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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Flying and gliding animals | 1/8 | https://en.wikipedia.org/wiki/Flying_and_gliding_animals | reference | science, encyclopedia | 2026-05-05T03:46:37.316378+00:00 | kb-cron |
A number of animals are capable of aerial locomotion, either by active flight, by passive gliding or, in rare occasions, by kiting/ballooning. Such animals typically have appendages that interact with air to generate lift in order to overcome the weight of their own body and any payload they are carrying (e.g. food/prey, nesting materials). Majority of flying and glide animals are terrestrial, while species from one extant taxon, i.e. the flying fish, are aquatic. The ability to fly or glide has appeared via convergent evolution many times throughout the history of life, and has evolved prominently in at least four terrestrial clades: insects, pterosaurs, birds and bats. Gliding and kiting, which are essentially controlled, prolonged free falls, have evolved on many more occasions, especially among arboreal species. Usually the aerial trait is to aid animals leaping directly across extended distances from one tree canopy to another without having to descend to the ground, which will otherwise expose them to risks from ground predators, although there are other reasons why aerial locomotions have developed. Gliding, in particular, has evolved among forest animals, especially in the rainforests in Asia (most especially Borneo) where the trees are tall (making it costly to descend and travel between trees) and groundcovers are dense (thus favoring ambush predators). Several species of amphibians (e.g. flying frogs) and reptiles (e.g. flying lizards and flying snakes) have also evolved gliding ability, typically as a means of escape behavior to evade predators, while kiting/ballooning (which resembles paragliding or kitesurfing) has developed among several species of silk-spinning invertebrates such as spiders, spider mites and some caterpillars as a means of airborne dispersal.
== 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.
=== Unpowered === These modes of locomotion typically require an animal start from a raised location, converting that potential energy into kinetic energy 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: decreasing altitude under the force of gravity, using no adaptations to increase drag or provide lift. 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. Some gliding animals may use their gliding membranes for drag rather than lift, to safely descend. Gliding flight: falling at an angle less than 45° from the horizontal with lift from adapted aerofoil 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 has evolved at least four times: first in the insects, then in pterosaurs, next in birds, and last in bats. Studies on theropod dinosaurs do suggest multiple (at least 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, 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: being carried up into the air from the aerodynamic effect on long strands of silk in the wind. Certain silk-producing arthropods, mostly small or young spiders, secrete a special light-weight gossamer silk for ballooning, sometimes traveling great distances at high altitude. Soaring: 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, 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 ==