![Greylag Geese (Anser anser) in flight, Cley, Norfolk 1700](https://upload.wikimedia.org/wikipedia/commons/7/7c/Greylag_Geese_%28Anser_anser%29_in_flight%2C_Cley%2C_Norfolk_1700.jpg)
A number of
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 are capable of aerial locomotion, either by powered
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 ...
or by
gliding. This trait has appeared by
evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
many times, without any single common ancestor. Flight has evolved at least four times in separate animals:
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 ...
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 ...
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 lightweig ...
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 ...
s. Gliding has evolved on many more occasions. Usually the development is to aid
canopy
Canopy may refer to:
Plants
* Canopy (biology), aboveground portion of plant community or crop (including forests)
* Canopy (grape), aboveground portion of grapes
Religion and ceremonies
* Baldachin or canopy of state, typically placed over an ...
animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among
rainforest animals, especially in the rainforests in
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
(most especially
Borneo
Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and ea ...
) where the
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s are tall and widely spaced. Several species of
aquatic animal
An aquatic animal is any animal, whether invertebrate or vertebrate, that lives in water for most or all of its lifetime. Many insects such as mosquitoes, mayflies, dragonflies and caddisflies have aquatic larvae, with winged adults. Aquatic ani ...
s, and a few
amphibians and
reptiles have also evolved this gliding flight ability, typically as a means of evading predators.
Types
Animal aerial locomotion can be divided into two categories: powered and unpowered. In unpowered modes of locomotion, the animal uses aerodynamic forces exerted on the body due to wind or falling through the air. In powered flight, the animal uses muscular power to generate aerodynamic forces to climb or to maintain steady, level flight. Those who can find air that is rising faster than they are falling can gain altitude by
soaring
Soaring may refer to:
* Gliding, in which pilots fly unpowered aircraft known as gliders or sailplanes
* Lift (soaring), a meteorological phenomenon used as an energy source by some aircraft and birds
* ''Soaring'' (magazine), a magazine produced ...
.
Unpowered
These modes of locomotion typically require an animal start from a raised location, converting that
potential energy into
kinetic energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acc ...
and using aerodynamic forces to control trajectory and angle of descent. Energy is continually lost to drag without being replaced, thus these methods of locomotion have limited range and duration.
*
Falling
Falling or fallin' may refer to:
*Falling (physics), movement due to gravity
*Falling (accident)
*Falling (execution)
*Falling (sensation)
People
* Christine Falling (born 1963), American serial killer who murdered six children
Books
* ''Fall ...
: decreasing altitude under the force of
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 ...
, using no adaptations to increase
drag or provide
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, mobil ...
.
*
Parachuting: falling at an angle greater than 45° from the
horizontal with adaptations to increase drag forces. Very small animals may be carried up by the
wind
Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ho ...
. Some gliding animals may use their gliding membranes for drag rather than lift, to safely descend.
*
Gliding flight
Gliding flight is heavier-than-air flight without the use of thrust; the term volplaning also refers to this mode of flight in animals. It is employed by gliding animals and by aircraft such as gliders. This mode of flight involves flying a s ...
: falling at an angle less than 45° from the horizontal with lift from adapted
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. ...
membranes. This allows slowly falling directed horizontal movement, with streamlining to decrease drag forces for aerofoil efficiency and often with some maneuverability in air. Gliding animals have a lower
aspect ratio (wing length/breadth) than true flyers.
Powered flight
Powered
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 ...
has evolved at least four times: first 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 ...
s, then in
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 ...
s, next in
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 lightweig ...
s, and last in
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 ...
s. Studies on theropod dinosaurs do suggest multiple (≥3) independent acquisitions of powered flight however,
and a recent study proposes independent acquisitions amidst the different bat clades as well. Powered flight uses muscles to generate
aerodynamic force
In fluid mechanics, an aerodynamic force is a force exerted on a body by the air (or other gas) in which the body is immersed, and is due to the relative motion between the body and the gas.
Force
There are two causes of aerodynamic force:
...
, which allows the animal to produce lift and thrust. The animal may ascend without the aid of rising air.
Externally powered
Ballooning and soaring are not powered by muscle, but rather by external aerodynamic sources of energy: the wind and rising thermals, respectively. Both can continue as long as the source of external power is present. Soaring is typically only seen in species capable of powered flight, as it requires extremely large wings.
*
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 ...
: being carried up into the air from the aerodynamic effect on long strands of silk in the wind. Certain silk-producing
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...
s, mostly small or young spiders, secrete a special light-weight
gossamer silk for ballooning, sometimes traveling great distances at high altitude.
*
Soaring
Soaring may refer to:
* Gliding, in which pilots fly unpowered aircraft known as gliders or sailplanes
* Lift (soaring), a meteorological phenomenon used as an energy source by some aircraft and birds
* ''Soaring'' (magazine), a magazine produced ...
