Storrs Olson, Curator of Birds at the Smithsonian National Museum of Natural History, lambasted the community of scientists and journalists investigating the connection between theropod dinosaurs and birds in an open letter he sent to the head of National Geographic's Committee for Research and Development, Peter Raven, on November 1, 1999. In that letter, he said:

"The idea of feathered dinosaurs and the theropod origin of birds is being actively promulgated by a cadre of zealous scientists acting in concert with certain editors at Nature and National Geographic who themselves have become outspoken and highly biased proselytizers of the faith. Truth and careful scientific weighing of evidence have been among the first casualties in their program, which is now fast becoming one of the grander scientific hoaxes of our age—the paleontological equivalent of cold fusion."

With a paper on a new ceratosaur from Xinjiang by National Geographic grantees Xu Xing and James Clark published today in Nature, yet another test of the hypothesis that birds had theropod origins has been presented. And, once again, the hypothesis passed.

In layman's terms, here are the major objections to the dinosaur-bird hypothesis that have been listed over the years by opponents of the idea:

1) The supposed dinosaur relatives of birds appear millions of years after the earliest known bird, Archaeopteryx.

Comment: A number of maniraptors, including dromaeosaurs, which have been proposed as a possible sister group of birds, now predate Archaeopteryx.

2) Dinosaurs were not small enough to evolve into birds.

Comment: We now have bird-sized dinosaurs, such as Microraptor and Meilong.

3) The feathers on dinosaurs aren't feathers.

Comment: One would have to be blind to not acknowledge that dinosaurs had feathers. A work-around for some objectors has been to suggest that the feathered dinosaurs are secondarily flightless birds.

4) There are no feathers that predate Archaeopteryx.

Comment: Both Pedopenna and Epidexipteryx hui are feathered dinosaurs known from geological formations that, at 152 to 168 million years old (ages still being nailed down), are slightly older than Archaeopteryx.

  
The diagram above shows how the arrangement of digits in Limusaurus is consistent with that of birds, and suggests a solution to the finger dilemma. The photograph shows Limusaurus's curious finger arrangement, where the second digit has become enlarged.
Photo © James M. Clark.

Finally,

5) Bird wings evolved from the 2nd, 3rd, and 4th digits while theropod dinosaur hands evolved from the 1st, 2nd, and 3rd. The evolutionary transition from dinosaurs to birds, therefore, is not the simplest explanation, since dinosaurs would have had to lose their first digit and regrow the 4th.

Comment: As Xu and Clark's paper shows, it is possible that what scientists thought was the 1st digit in theropod hands was really an enlarged 2nd digit.

In some ways the finger dilemma was the last unanswered objection, a last pin standing, even though other evidence has been bowled at it before. Something tells me this pin isn't going down easily and objections to the bird-dinosaur hypothesis have not ended, despite the fact that test after test has supported the hypothesis. If Nature and National Geographic editors are outspoken and highly biased proselytizers of a faith as Storrs Olson says, perhaps that faith is in the scientific process. Hypotheses can be tested. Hyperbole becomes obvious over time.

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