Like its close relative
Cryptovolans (possibly a junior synonym of
Microraptor),
Microraptor had two sets of wings, on both its fore- and hind legs (close studies of the Berlin specimen of the primitive bird
Archaeopteryx show that it too, had flight feathers on its hind legs, albeit shortened). The long feathers on the legs of
Microraptor were true flight feathers as seen in modern
birds, with asymetrical vanes on the arm, leg, and tail feathers. As in bird wings,
Microraptor had both primary (anchored to the hand) and secondary (anchored to the arm) flight feathers. This standard wing pattern was mirrored on the hind legs, with flight feathers anchored to the upper foot bones as well as the upper and lower leg. It had been proposed by Chinese scientists that the animal glided, and probably lived in trees, pointing to the fact that wings anchored to the feet of
Microraptor would have hindered their ability to run on the ground, and suggest that all primitive dromaeosaurids may have been arboreal.
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Sankar Chatterjee determined in 2005 that, in order for the creature to glide or fly, the wings must have been split-level (like a
biplane) and not overlayed (like a
dragonfly), and that the latter posture would have been anatomically impossible. Using this biplane model, Chatterjee was able to calculate possible methods of gliding, and determined that
Microraptor most likely employed a
phugoid style of gliding--launching itself from a perch, the animal would have swooped downward in a deep 'U' shaped curve and then lifted again to land on another tree. The feathers not directly employed in the biplane wing structure, like those on the tibia and the tail, could have been used to control drag and alter the flight path, trajectory, etc. The orientation of the hind wings would also have helped the animal control its gliding flight. Chatterjee also used computer algorithms that test animal flight capacity to test whether or not
Microraptor was capable of true, powered flight, in addition to passive gliding. The resulting data showed that
Microraptor did have the requirements to sustain level powered flight, so it is theoretically possible that the animal flew on occasion in addition to gliding.
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