: gliding in rising or otherwise moving air that requires specific physiological and morphological adaptations that can sustain the animal aloft without flapping its wings. The rising air is due to
thermals
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 ...
,
ridge lift or
other meteorological features. Under the right conditions, soaring creates a gain of altitude without expending energy. Large wingspans are needed for efficient soaring.
Many species will use multiple of these modes at various times; a
hawk will use powered flight to rise, then soar on thermals, then descend via free-fall to catch its prey.
Evolution and ecology
Gliding and parachuting
While gliding occurs independently from powered flight, it has some ecological advantages of its own as it is the simplest form of flight.
Gliding is a very
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 hea ...
-efficient way of travelling from tree to tree. Although moving through the canopy running along the branches may be less energetically demanding, the faster transition between trees allows for greater foraging rates in a particular patch.
Glide ratios can be dependent on size and current behavior. Higher foraging rates are supported by low glide ratios as smaller foraging patches require less gliding time over shorter distances and greater amounts of food can be acquired in a shorter time period.
Low ratios are not as energy efficient as the higher ratios,
but an argument made is that many gliding animals eat low energy foods such as leaves and are restricted to gliding because of this, whereas flying animals eat more high energy foods such as
fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
s,
nectar, and insects.
Mammals tend to rely on lower glide ratios to increase the amount of time foraging for lower energy food.
An equilibrium glide, achieving a constant airspeed and glide angle, is harder to obtain as animal size increases. Larger animals need to glide from much higher heights and longer distances to make it energetically beneficial.
Gliding is also very suitable for predator avoidance, allowing for controlled targeted landings to safer areas
. In contrast to flight, gliding has evolved independently many times (more than a dozen times among extant vertebrates); however these groups have not radiated nearly as much as have groups of flying animals.
Worldwide, the distribution of gliding animals is uneven, as most inhabit rain forests in
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...
. (Despite seemingly suitable rain forest habitats, few gliders are found in India or New Guinea and none in Madagascar.) Additionally, a variety of gliding vertebrates are found in
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, a family of
hylids (
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 ...
s) lives in
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
and several species of gliding squirrels are found in the forests of northern Asia and North America.
Various factors produce these disparities. In the forests of Southeast Asia, the dominant canopy trees (usually
dipterocarp
Dipterocarpaceae is a family of 16 genera and about 695 known species of mainly tropical lowland rainforest trees. The family name, from the type genus ''Dipterocarpus'', is derived from Greek (''di'' = two, ''pteron'' = wing and ''karpos'' = f ...
s) are taller than the canopy trees of the other forests. Forest structure and distance between trees are influential in the development of gliding within varying species.
A higher start provides a competitive advantage of further glides and farther travel. Gliding predators may more efficiently search for prey. The lower abundance of insect and small vertebrate prey for carnivorous animals (such as lizards) in Asian forests may be a factor.
[ In Australia, many mammals (and all mammalian gliders) possess, to some extent, prehensile tails. Globally, smaller gliding species tend to have feather-like tails and larger species have fur covered round bushy tails,] but smaller animals tend to rely on parachuting rather than developing gliding membranes. The gliding membranes, patagium, are classified in the 4 groups of propatagium, digipatagium, plagiopatagium and uropatagium. These membranes consist of two tightly bounded layers of skin connected by muscles and connective tissue between the fore and hind limbs.
Powered flight evolution
Powered flight has evolved unambiguously only four times— birds, bats
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 bir ...
, pterosaurs, and insects
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 of j ...
(though see above for possible independent acquisitions within bird and bat groups). In contrast to gliding, which has evolved more frequently but typically gives rise to only a handful of species, all three extant groups of powered flyers have a huge number of species, suggesting that flight is a very successful strategy once evolved. 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 ...
s, after rodent
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 n ...
s, have the most species of any mammalian order, about 20% of all mammalian species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate 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 lightweig ...
s have the most species of any class of terrestrial vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
s. Finally, 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 ...
s (most of which fly at some point in their life cycle) have more species than all other animal groups combined.
The evolution of flight is one of the most striking and demanding in animal evolution, and has attracted the attention of many prominent scientists and generated many theories. Additionally, because flying animals tend to be small and have a low mass (both of which increase the surface-area-to-mass ratio), they tend to fossilize infrequently and poorly compared to the larger, heavier-boned terrestrial species they share habitat with. Fossils of flying animals tend to be confined to exceptional fossil deposits formed under highly specific circumstances, resulting in a generally poor fossil record, and a particular lack of transitional forms. Furthermore, as fossils do not preserve behavior or muscle, it can be difficult to discriminate between a poor flyer and a good glider.
Insects were the first to evolve flight, approximately 350 million years ago. The developmental origin of the insect wing remains in dispute, as does the purpose prior to true flight. One suggestion is that wings initially evolved from tracheal gill structures and were used to catch the wind for small insects that live on the surface of the water, while another is that they evolved from paranotal lobes or leg structures and gradually progressed from parachuting, to gliding, to flight for originally arboreal insects.
