About 65.5 million years ago, the last of the non-avian dinosaurs were wiped out in the fallout from one of the earth's most catastrophic extinction events. They left only bones and traces in the rock behind. Yet there are people who claim that humans actually lived alongside dinosaurs. Young earth creationists have a habit of twisting natural history to fit within the narrow confines of their interpretation of Genesis, and they insist that humans once co-existed with sauropods, tyrannosaurs, ceratopsians and other dinosaurs within the last 6,000 years or so.
To support their fantastical claims, some creationists cite what they believe to be various sculptures, carvings and other artistic representations of dinosaurs made by ancient cultures around the world. Most of these have been discredited as forgeries and misinterpreted objects, but creationists continue to use them as evidence for their peculiar view of earth history. Among the most oft-cited is a petroglyph of what appears to be an Apatosaurus-like sauropod on Kachina Bridge in Utah's Natural Bridges National Monument. According to the fundamentalist-apologist group Answers in Genesis, "The petroglyph of a sauropod dinosaur clearly has important implications—indicating that dinosaurs were indeed known to men after the Flood until they eventually died out and became (apparently) extinct." The assumption is that the petroglyph was intentionally carved by humans to represent a single animal that people had actually seen walking around the landscape in the recent past. A paper just published by paleontologists Phil Senter and Sally Cole demolishes this argument.
Have you ever watched the clouds go by and thought you saw one in the shape of an animal, or seen the "man in the moon"? These are examples of pareidolia—seeing what we believe to be a significant shape or pattern when it isn't really there. This phenomenon also explains the "dinosaur" on Kachina Bridge. Upon close inspection by Senter and Cole, the "sauropod dinosaur" turned out to be made up of distinct carvings and mud stains. It is definitely not a depiction of a single animal, and, viewed in detail, it looks nothing like a dinosaur. The separate carvings and mud stains only look like a dinosaur to those wishing to find one there.
While certainly the most prominent, the supposed sauropod was not the only dinosaur carving creationists thought they saw on the bridge. Three other dinosaur depictions have been said to exist, but Senter and Cole easily debunked these, as well. One of the "dinosaurs" was nothing but a mud stain; a proposed Triceratops was just a composite of petroglyphs that do not represent animals, and what has been described as a carving of Monoclonius was nothing more than an enigmatic squiggle. There are no dinosaur carvings on Kachina Bridge.
The Kachina Bridge petroglyphs were not hoaxes or frauds. They were carved by people who once lived in the region, but there is no indication that any of them represent animals, living or extinct. What creationists thought they saw in the rocks has turned out to be an illusion, but I wonder how many of them will actually admit their mistake?
Senter, P.; Cole, S.J. (2011). "Dinosaur" petroglyphs at Kachina Bridge site, Natural Bridges National Monument, southeastern Utah: not dinosaurs after all Palaeontologia Electronica, 14 (1), 1-5