Actually relatively few modern pterosaurs grow to become as large as the largest of those flying creatures known from fossils. At least some species probably continue to grow as long as they live, making the giant ones rare, for many things can cause an organism to die; remember the greatest risk one faces in old age: death. Statistics make it clear that pterosaur sightings, at least the more credible reports, show a steady range of wingspan estimates, with a slight drop off in the flying creatures appearing to have a wingspan greater than about thirty feet. Let’s examine that idea first.
Why do so many sightings involve giant pterosaurs?
That’s a better question, for the giant ones are indeed rare. What do I mean? Put yourself in the following situation, and let’s say that you are unaware of reports of living pterosaurs. Walk out your front door to your car as something flies over your house. Whatever that something is, let us say it’s over a hundred feet high and between the size of a sparrow and a crow. Would you look up to see what kind of bird it is? Why bother?
Now keep everything the same except the size: The flying creature has a wingspan of twenty feet. Even at 150 feet above your house, it could very well catch the corner of your eye and perhaps change your life, as you turn your head. Our subconscious has a way of telling us when something is odd.
The point? Modern pterosaurs with wingspans greater than large birds catch the attention of eyewitnesses, even though those larger ones are nocturnal and relatively rare. When one of them takes off into the air in daylight, for whatever reason, how easy we can take notice! That shocking appearance might also increase an eyewitness’s desire to report the sighting to me, increasing the number of giant flying creatures in my reports.
If we could take a census of all modern pterosaurs, of all species now living, I would not be shocked to learn that less than 1% of them have wingspans over twenty feet. Take that in the context of the late-2012 analysis of the 128 most credible sighting reports: Of those estimating wingspans, 26% of the estimates were over twenty feet. But I would guess the actual number of animals (of that size) at much closer to 1% of the total population.
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Pterosaur Sightings and Photos
Direct eyewitness testimony of a pterosaur sighting is essential, even if we have to wait many years for photographic evidence.
Was it a Giant Prehistoric Bird?
. . . why is that word used by some eyewitnesses: “bird?” That word comes to mind because birds commonly fly overhead, during the daylight when we notice things in the sky, far more commonly than we notice bats.
What can we conclude from the evenness of the data on wingspan estimates? No significant number of hoaxes were involved, for expectations regarding pterosaur size would have made one or two peaks; there is no significant peak anywhere that would suggest such a thing.