Pterosaurs were the next to evolve flight, approximately 228 million years ago. These reptiles were close relatives of the dinosaurs, and reached enormous sizes, with some of the last forms being the largest flying animals ever to inhabit the Earth, having wingspans of over 9.1 m (30 ft). However, they spanned a large range of sizes, down to a 250 mm (10 in) wingspan in '' Nemicolopterus''.
Birds have an extensive fossil record, along with many forms documenting both their evolution from small theropod dinosaurs and the numerous bird-like forms of theropod which did not survive the mass extinction at the end of the Cretaceous. Indeed, '' Archaeopteryx'' is arguably the most famous transitional fossil in the world, both due to its mix of reptilian and avian anatomy and the luck of being discovered only two years after Darwin's publication of ''On the Origin of Species
''On the Origin of Species'' (or, more completely, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''),The book's full original title was ''On the Origin of Species by Me ...
''. However, the ecology of this transition is considerably more contentious, with various scientists supporting either a "trees down" origin (in which an arboreal
Arboreal locomotion is the 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. The habitats pose nu ...
ancestor evolved gliding, then flight) or a " ground up" origin (in which a fast-running terrestrial ancestor used wings for a speed boost and to help catch prey).
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 ...
s are the most recent to evolve (about 60 million years ago), most likely from a fluttering ancestor, though their poor fossil record has hindered more detailed study.
Only a few animals are known to have specialised in soaring: the larger of the extinct 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 ...
s, and some large birds. Powered flight is very energetically expensive for large animals, but for soaring their size is an advantage, as it allows them a low wing loading, that is a large wing area relative to their weight, which maximizes lift. Soaring is very energetically efficient.
Biomechanics
Gliding and parachuting
During a free-fall with no aerodynamic forces, the object accelerates due to gravity, resulting in increasing velocity as the object descends. During parachuting, animals use the aerodynamic forces on their body to counteract the force or gravity. Any object moving through air experiences a drag force that is proportion to surface area and to velocity squared, and this force will partially counter the force of gravity, slowing the animal's descent to a safer speed. If this drag is oriented at an angle to the vertical, the animal's trajectory will gradually become more horizontal, and it will cover horizontal as well as vertical distance. Smaller adjustments can allow turning or other maneuvers. This can allow a parachuting animal to move from a high location on one tree to a lower location on another tree nearby. Specifically in gliding mammals, there are 3 types of gliding paths respectively being S glide, J glide, and "straight-shaped" glides where species either gain altitude post launch then descend, rapidly decrease height before gliding, and maintaining a constant angled descent.
During gliding, lift plays an increased role. Like drag, lift is proportional to velocity squared. Gliding animals will typically leap or drop from high locations such as trees, just as in parachuting, and as gravitational acceleration increases their speed, the aerodynamic forces also increase. Because the animal can utilize lift and drag to generate greater aerodynamic force, it can glide at a shallower angle than parachuting animals, allowing it to cover greater horizontal distance in the same loss of altitude, and reach trees further away. Successful flights for gliding animals are achieved through 5 steps: preparation, launch, glide, braking, and landing. Gliding species are better able to control themselves mid-air, with the tail acting as a rudder, making it capable to pull off banking movements or U-turns during flight. During landing, arboreal mammals will extend their fore and hind limbs in front of itself to brace for landing and to trap air in order to maximize air resistance and lower impact speed.
Powered flight
Unlike most air vehicles, in which the objects that generate lift (wings) and thrust (engine or propeller) are separate and the wings remain fixed, flying animals use their wings to generate both lift and thrust by moving them relative to the body. This has made the flight of organisms considerably harder to understand than that of vehicles, as it involves varying speeds, angles, orientations, areas, and flow patterns over the wings.
A 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 lightweig ...
or 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 ...
flying through the air at a constant speed moves its wings up and down (usually with some fore-aft movement as well). Because the animal is in motion, there is some airflow relative to its body which, combined with the velocity of its wings, generates a faster airflow moving over the wing. This will generate lift force vector pointing forwards and upwards, and a drag force vector pointing rearwards and upwards. The upwards components of these counteract gravity, keeping the body in the air, while the forward component provides thrust to counteract both the drag from the wing and from the body as a whole. 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 ...
flight likely worked in a similar manner, though no living pterosaurs remain for study.
Insect flight
Insects are the only group of invertebrates that have evolved wings and flight. Insects first flew in the Carboniferous, some 350 to 400 million years ago, making them the first animals to evolve flight. Wings may have evolved from appenda ...
is considerably different, due to their small size, rigid wings, and other anatomical differences. Turbulence and vortices play a much larger role in insect flight, making it even more complex and difficult to study than the flight of vertebrates. There are two basic aerodynamic models of insect flight. Most insects use a method that creates a spiralling leading edge
The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...
vortex
In fluid dynamics, a vortex ( : vortices or vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices form in stirred fluids, and may be observed in smoke rings, whirlpools in ...
