"Dinosaur" petroglyphs at Kachina Bridge site, Natural Bridges National Monument, southeastern Utah: not dinosaurs after all
Among the many images made by prehistoric people on the walls of Kachina Bridge is what appears to be an unambiguous depiction of a sauropod dinosaur, herein called Dinosaur 1. Because mainstream science has produced no alternate explanation for Dinosaur 1, it has become an important weapon in the arsenal of the anti-evolution movement. The movement's proponents claim that it demonstrates the coexistence of humans and dinosaurs, thus casting doubt on the geological time scale of millions of years. Until now that claim has gone unchallenged. The hypothesis that a given petroglyph depicts a dinosaur predicts that the image is not a composite; depicts an animal; has features that cannot be reconciled with non-dinosaurian local fauna; has features of a specific, identifiable dinosaur; and is entirely human-made. These predictions were tested for Dinosaur 1 and three other alleged dinosaur petroglyphs at Kachina Bridge by on-site visual examination under varying light conditions. Examination reveals that the "neck" and "back" of Dinosaur 1 are a composite of two separate petroglyphs, and its "legs" are a natural mud or mineral stain. A second alleged sauropod petroglyph is a mere mud stain. The other two alleged dinosaur petroglyphs are human-made, but neither depicts an animal. The four Kachina Bridge "dinosaurs" are illusions produced by pareidolia. None of them satisfy the predictions of the hypothesis that a dinosaur is depicted. Dinosaur 1—heretofore a creationist poster child—and its counterparts now join the plethora of discredited "evidence" for the ancient coexistence of humans and dinosaurs.
KEY WORDS: petroglyph; Kachina Bridge; Sauropoda; creationism; young-earth
PE Article Number: 14.1.2A
Copyright: Palaeontological Association March 2011
Submission: 15 March 2010. Acceptance: 30 September 2010