Most people are not ordinarily concerned with birds. I must admit that I don't give them much thought. But, I have always been enthralled by dinosaurs; resurrected skeletal frames at the museum; boyhood dreams of fern forests and primordial landscapes; and giant creatures that ran across swamps, swam in the oceans and soared in the skies for 140 million years.

And every dinosaur fan knows about Archaeopteryx, a primitive bird-like animal that, when excavated shortly after the publication of Darwin's Origin of Species in 1860, seemed to confirm both evolution itself and the notion that birds and certain dinosaurs are closely linked. Steven Spielberg more than suggested the connection in his movie Jurassic Park, which offered the cladographic or phylogenic descent as proven science. So, after this little introduction, you might appropriately conclude that I am interested in birds, at least insofar as they are related to dinosaurs.

But, last week, a New York Times article by John Noble Winford threw my gestalt view on the subject into a tizzy and got me thinking a good deal about avians. Apparently, scientists now believe that Archaeopteryx "grew at a rate faster than living reptiles but only one-third as fast as that of modern birds...evidence, [that] challenges the hypothesis that Archaeopteryx had already developed characteristics of a physiologically modern bird."

Additionally, and in important part, it said that "under a polarizing microscope, the dense microstructure of the [remaining] bone showed few traces of blood vessels...evidence of a slow metabolism by which the individual probably took more than two years to reach adult size. Birds have especially fast metabolisms, making them able to leave the nest in days or a few weeks."

In other words, unlike modern birds, Archaeopteryx physiology was slow, inefficient and probably ectothermic or cold blooded, like that of dinosaurs.

What? I had always imagined that dinos were actually warm blooded like us, and I still have reason to believe that they were. Let's examine the following:

1) Their size must have required an awful lot of eating (hunting or grazing); activity that would have necessitated warm blooded efficiency. 2) A cold blooded condition would have meant that they needed to warm themselves in the sun to reach an "active state." How long would a 10 or 20 ton animal with a huge surface area need to sit before becoming active? 3) The size of many dinosaurs and the length of their blood vessels, especially those with long necks like Diplodocus or Brachiasaurus, suggests a heavy column of fluid that would have required significant hydrostatic pressure to pump.

In my opinion, these facts and scenarios still argue in favor of endothermic dinosaur physiology, but where does that leave our fine, feathered friend, Archaeopteryx? Well, perhaps on an evolutionary lineage that, somewhere in the remote past, diverged from both dinosaurs and birds. Perhaps it leaves Archaeopteryx out on a limb that projected over the abyss of extinction. Either way, I think we can still safely embrace childhood preconceptions.

For the moment, revisionism is for the birds.

Excerpts from JOHN NOBLE WILFORD

The New York Times - October 8, 2009