. Some very small insects use the fling-and-clap or Weis-Fogh mechanism in which the wings clap together above the insect's body and then fling apart. As they fling open, the air gets sucked in and creates a vortex over each wing. This bound vortex then moves across the wing and, in the clap, acts as the starting vortex for the other wing. Circulation and lift are increased, at the price of wear and tear on the wings.
Limits and extremes
Flying and soaring
* Largest. The largest known flying animal was formerly thought to be '' Pteranodon'', a 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 ...
with a wingspan of up to . However, the more recently discovered azhdarchid
Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cre ...
pterosaur '' Quetzalcoatlus'' is much larger, with estimates of the wingspan ranging from . Some other recently discovered azhdarchid pterosaur species, such as '' Hatzegopteryx'', may have also wingspans of a similar size or even slightly larger. Although it is widely thought that ''Quetzalcoatlus'' reached the size limit of a flying animal, the same was once said of ''Pteranodon''. The heaviest living flying animals are the kori bustard
The kori bustard (''Ardeotis kori'') is the largest flying bird native to Africa. It is a member of the bustard family, which all belong to the order Otidiformes and are restricted in distribution to the Old World. It is one of the four species ( ...
and the great bustard
The great bustard (''Otis tarda'') is a bird in the bustard family, the only member of the genus ''Otis''. It breeds in open grasslands and farmland from northern Morocco, South and Central Europe, to temperate Central and East Asia. European po ...
with males reaching . The wandering albatross
The wandering albatross, snowy albatross, white-winged albatross or goonie (''Diomedea exulans'') is a large seabird from the family Diomedeidae, which has a circumpolar range in the Southern Ocean. It was the last species of albatross to be desc ...
has the greatest wingspan of any living flying animal at . Among living animals which fly over land, the Andean condor
The Andean condor (''Vultur gryphus'') is a giant South American Cathartid vulture and is the only member of the genus ''Vultur''. Found in the Andes mountains and adjacent Pacific coasts of western South America, the Andean condor is the larg ...
and the marabou stork have the largest wingspan at . Studies have shown that it is physically possible for flying animals to reach wingspans, but there is no firm evidence that any flying animal, not even the azhdarchid pterosaurs, got that large.
* Smallest. There is no minimum size for getting airborne. Indeed, there are many bacteria floating in the atmosphere that constitute part of the aeroplankton
Aeroplankton (or aerial plankton) are tiny lifeforms that float and drift in the air, carried by wind. Most of the living things that make up aeroplankton are very small to microscopic in size, and many can be difficult to identify because of ...
. However, to move about under one's own power and not be overly affected by the wind requires a certain amount of size. The smallest flying vertebrates are the bee hummingbird
The bee hummingbird, zunzuncito or Helena hummingbird (''Mellisuga helenae'') is a species of hummingbird, native to the island of Cuba in the Caribbean. It is the world's smallest bird.
Description
The bee hummingbird is the smallest living ...
and the bumblebee bat
Kitti's hog-nosed bat (''Craseonycteris thonglongyai''), also known as the bumblebee bat, is a near-threatened species of bat and the only extant member of the family Craseonycteridae. It occurs in western Thailand and southeast Myanmar, where i ...
, both of which may weigh less than . They are thought to represent the lower size limit for endotherm
An endotherm (from Greek ἔνδον ''endon'' "within" and θέρμη ''thermē'' "heat") is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat released by its internal bodily functions inst ...
flight.
* Fastest. The fastest of all known flying animals is the peregrine falcon, which when diving travels at or faster. The fastest animal in flapping horizontal flight may be the Mexican free-tailed bat
The Mexican free-tailed bat or Brazilian free-tailed bat (''Tadarida brasiliensis'') is a medium-sized bat native to the Americas, so named because its tail can be almost half its total length and is not attached to its uropatagium. It has been ...
, said to attain about based on ground speed by an aircraft tracking device; that measurement does not separate any contribution from wind speed, so the observations could be caused by strong tailwind
A tailwind is a wind that blows in the direction of travel of an object, while a headwind blows against the direction of travel. A tailwind increases the object's speed and reduces the time required to reach its destination, while a headwind has ...
s.
* Slowest. Most flying animals need to travel forward to stay aloft. However, some creatures can stay in the same spot, known as hovering, either by rapidly flapping the wings, as do hummingbirds, hoverflies
Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while ...
, dragonflies
A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...
, and some others, or carefully using thermals, as do some birds of prey
Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predat ...
. The slowest flying non-hovering bird recorded is the American woodcock
The American woodcock (''Scolopax minor''), sometimes colloquially referred to as the timberdoodle, the bogsucker, the hokumpoke, and the Labrador twister, is a small shorebird species found primarily in the eastern half of North America. Woodcoc ...
, at .
