You know what they say about dinosaurs with big feet? They left big holes.
Some of the largest footprints known to science were made 70 million to 90 million years ago, when a type of dinosaur believed to be a titanosaur galumphed across the muck in central Asia. A few of these mud tracks filled with sand and silt, which hardened like plaster. Long after the titanosaur died off, the casts in the sand remained. We know about these big feet because a Mongolian paleontologist discovered a few of them in the Gobi Desert in August.
And what a titanic foot the dinosaur must have had. One of the most detailed tracks was a convex mound 42 inches in length, with impressions of the animal’s massive nails. By U.S. shoe standards, it would stretch its sneakers to a size 104. (The world’s largest human feet max out at about 15 inches , about a size 23 or 25.) The print was also much wider than any human foot, at 30 inches across.
“The footprint is one of the biggest known footprints in the world,” said Shinobu Ishigaki, a researcher at the Okayama University of Science in Japan and a member of the joint Mongolian-Japanese expedition to the Gobi, in an email to The Washington Post. The researchers announced their discovery of the footprint, roughly the size of a popular IKEA kitchen table, on Friday in Japan.
In Morocco and France, paleontologists have also found footprints more than a yard long. “However the Mongolian one is very well preserved,” Ishigaki said, “with three clear claw marks.” The size of the dinosaur cannot be determined easily from the footprints, but Ishigaki and his colleagues estimate it was two dozen to three dozen yards long.
Paleontologists have been hunting for dino prints in Mongolia since 1957, when a researcher stumbled upon dozens of tracks in the cold, dry desert. As Ishigaki and his colleagues reported in the journal Geological Quarterly in 2009, the Gobi is something of a fossilized footprint mother lode: Between 1995 and 2008, the scientists found more than 20,000 preserved tracks belonging to a variety of dinosaur species.