Footnotes on alleged human footprints.

Footnotes on alleged human footprints

The Taylor trackway near the Paluxy River in Texas has been an important toehold for creationists trying to prove that the earth - which they believe was inhabited all at once by humans, dinosaurs and all other creatures that have ever lived on the planet - was created only several thousand years ago. For decades they have argued that oblong depressions in the trackway were made by humans at about the same time a dinosaur left its characteristic three-toed prints in the mud.

Earlier this year, John D. Morris at the Institute for Creation Research in Santee, Calif., backed down on this interpretation after amateur paleontologist Glen Kuban of North Royalton, Ohio, noticed that blue-gray toeprints have emerged next to the oblong depressions in the otherwise tan rocks. Kuban and others suspect that the toeprints appeared because natural processes had long ago filled them in with sediments that differ chemically from the surrounding rocks, and that they are changing color now because the river level has fallen in the last several years, exposing them to air.

In his June 19 letter to NATURE, Morris says the appearance of the toe stains suggests that "an unprecedented geological phenomenon has taken place...." But responding in the Oct. 2 NATURE, palentologist James O. Farlow of Indiana University-Purdue University at Ft. Wayne notes that similar "color distinctions" in dinosaur tracks have been found at two Colorado sites. Moreover, Farlow reports that the step angle and the relationship between foot size and stride in the oblong tracks reflect those of hundreds of other dinosaur trails he and others have studied. So, he says, "the color distinction is just icing on the cake."

Kuban has explained the oblong shape of the Taylor tracks by suggesting that the dinosaurs, which normally walked on their toes, had been putting the entire soles of their feet down as they walked. Farlow thinks this is a reasonable idea and notes in his NATURE letter that "flat-footed" dinosaur prints, while not common, have been found elsewhere. The mystery, he says, is why some dinosaurs chose to walk that way.

Will creationists now turn on their heels? One problem with the trackway issue, says Farlow, is that most creationists haven't studied enough tracks to see that there is a whole spectrum to the quality and shapes of dinosaur prints. "None know anything about dinosaur foot anatomy or have done detailed studies of tracks," he says. "So it's not surprising that they have made these kinds of errors."