* Highest flying. There are records of a Rüppell's vulture
Rüppell's vulture (''Gyps rueppelli''), also called Rüppell's griffon vulture, named after Eduard Rüppell, is a large bird of prey, mainly native to the Sahel region and East Africa. The current population of 22,000 is decreasing due to loss ...
''Gyps rueppelli'', a large vulture, being sucked into a jet engine above Côte d'Ivoire in West Africa. The animal that flies highest most regularly is the bar-headed goose
The bar-headed goose (''Anser indicus'') is a goose that breeds in Central Asia in colonies of thousands near mountain lakes and winters in South Asia, as far south as peninsular India. It lays three to eight eggs at a time in a ground nest. It ...
''Anser indicus'', which migrates directly over the Himalayas
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 10 ...
between its nesting grounds in Tibet
Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa, Taman ...
and its winter quarters in India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. They are sometimes seen flying well above the peak of Mount Everest
Mount Everest (; Tibetic languages, Tibetan: ''Chomolungma'' ; ) is List of highest mountains on Earth, Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border ru ...
at .
Gliding and parachuting
* Most efficient glider. This can be taken as the animal that moves most horizontal distance per metre fallen. Flying squirrels are known to glide up to , but have measured glide ratio
In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficiency under giv ...
of about 2. 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 d ...
have been observed to glide for hundreds of metres on the drafts on the edge of waves with only their initial leap from the water to provide height, but may be obtaining additional lift from wave motion. On the other hand, albatrosses have measured lift–drag ratios of 20, and thus fall just 1 meter for every 20 in still air.
* Most maneuverable glider. Many gliding animals have some ability to turn, but which is the most maneuverable is difficult to assess. Even paradise tree snakes, Chinese gliding frogs, and 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 have been observed as having considerable capacity to turn in the air.
Flying animals
Extant
Insects
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 of j ...
* Pterygota
The Pterygota ( grc, πτερυγωτός, pterugōtós, winged) are a subclass of insects that includes the winged insects. It also includes insect orders that are secondarily wingless (that is, insect groups whose ancestors once had wings b ...
: The first of all animals to evolve flight, they are also the only invertebrates that have evolved flight. As they comprise almost all insects, the species are too numerous to list here. Insect flight
Insects are the only group of invertebrates that have evolved wings and flight. Insects first flew in the Carboniferous, some 350 to 400 million years ago, making them the first animals to evolve flight. Wings may have evolved from appenda ...
is an active research field.
Birds
* Birds (flying, soaring) – Most of the approximately 10,000 living species can fly (flightless bird
Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species, including the well known ratites (ostriches, emu, cassowaries, rheas, and kiwi) and penguins. The smallest flightless bird is the ...
s are the exception). Bird flight is one of the most studied forms of aerial locomotion in animals. See List of soaring birds
This is a list of soaring birds, which are birds that 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.
;Bird of prey
* Buzzards
* ...
for birds that can soar as well as fly.
Mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...
* 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 ...
s. There are approximately 1,240 bat species, representing about 20% of all classified mammal species. Most bats are nocturnal and many feed on insects while flying at night, using echolocation to home in on their prey.
* Humans
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
. Humans are currently the only extant species known to be capable of flight by the use of tools like airplanes
An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectr ...
, helicopters
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...
, hot air balloons
A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries p ...
, and rigid airships like the Zeppelin
A Zeppelin is a type of rigid airship named after the German inventor Count Ferdinand von Zeppelin () who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874Eckener 1938, pp ...
, amongst many other examples.
Extinct
Pterosaurs
* Pterosaurs were the first flying vertebrates, and are generally agreed to have been sophisticated flyers. They had large wings formed by a patagium stretching from the torso to a dramatically lengthened fourth finger. There were hundreds of species, most of which are thought to have been intermittent flappers, and many soarers. The largest known flying animals are pterosaurs.
Non-avian dinosaurs
* Theropod
Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...
s (gliding and flying). There were several species of theropod dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
thought to be capable of gliding or flying, that are not classified as birds (though they are closely related). Some species (''Microraptor
''Microraptor'' (Greek, μικρός, ''mīkros'': "small"; Latin, ''raptor'': "one who seizes") is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They ...
gui'', ''Microraptor zhaoianus'', and ''Changyuraptor
''Changyuraptor '' is a genus of "four-winged", predatory dinosaurs. It is known from a single fossil specimen representing the species ''Changyuraptor yangi'', which was discovered from Early Cretaceous (125 million year old) deposits in Liaoni ...
'') have been found that were fully feathered on all four limbs, giving them four 'wings' that they are believed to have used for gliding or flying. A recent study indicates that flight may have been acquired independently in various different lineages though it may have only evolved in theropods of the Avialae
Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally use ...
.
