There are a number of insects and other animals that are capable of flying backwards or reversing direction while in flight. This ability allows them to maneuver quickly and evade predators or threats. Flying backwards requires specialized anatomical features and wing motions to generate backward thrust. The distance an animal can fly backwards depends on the species, but some can manage several body lengths.
Insects That Can Fly Backwards
Dragonflies
Dragonflies are adept fliers that can propel themselves backwards with ease. Their four wings allow for complex changes in wing angle and position to produce reverse thrust. Dragonflies rely on this quick backward flight to capture prey and evade predators during aerial dogfights. They are capable of backward bursts of up to 3 meters.
Butterflies
Many butterflies can fly backwards for short distances. Fritillary butterflies in particular are known for their ability to rapidly fly backwards when threatened. Their backwards flight is typically less than 50 centimeters. It provides them an escape option from predators and serves as part of their evasive defensive posturing.
Moths
Like butterflies, some moths are able to fly backwards. Luna moths and hawk moths have both been observed exhibiting reverse flight. When taking off from a flower or plant, they will occasionally back away first before turning around to fly forward. Their backward flights appear clumsy and limited to a couple body lengths.
Flies
Flies are incredibly acrobatic fliers capable of hovering, spinning, and flying backwards with ease. They reverse direction by altering the angle of their wings to generate backward aerodynamic forces. Small fruit flies can fly backwards up to 30 body lengths, an impressive feat considering their tiny size. Larger horse flies and deer flies may not be as maneuverable but can still fly backwards a few inches.
Insect | Backward Flight Distance |
---|---|
Dragonfly | Up to 3 meters |
Butterfly | Less than 50 centimeters |
Moth | A couple body lengths |
Fruit fly | Up to 30 body lengths |
Birds That Can Fly Backwards
While less common in birds, some species are capable of backwards flight. They primarily use this ability to maneuver in confined spaces where forward flight is difficult.
Hummingbirds
Hummingbirds are amazing flyers that can hover, fly sideways, backwards, and even upside down. They sometimes use backward hovering or flight to retreat from flower openings or feeders. Their backward flight is typically limited to a few body lengths given the high energy required to fly in reverse.
Kingfishers
Kingfishers frequently fly backwards from branches or perches to retreat into cavities and nests. They beat their wings extremely quickly, allowing them to generate the backwards thrust needed to maneuver into tight space openings. Kingfishers may fly backwards up to a meter in this manner.
Bird | Backward Flight Distance |
---|---|
Hummingbird | A few body lengths |
Kingfisher | Up to 1 meter |
Other Backwards Flying Animals
Bats
Bats are impressively agile fliers, with some species able to fly backwards. They mainly use this ability when exiting confined spaces like caves or hollows. Some bats can fly backwards up to 3 meters to retreat back into openings. Their backwards thrust is generated through wing movements and articulated tail membranes.
Flying Squirrels
Flying squirrels are actually gliders, using flaps of skin between their limbs to glide between trees. However, before takeoff they are capable of scurrying backwards along a branch for up to a meter. This gives them room to spread their limbs and launch into a glide.
Flying Fish
Flying fish don’t actually fly, but propel themselves out of the water using enlarged pectoral fins. On occasion, they can angle these fins to provide backwards thrust to retreat from predators. Their backwards ‘flights’ are brief and may span a couple meters.
Animal | Backward Flight Distance |
---|---|
Bat | Up to 3 meters |
Flying squirrel | Up to 1 meter scurrying |
Flying fish | A couple meters gliding |
Insect Backward Flight Mechanics
Insects accomplish backward flight through specialized wing aerodynamics and kinematics. Symmetrical and asynchronous wing flapping allows generation of reverse thrust.
Symmetrical Wing Strokes
Normal forward insect flight relies on asymmetric wing strokes to produce thrust. The downstroke generates more lift than the upstroke. Backward flight requires symmetrical wing strokes where both halves of the flapping cycle contribute equal lift and thrust generation.
Asynchronous Wing Movement
Insects also utilize asynchronous wing movement, where the front and hind wings flap at different phases. By altering the timing and angles, this can result in forward or backward aerodynamic forces. Small adjustments lead to remarkable maneuverability.
Leading Edge Vortices
At high angles of attack, insects can create leading edge vortices above their wings to provide lift. Varying the direction of these vortices allows generation of forward or backward thrust. Dragonflies likely rely on this mechanism for their powerful backwards flight.
Lift Distribution
Careful control over where lift is produced along the wing also assists backward flight. Generating more lift at the rear while reducing lift at the front of the flapping wings results in a rearward push.
Bird Backward Flight Mechanics
Birds that exhibit reverse flight utilize high wingbeat frequencies and tail maneuvers.
High Frequency Flapping
Rapid wing flapping is required to produce sufficient backward thrust. Hummingbirds beat their wings up to 80 times per second in normal forward flight. Even higher frequencies are needed for their brief backward bursts.
Tail Spreading
Birds may fan or spread their tails to increase drag at the rear of their body. This counteracts the forward thrust produced by the wings flapping backwards, assisting in rearward movement.
Tail Wagging
Lateral motions of the fanned tail can produce asymmetric drag that turns the backward thrust into a specific direction. This allows the birds to have controlled maneuverability while flying in reverse.
Conclusion
While uncommon, the ability to fly backwards is an impressive adaptation in certain groups of flying animals. Small insects like flies and dragonflies are able to generate sufficient backward thrust to reverse direction rapidly, thanks to specialized wing aerodynamics. Birds like hummingbirds can briefly fly backwards by flapping their wings at extremely high frequencies. Other gliding animals may also exhibit limited rearward movement. This unique mode of flight allows these creatures to maneuver in confined spaces and evade threats with ease. Next time you see a fly or hummingbird, take a close look to see if you can observe their amazing backward flying skills!