ad ponds oases."
The 2.4-inch-wide tail-drag marks which are up to 24 feet long are a special discovery because there are fewer than a dozen dinosaur tail-drag sites worldwide, Seiler says. Four tail drags were within the 10 plots he surveyed, and there are others nearby.
"Dinosaurs usually weren't walking around with their tails dragging," he says.
Potholes or Prints from Four Kinds of Dinosaurs?
Chan first visited the site of the dinosaur tracks in 2005 with a BLM ranger who was puzzled by them. Chan initially called them potholes, which are erosion features common in desert sandstone, "but I knew that wasn't the whole story because of the high concentration and because they weren't anywhere else nearby but along that one surface."
Seiler first saw the site in 2006. "At first glance, they look like weathering pits a field of odd potholes," he says. "But within about five minutes of wandering around, I realized these were dinosaur footprints."
One anonymous reviewer of the Palaios study still believes the holes are erosion features. The study argues the impressions are from dinosaurs because:
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- They are the correct size for tracks made by big animals, and are limited to a single rock bed.
- Four different kinds of footprint shapes are seen repeatedly in 14 percent of the impressions, and they include obvious claw, toe and heel marks. The other impressions "are clearly similar."
- One-third of the prints are surrounded by small ridges or mounds. Such features would be expected when animals stepped in wet sand.
- The tracks "are rarely flat and are typically oriented at an angle into the sediment and indicate a clear direction of travel" to the west-southwest. Seiler says the direction the dinosaurs walked "either was dictated by the large dunes that bounded this wet area, or it could be communal behavior, like walking together as a pack."
. New dinosaur species found in Montana2
. Emory paleontologist reports discovery of carnivorous dinosaur tracks in Australia3
. Dinosaur from Sahara ate like a mesozoic cow4
. Massive dinosaur discovered in Antarctica sheds light on life, distribution of sauropodomorphs5
. Unusual fish-eating dinosaur had crocodile-like skull6
. Seismic images show dinosaur-killing meteor made bigger splash7
. New dinosaur from Mexico offers insights into ancient life on West America8
. Quantum weirdness, parallel worlds, dinosaur poop, and the ultimate fate of the universe...9
. Grand Canyon may be as old as dinosaurs, says new study10
. Medical College researchers find dinosaur clues in fat11
. Genetic sequencing of protein from T. rex bone confirms dinosaurs link to birds