Gliding animals
Extant
Insects
* Gliding bristletails. Directed aerial gliding descent is found in some tropical arboreal bristletails, an ancestrally wingless sister taxa to the winged insects. The bristletails median caudal filament is important for the glide ratio
In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficiency under giv ...
and gliding control
* 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. The flightless workers of these insects have secondarily gained some capacity to move through the air. Gliding has evolved independently in a number of arboreal ant species from the groups Cephalotini
Fungus-growing ants (tribe Attini) comprise all the known fungus-growing ant species participating in ant–fungus mutualism. They are known for cutting grasses and leaves, carrying them to their colonies' nests, and using them to grow fungus on ...
, Pseudomyrmecinae
Pseudomyrmecinae is a small subfamily of ants containing only three genera of slender, large-eyed arboreal ants, predominantly tropical or subtropical in distribution. In the course of adapting to arboreal conditions (unlike the predominantly ...
, and Formicinae
The Formicinae are a subfamily within the Formicidae containing ants of moderate evolutionary development.
Formicines retain some primitive features, such as the presence of cocoons around pupae, the presence of ocelli in workers, and little ...
(mostly '' Camponotus''). All arboreal dolichoderines and non-cephalotine myrmicine
Myrmicinae is a subfamily of ants, with about 140 extant genera; their distribution is cosmopolitan. The pupae lack cocoons. Some species retain a functional sting. The petioles of Myrmicinae consist of two nodes. The nests are permanent and ...
s except '' Daceton armigerum'' do not glide. Living in the rainforest canopy like many other gliders, gliding ants use their gliding to return to the trunk of the tree they live on should they fall or be knocked off a branch. Gliding was first discovered for '' Cephalotes atreus'' in the Peru
, image_flag = Flag of Peru.svg
, image_coat = Escudo nacional del Perú.svg
, other_symbol = Great Seal of the State
, other_symbol_type = National seal
, national_motto = "Firm and Happy f ...
vian rainforest. ''Cephalotes atreus'' can make 180 degree turns, and locate the trunk using visual cues, succeeding in landing 80% of the time. Unique among gliding animals, Cephalotini and Pseudomyrmecinae ants glide abdomen first, the Forminicae however glide in the more conventional head first manner.
* Gliding immature insects. The wingless immature stages of some insect species that have wings as adults may also show a capacity to glide. These include some species of cockroach
Cockroaches (or roaches) are a Paraphyly, paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are we ...
, mantis
Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate and tropical habitats. They ha ...
, katydid, stick insect and true bug
Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to around , ...
Spiders
* Ballooning (spider), Ballooning spiders (parachuting). The young of some species of spiders travel through the air by using silk draglines to catch the wind, as may some smaller species of adult spider, such as the money spider family. This behavior is commonly known as "ballooning". Ballooning (spider), Ballooning spiders make up part of the aeroplankton
Aeroplankton (or aerial plankton) are tiny lifeforms that float and drift in the air, carried by wind. Most of the living things that make up aeroplankton are very small to microscopic in size, and many can be difficult to identify because of ...
.
* Gliding spiders. Some species of arboreal spider of the genus ''Selenops'' can glide back to the trunk of a tree should they fall
Molluscs
* Flying squid. Several oceanic squids of the family Ommastrephidae, such as the Todarodes pacificus, Pacific flying squid, will leap out of the water to escape predators, an adaptation similar to that of flying fish. Smaller squids will fly in shoals, and have been observed to cover distances as long as . Small fins towards the back of the mantle do not produce much lift, but do 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 has been observed to glide for distances over , at speeds of up to .
Fish
* 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 d ...
. There are over 50 species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of flying fish belonging to the family (biology), family Exocoetidae. They are mostly marine (ocean), marine fishes of small to medium size. The largest flying fish can reach lengths of but most species measure less than in length. They can be divided into two-winged varieties and four-winged varieties. Before the fish leaves the water it increases its speed to around 30 body lengths per second and as it breaks the surface and is freed from the drag of the water it can be traveling at around .[Ross Piper, Piper, Ross (2007), ''Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals'', Greenwood Press (publisher), Greenwood Press.] The glides are usually up to in length, but some have been observed soaring for hundreds of metres using the updraft on the leading edges of waves. The fish can also make a series of glides, each time dipping the tail into the water to produce forward thrust. The longest recorded series of glides, with the fish only periodically dipping its tail in the water, was for 45 seconds (Video here). It has been suggested that the genus ''Exocoetus'' is on an evolutionary borderline between flight and gliding. It flaps its enlarged pectoral fins when airborne, but still seems only to glide, as there is no hint of a power stroke. It has been found that some flying fish can glide as effectively as some flying birds.
* Halfbeaks. A group related to the Exocoetidae, one or two hemirhamphid species possess enlarged pectoral fins and show true gliding flight rather than simple leaps. Marshall (1965) reports that ''Euleptorhamphus viridis'' can cover in two separate hops.
* Freshwater butterflyfish (possibly gliding). ''Pantodon buchholzi'' has the ability to jump and possibly glide a short distance. It can move through the air several times the length of its body. While it does this, the fish flaps its large pectoral fins, giving it its common name. However, it is debated whether the freshwater butterfly fish can truly glide, Saidel et al. (2004) argue that it cannot.
