Having 4 wings is very rare in the animal kingdom. Most flying animals like birds, bats, and insects have 2 wings. However, there are a few exceptions where animals have evolved to have 4 wings.
Insects with 4 wings
The most common animals with 4 wings are certain insects. All insects have 6 legs, but some insects have 2 pairs of wings instead of just 1 pair. Dragonflies, mayflies, caddisflies, stoneflies, dobsonflies, and alderflies all have 4 wings as adults. Their wings are arranged with the forewings being larger and the hindwings being smaller. The forewings and hindwings on each side are controlled by separate muscles, allowing these insects great maneuverability and control in flight.
Here are some examples of insects with 4 wings:
Insect | Image |
---|---|
Dragonfly | |
Mayfly | |
Caddisfly |
Dragonflies are probably the most well-known 4-winged insects. There are over 5,000 species of dragonflies found on every continent except Antarctica. Dragonflies are extremely adept fliers, capable of sudden stops, turns, and reversals.
Why do some insects have 4 wings?
Insects evolved from ancient arthropods that had multiple pairs of legs. Over time, some of these leg-like appendages evolved into wings. Having 4 wings provides insects with exceptional flight control and maneuverability compared to just 2 wings. The forewings and hindwings can operate independently, allowing for precision hovering, darting motions, and sudden flight pattern changes. Having 4 wings also provides redundancy – if one wing is damaged, the insect can still fly with the other 3.
Pterosaurs
Pterosaurs were flying reptiles that lived during the age of dinosaurs. They are frequently referred to as “pterodactyls” though Pterodactylus is just one genus of pterosaur. Pterosaurs had wings formed by membranes of skin that stretched from an elongated fourth finger to their body. Unlike birds and bats, pterosaurs had four wings – a large forewing and smaller hindwing on each side of their body.
Here are some examples of pterosaurs:
Pterosaur | Image |
---|---|
Pterodactylus | |
Pteranodon | |
Quetzalcoatlus |
The earliest pterosaurs from the late Triassic period had smaller hindwings but by the Jurassic and Cretaceous periods most pterosaurs had large forewings and hindwings of similar size. The hindwings provided added lift and control in flight. Some pterosaurs had wingspans over 30 feet wide!
Pterosaur flight
Unlike birds, pterosaurs had no feathers. Their wings were formed by skin and muscle over an elongated fourth finger. Scientists were uncertain how pterosaurs flew with just a membrane wing, but research shows their wing membrane contained muscle fibers that could change the wing’s shape while flying. This allowed fine maneuvering similar to modern bats. The large forewings generated most of the thrust and lift needed for flight while the smaller hindwings provided additional lift and helped with turning.
Microraptor
Microraptor is the only known non-avian dinosaur that had four wings. It was a small feathered dinosaur that lived 120 million years ago in what is now China. Microraptor was about the size of a crow and had long feathers on both its forelimbs and hindlimbs. The leg feathers were asymmetrical like modern bird wings and allowed Microraptor to fly or glide.
Here is a model of Microraptor showing its 4 wings:
Microraptor likely spent time in trees and would use its four wings to help it glide from branch to branch. The leg wings provided lift and stability in the air. By changing the position and shape of the leg wings, Microraptor could steer and maneuver similar to modern raptors. Even without powered flight like birds, Microraptor’s four wings allowed exceptional aerial mobility.
The evolution of flight
Microraptor gives clues into how flight may have first evolved from dinosaurs. Front-winged flight likely started with small, feathered dinosaurs using their arm feathers for gliding assistance. Then leg feathers evolved to provide additional lift and control, leading to 4-winged gliding as seen in Microraptor. Eventually front-wing powered flight evolved into what we see in today’s birds. But for a brief period, some dinosaurs experimented with 4-winged flight on their way to conquering the skies.
Why don’t more modern animals have 4 wings?
While a few prehistoric reptiles evolved 4 wings, no modern vertebrates retained this adaptation. As birds evolved powered flight, their hindwings became smaller and eventually disappeared. Birds today have only their forelimbs modified into wings. For powered flight, two large wings prove more efficient than 4 smaller wings. Though insects managed to retain 4-winged flight.
Other animals may have found 4 wings unnecessary or even detrimental:
- Extra wings require more muscles and energy to fly.
- Four wings add aerodynamic drag and weight.
- Two large wings generate better lift than 4 smaller wings.
- Four wings makes movement on land more difficult.
For most animals, the ideal balance seems to be 2 wings – large enough for efficient flight but not too cumbersome for life on land. Of course evolution is unpredictable, so perhaps some future animal will surprise us by taking to the skies with 4 wings once again!
Conclusion
While 4-winged animals are rare today, they evolved several times independently in the past. Insects managed to retain 4 wings which provide exceptional flight agility and control. Pterosaurs and Microraptor also had front and hind wings for added lift and maneuverability in flight. But for most vertebrates, 2 larger wings ultimately proved more effective and efficient for powered flight. Of course nature has a habit of defying expectations, so a future 4-winged vertebrate can’t be ruled out entirely. For now, dragonflies remain the masters of the four-winged skies.