Free Dinosaurs Without Bones by Anthony J. Martin Page A

might have been stalking the sauropod but did not jump onto it there. Instead, the tracks just weren’t preserved after the point where they disappear. So we don’t really know whether the theropod was going after this sauropod or not. (By the way, if you want to see this trackway, don’t go to Texas, unless you like looking at rectangular holes in riverbeds there. In 1940, Bird and many laborers extracted the trackway and took it to New York City, where it is now displayed in the American Museum of Natural History.)
    Within a mile of this trackway, though, are elongated dinosaur tracks that may reflect evidence of stalking behavior, connecting to speculations mentioned previously that some theropods went fishing. Glen Kuban, a paleontologist who has studied and mapped the Paluxy River dinosaur tracks for more than twenty years, wondered whether a few of the theropod tracks there were a direct result of their stalking fish in shallow water, like modern grizzly bears seeking salmon. His reasoning was based on how a few trackways show where their makers went from normal digit impressions to those including metatarsal prints. This meant the dinosaurs were sinking more deeply into the mud, causing their footprints to become elongated.
    Wait, metatarsal impressions? Where have we heard about those before? That’s right, these are associated with trace fossils where theropods voluntarily squatted. So these elongated tracks could have been made either through the dinosaurs walking from spots with firm mud to spots with squishier mud (involuntary), or they could have occurred from these dinosaurs lowering their bodies while walking (voluntary). When fishing without a pole or net, the best way to catch fish is to get your tools closer to the water surface, and for a theropod that would have meant lowering its arms and mouth. Although this is a difficult hypothesis to test further, it is nice to have a more dashing alternative to one that simply states, “They waded into squishy mud and kept going.”
    Have paleontologists ever discovered theropod tracks connected to a kill site? Not yet, but some Late Jurassic theropod tracks andother circumstantial evidence of feeding are associated directly with sauropod bones. I was lucky enough to see these trace fossils during the summer of 2005 while passing through Thermopolis, Wyoming. My wife Ruth and I had stopped to see the Wyoming Dinosaur Center there, but also took a guided tour of a nearby dinosaur dig site. The site not only had an impressive array of sauropod bones exposed but also included (more significant) dinosaur tracks.
    There, clustered around the skeleton of a juvenile Camarasaurus , were three-toed tracks. Researchers who worked on this site had also found sauropod tracks, showing they also lived in the area, but found ominous toothmarks on the bones along with shed teeth of juvenile and adult Allosaurus . The tracks were also about the right size and shape for this formidable predatory dinosaur. Additional trace fossils in the sauropod skeleton included large rounded stones. These were interpreted as gastroliths originally within the body cavity of the sauropod, exposed by the theropods as they chowed down on the Camarasaurus . As a result, the researchers concluded that this was a feeding ground, perhaps after a kill or—perhaps less exciting to most people—following some other cause of death for the sauropods, which brought in allosaurs to scavenge. More compelling, it conjures a scene of an adult Allosaurus and its offspring dining together on the remains of a young and then-recently departed sauropod.
    Other Cool Stuff You Probably Didn’t Know about Dinosaur Tracks
    Because there are so many dinosaur tracks recorded in Late Triassic through Late Cretaceous rocks worldwide, the chances are good that a few unusual or otherwise stimulating insights might be conveyed by some of them. Sure enough, some dinosaur tracks tell amazing stories. The following is a short