Amphibians
Gliding has evolved independently in two families of tree frogs, the Old World Rhacophoridae and the New World Hylidae. Within each lineage there are a range of gliding abilities from non-gliding, to parachuting, to full gliding.
* Rhacophoridae 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 ...
s. A number of the Rhacophoridae, such as Wallace's flying frog (''Rhacophorus nigropalmatus''), have adaptations for gliding, the main feature being enlarged toe membranes. For example, the Malayan flying frog ''Rhacophorus prominanus'' glides using the membranes between the toes of its limbs, and small membranes located at the heel, the base of the leg, and the forearm. Some of the frogs are quite accomplished gliders, for example, the Chinese flying frog ''Rhacophorus dennysi'' can maneuver in the air, making two kinds of turn, either flight dynamics, rolling into the turn (a banked turn) or flight dynamics, yawing into the turn (a crabbed turn).
* Hylidae 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 ...
s. The other frog family that contains gliders.
Reptiles
Several lizards and snakes are capable of gliding:
*
Draco lizard, ''Draco'' lizards. There are 28 species of lizard of the genus ''Draco lizard, Draco'', found in Sri Lanka, India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, and Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...
. They live in trees, feeding on tree ants, but nest on the forest floor. They can glide for up to and over this distance they lose only in height. Unusually, their patagium (gliding membrane) is supported on elongated ribs rather than the more common situation among gliding vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
s of having the patagium attached to the limbs. When extended, the ribs form a semicircle on either side the lizard's body and can be folded to the body like a folding fan.
* Holaspis, Gliding lacertids. There are two species of gliding lacertid, of the genus ''Holaspis'', found in Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. They have fringed toes and tail sides and can flatten their bodies for gliding or parachuting.
* Ptychozoon, ''Ptychozoon'' flying geckos. There are six species of gliding gecko, of the genus ''Ptychozoon'', from Southeast Asia. These lizards have small flaps of skin along their limbs, torso, tail, and head that catch the air and enable them to glide.
* Luperosaurus, ''Lupersaurus'' flying geckos. A possible sister-taxon to ''Ptychozoon'' which has similar flaps and folds and also glides.
* Thecadactylus, ''Thecadactylus'' flying geckos. At least some species of ''Thecadactylus'', such as ''T. rapicauda'', are known to glide.
* Cosymbotus, ''Cosymbotus'' flying gecko. Similar adaptations to ''Ptychozoon'' are found in the two species of the gecko genus ''Cosymbotus''.
* ''Chrysopelea'' snakes. Five species of snake from Southeast Asia, Melanesia, and India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. The paradise tree snake of southern Thailand, Malaysia, Borneo
Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and ea ...
, Philippines, and Sulawesi is the most capable glider of those snakes studied. It glides by stretching out its body sideways and opening its ribs so the belly is concave, and by making lateral slithering movements. It can remarkably glide up to and make 90 degree turns.
Mammals
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 ...
s are the only Bat flight, freely flying mammals. A few other mammals can glide or parachute; the best known are flying squirrels and Colugo, flying lemurs.
* Flying squirrels (subfamily Petauristinae). There are more than 40 living species divided between 14 genera of flying squirrel. Flying squirrels are found in Asia (most species), North America (genus ''Glaucomys'') and Europe (Siberian flying squirrel). They inhabit tropical, temperate, and Subarctic environments, with the ''Glaucomys'' preferring boreal and montane coniferous forests, specifically landing on red spruce (''Picea rubens'') trees as landing sites; they are known to rapidly climb trees, but take some time to locate a good landing spot. They tend to be nocturnal and are highly sensitive to light and noise. When a flying squirrel wishes to cross to a tree that is further away than the distance possible by jumping, it extends the cartilage spur on its elbow or wrist. This opens out the flap of furry skin (the patagium) that stretches from its wrist to its ankle. It glides spread-eagle and with its tail fluffed out like a parachute, and grips the tree with its claws when it lands. Flying squirrels have been reported to glide over .
* Anomalures or scaly-tailed flying squirrels (family Anomaluridae). These brightly coloured African rodents are not squirrels but have evolved to a resemble flying squirrels by convergent evolution. There are seven species, divided in three genera. All but one species have gliding membranes between their front and hind legs. The genus ''Idiurus'' contains two particularly small species known as flying mice, but similarly they are not true mice.
* Colugos or "flying lemurs" (order Dermoptera). There are two species of colugo. Despite their common name, colugos are not lemurs; true lemurs are primates. Molecular evidence suggests that colugos are a sister group to primates; however, some mammalogists suggest they are a sister group to 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 ...
s. Found in Southeast Asia, the colugo is probably the mammal most adapted for gliding, with a patagium that is as large as geometrically possible. They can glide as far as with minimal loss of height. They have the most developed propatagium out of any gliding mammal with a mean launch velocity of approximately 3.7 m/s; the Mayan Colugo has been known to initiate glides without jumping.
