatory fish, is a fish that is able to travel over ecoregion#Terrestrial, land for extended periods of time. Some other modes of non-standard fish locomotion include "walking" along the seabed, sea floor, for example, in ha ...
may swim freely or at other times "walk" along the ocean or river floor, but not on land (e.g., the flying gurnard
The flying gurnard (''Dactylopterus volitans''), also known as the helmet gurnard, is a bottom-dwelling fish of tropical to warm temperate waters on both sides of the Atlantic. On the American side, it is found as far north as Massachusetts (ex ...
—which does not actually fly—and batfishes of the family Ogcocephalidae). Amphibious fish
Amphibious fish are fish that are able to leave water for extended periods of time. About 11 distantly related genera of fish are considered amphibious. This suggests that many fish genera independently evolved amphibious traits, a process known ...
, 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
Undulatory locomotion is the type of motion characterized by wave-like movement patterns that act to propel an animal forward. Examples of this type of gait include crawling in snakes, or swimming in the lamprey. Although this is typically the ...
, tripod
A tripod is a portable three-legged frame or stand, used as a platform for supporting the weight and maintaining the stability of some other object. The three-legged (triangular stance) design provides good stability against gravitational loads ...
-like walking (using paired fin
A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...
s and tail
The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...
), and jumping. Many of these locomotory modes incorporate multiple combinations of pectoral
Pectoral may refer to:
* The chest region and anything relating to it.
* Pectoral cross, a cross worn on the chest
* a decorative, usually jeweled version of a gorget
* Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt
* Pectoralis ...
, pelvic
The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton).
The ...
and tail fin movement. Examples include eel
Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...
s, mudskippers
Mudskippers are any of the 23 extant species of amphibious fish from the subfamily Oxudercinae of the goby family Oxudercidae. They are known for their unusual body shapes, preferences for semiaquatic habitats, limited terrestrial locomotion and ...
and the walking catfish
The walking catfish (''Clarias batrachus'') is a species of freshwater airbreathing catfish native to Southeast Asia. It is named for its ability to "walk" and wiggle across dry land, to find food or suitable environments. While it does not trul ...
. Flying fish
The Exocoetidae are a family of marine fish in the order Beloniformes class Actinopterygii, known colloquially as flying fish or flying cod. About 64 species are grouped in seven to nine genera. While they cannot fly in the same way a bird do ...
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 . They can travel at speeds of more than .[ Maximum altitude is above the surface of the sea.] Some accounts have them landing on ships' decks.[
]
Marine mammals
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. This type of travel is known as "porpoising". Other reasons for dolphins and porpoises performing porpoising include orientation, social displays, fighting, non-verbal communication
Nonverbal communication (NVC) is the transmission of messages or signals through a nonverbal platform such as eye contact, facial expressions, gestures, posture, and body language. It includes the use of social cues, kinesics, distance (proxemic ...
, entertainment and attempting to dislodge parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s. 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
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
Diving birds are birds which plunge into the water to catch fish or other prey. Such birds may enter the water from flight, such as pelicans, gannets and tropicbirds; or they may dive from the surface of the water, such as the diving ducks, cormora ...
also use diving locomotion (e.g., dippers, auks). Some birds (e.g., ratites
A ratite () is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites.
The systematics o ...
) have lost the primary locomotion of flight. The largest of these, ostrich
Ostriches are large flightless birds of the genus ''Struthio'' in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There are ...
es, when being pursued by a predator, have been known to reach speeds over , and can maintain a steady speed of , which makes the ostrich the world's fastest two-legged animal: Ostriches can also locomote by swimming. 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
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive ...
are exclusively marine and tend to live in shallow and tidal waters. They have two nekton
Nekton or necton (from the ) refers to the actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms ...
ic (active swimming) larval stages, but as adults, they are sessile
Sessility, or sessile, may refer to:
* Sessility (motility), organisms which are not able to move about
* Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant
* Sessility (medicine), tumors and polyps that ...
(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
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
Ambush predators or sit-and-wait predators are carnivorous animals that capture or trap prey via stealth, luring or by (typically instinctive) strategies utilizing an element of surprise. Unlike pursuit predators, who chase to capture prey us ...
, social predation and grazing
In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...
. Aquatic methods include filterfeeding, grazing, ram feeding, suction feeding, protrusion and pivot feeding. Other methods include parasitism
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...
and parasitoid
In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...
ism.
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.
Galleries
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
Further reading
* Robert McNeill Alexander, McNeill Alexander, Robert. (2003) ''Principles of Animal Locomotion''. Princeton University Press, Princeton, N.J.
External links
Beetle Orientation
{{Authority control
Animal locomotion,
Ethology
Zoology
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