Monday, March 5, 2012

Why a Hoax Fails

Why does a combination of hoaxes fail to explain the many sighting reports that have come up since the 1990's? Several things practically eliminate a hoaxes as an overall explanation for pterosaur sightings. Consider the data compiled from ninety-eight sightings, the more credible reports of apparent pterosaurs that I have encountered over the past eight years.

Wingspan Estimates
When we look at the wingspan estimates (58% of the sighting reports include it), we see
no dramatic peek above any valley, as we would expect from any major hoax-involvement:

2, 2, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 12, 12, 12.5,
13, 13, 13, 13, 15, 16, 16, 17, 17, 17, 18, 20, 20, 20, 20, 21, 21.5, 22, 24, 25, 25, 27,
29, 30, 30, 33, 33, 35, 40, 46

The five-number summary is: 2, 7.5, 13, 21.25, 46
Using Grubbs' test, there are no outliers here: a natural set of data.

Regarding hoax potential, perhaps the most obvious refutation of a combination of practical jokes is this: American hoaxers would most likely emphasize very large wingspan, to avoid any possibility of suggestions of misidentification of a large bird. But the data shows many estimates within the range of medium-to-large bird wingspans.

What about tail-length in relation to wingspan? Many sightings include descriptions of long tails that suggest Rhamphorhynchoid pterosaurs, and those long-tailed species are believed to have been much smaller, according to fossil records. But the estimates shown above, for wingspan, show nothing even remotely like any peak related to those fossils. Someone making a hoax on the basis of known sizes of those fossils would (when reporting a long tail) give a wingspan estimate less than about seven feet. The data shows something very different: Most estimates over seven feet. There was no major hoax involvement.

The data on wingspan estimates is consistant with what we would expect from the following combination of conditions:
  1. Eyewitnesses had various capabilities in giving size estimates
  2. A number of species of pterosaurs were observed
  3. A number of ages of pterosaurs were observed (different sizes)
  4. Sightings were under various conditions
  5. Very few (if any) hoaxes were involved
Much could be said about the degree of certainty of lack of feathers; I'll summarize: For those who gave some indication of how certain they were about lack of feathers, most admitted that they were not sure about no-feathers, and that is not at all what we would expect for data contaminated with any significant number of hoaxes: Hoaxers would report a certainty of featherless appearance. The actual data shows the opposite: More eyewitnesses report probably-no-feathers than those who report definitely-no-feathers.

Skeptics are probably unaware that the sightings that I have publicized over the years have been the more-credible accounts, NOT the more-incredible ones. In general, when a report suggests something may be wrong with the eyewitness, I keep it on file for reference, but I do not publicize it. Probable-hoaxes were kept out, and are not among the ninety-eight reports that have been analyzed.

All of that, however, is not to say that not one of those ninety-eight reports was a hoax: only that there could not have been many hoaxes, far less than 20% maximum, and that would be stretching it. In the end, for at least one species of pterosaur to still be living, it only takes one of those many sightings to have been valid, to prove modern living pterosaurs.

Pterosaur Sightings From Hoaxes?

I have been interviewing eyewitnesses for eight years now, ordinary persons who encountered extraordinary flying creatures: apparent pterosaurs. For the most part, these eyewitnesses seem to be credible, with no apparent reason to play a hoax.

Tunnel Pterodactyl of 1856

Much has been made of the obvious signs that this was only a hoax; I agree, it looks like a hoax. But some critics of living-pterosaur investigations have tried to use that to dispute eyewitness sightings in the 20th and 21st Centuries. How shabby that reasoning! 

No Hoax With Pterosaur Sightings
Evelyn Cheesman was a biologist who searched for insects and small animals in remote areas, including New Guinea, in the 1920′s and 1930′s. . . . Nobody suggests Cheesman ever played a hoax.

Hoax or Pterosaur?
. . . the experiences of the U. S. Marine Eskin C. Kuhn, whose sighting has been called a ”hoax.” I gave him a surprise phone call, a few years ago, and found him to be highly credible, answering my questions as a valid eyewitness would respond, not as a hoaxer would respond. He has stood by his sighting account for four decades, in spite of accusations that his experience never happened.