* Sifaka, a type of lemur, and possibly some other primates (possible limited gliding or parachuting). A number of primates have been suggested to have adaptations that allow limited gliding or parachuting: sifakas, indris, galagos and saki monkeys. Most notably, the sifaka, a type of lemur, has thick hairs on its forearms that have been argued to provide drag, and a small membrane under its arms that has been suggested to provide lift by having aerofoil properties.[Darren Naish: Tetrapod Zoology: Literally, flying lemurs (and not dermopterans)](_blank)
/ref>
* Flying phalangers or wrist-winged gliders (subfamily Petaurinae). Possums found in Australia, and New Guinea. The Patagium, gliding membranes are hardly noticeable until they jump. On jumping, the animal extends all four legs and stretches the loose folds of skin. The subfamily contains seven species. Of the six species in the genus ''Petaurus'', the sugar glider and the Biak glider are the most common species. The lone species in the genus ''Gymnobelideus'', Leadbeater's possum has only a vestigial gliding membrane.
* Petauroides volans, Greater glider (''Petauroides volans''). The only species of the genus ''Petauroides'' of the family Pseudocheiridae. This marsupial is found in Australia, and was originally classed with the flying phalangers, but is now recognised as separate. Its flying membrane only extends to the elbow, rather than to the wrist as in Petaurinae. It has elongated limbs compared to its non-gliding relatives.
* Acrobatidae, Feather-tailed possums (family Acrobatidae). This family of marsupials contains two genera, each with one species. The feathertail glider (''Acrobates pygmaeus''), found in Australia is the size of a very small mouse and is the smallest mammalian glider. The feathertail possum (''Distoechurus pennatus'') is found in New Guinea, but does not glide. Both species have a stiff-haired feather-like tail.
Extinct
Reptiles
*
Extinct reptiles similar to ''Draco''. There are a number of unrelated extinct lizard-like reptiles with similar "wings" to the ''Draco ''lizards. These include the Late Permian Weigeltisauridae, the Triassic Kuehneosauridae and ''Mecistotrachelos'', and the Cretaceous lizard ''Xianglong''. The largest of these, ''Kuehneosaurus'', has a wingspan of , and was estimated to be able to glide about .
* Sharovipterygidae. These strange reptiles from the Upper Triassic of Kyrgyzstan and Poland unusually had a membrane on their elongated hind limbs, extending their otherwise normal, flying-squirrel-like patagia significantly. The forelimbs are in contrast much smaller.
*
* ''Hypuronector''. This bizarre drepanosaur displays limb proportions, particularly the elongated forelimbs, that are consistent with a flying or gliding animal with patagia.
Non-avian dinosaurs
*
Scansoriopterygidae is unique among dinosaurs for the development of membranous wings, unlike the feathered airfoils of other theropods. Much like modern anomalures it developed a bony rod to help support the wing, albeit on the wrist and not the elbow.
Fish
* Thoracopteridae is a lineage of Triassic flying fish-like Perleidiformes, having converted their pectoral and pelvic fins into broad wings very similar to those of their modern counterparts. The Ladinian genus ''Potanichthys'' is the oldest member of this clade, suggesting that these fish began exploring aerial niches soon after the Permian-Triassic extinction event.
Mammals
* ''Volaticotherium antiquum''. A gliding eutriconodont, long considered the earliest gliding mammal until the discovery of contemporary gliding haramiyidans. It lived around 164 million years ago and used a fur-covered skin membrane to glide through the air. The closely related ''Argentoconodon'' is also thought to have been able to glide, based on postcranial similarities; it lived around 165 million years ago, during the Middle-Late Jurassic of what is now China
* The haramiyidans ''Vilevolodon'', ''Xianshou'', ''Maiopatagium'' and ''Arboroharamiya'' known from the Middle-Late Jurassic of China had extensive patagia, highly convergent with those of colugos.
*A gliding metatherian (possibly a marsupial) is known from the Paleocene of Itaboraí, Brazil.
*A gliding rodent belonging to the extinct family Eomyidae, ''Eomys quercyi'' is known from the late Oligocene of Germany.
See also
*Animal locomotion
*Flying mythological creatures
*Insect thermoregulation
*Organisms at high altitude
References
Further reading
*
*
*
*
*
*
*
* The Pterosaurs: From Deep Time by David Unwin
External links
Canopy Locomotion
from Mongabay online magazine
Learn the Secrets of Flight
from Vertebrate Flight Exhibit at University of California Museum of Paleontology, UCMP
Canopy life
Insect flight, photographs of flying insects
– Rolf Nagels
Map of Life - "Gliding mammals"
– University of Cambridge
{{DEFAULTSORT:Flying And Gliding Animals
Animal flight,
Ethology
Evolution of animals
Natural history
Gliding animals,