Paragraph 1: It is not known whether Archaeopteryx, the earliest birdlike creature for which fossils have been found, could fly—but it probably did, at least for short distances. We can make reasoned guesses about how it might have done so, but there is no conclusive evidence about flying in Archaeopteryx because while fossils can tell us about an animal’s physiology, they cannot tell us about an animal’s behavior. First, we should look at the methods that animals other than birds use to become airborne. Even though birds have the most astounding abilities of flight, they are not the only creatures to take to the air. Some existing species of frogs, snakes, lizards, and mammals launch themselves from a height and glide for considerable distances in the air. They do so by using skin flaps on the sides of their bodies or by extending broad, sail like limbs. The gliders of Australia are typical examples of this kind of flight. Some of the ancient reptiles living in the late Triassic period more than 200 million years ago used this method of flying. A fossil record of a flying reptile (a saurian) called Protoavis texensis has been dated to that time. That species could represent one of the first steps toward the evolution of birds, but many ancient reptiles had flaps of skin or long scale-like structures that they could have used for gliding or even more sustained flying.
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