Trackways , or collections of two or more consecutive tracks, are rich sources of information for paleontologists. For example, most of the trackways discovered so far don't include the snakelike impressions that would come from a dragging tail. This means the dinosaurs making the tracks walked with their tails held up off the ground.
The lack of drag marks also means dinosaurs held their bodies up over their legs, like horses , rather with their legs splayed out like alligators. Researchers can also calculate the speed the dinosaur moved by comparing the length of the tracks to the distance between them. In general, if the length of the stride is more than four times the length of the foot itself, the dinosaur was running, not walking. Researchers have also used computer models to analyze tracks and estimate the height of the dinosaur's hip [source: Henderson ].
But there's more to be learned from trackways than how a single dinosaur species walked or ran. A collection of tracks can reveal information about social behavior. This isn't necessarily true of a trackway full of lots of overlapping tracks, such as the Davenport Ranch tracksite in what is now Texas. This area contains the prints of 23 different sauropods -- four-legged, herbivorous dinosaurs [source: American Museum of Natural History ]. While some researchers believe smaller dinosaurs followed along in larger dinosaurs' tracks, it's hard to tell exactly how much time passed between the formation of each set of prints.
However, collections of parallel tracks moving in the same direction, such as the ones shown above, suggest that some dinosaurs may have traveled in groups. A single set of tracks that covers lots of area without much overlap suggests that the dinosaur may have systematically looked for food. There's one important piece of information that often can't come from trackways -- what kind of dinosaur the tracks belonged to.
Very big dinosaurs had lots of muscle and padding on their feet, so their preserved footprints don't look much like the bones scientists have for identification. And since bones fossilize best when buried quickly -- and prints fossilize best when buried gradually -- it's rare for researchers to find preserved tracks next to the skeleton of the dinosaur that made them. Sign up for our Newsletter! More than one consecutive step by the same animal is known as a trackway.
Geological Survey via Flickr CC0 1. A dinosaur could leave innumerable footprints, but only one skeleton. However, for tracks to form and preserve, conditions must be just right. The consistency of the ground influences the shape, size and depth of the track and any associated underprints.
For a perfect print, the ground can't be too hard or too soft. If the ground is too hard, the resulting print would be very shallow, show very limited detail or not form at all. If the ground is too soft, the track could collapse in on itself. If these prints survive, they would look distorted. For example, digit marks could turn into slits instead of distinct fingers or toes. Once prints form, they could easily degrade and be filled or washed away.
The Red Gulch dinosaur tracksite in Wyoming, USA, features numerous fossil footprints formed when the area was the coast of a prehistoric sea. The soft ground of ancient shorelines or mudflats are common locations to find fossilised dinosaur tracks. Unlike bones, which needed to be covered quickly once a dinosaur died to preserve as much of the animal as possible, tracks first needed to be baked hard by the Sun.
This would have taken anywhere from days to months depending on the conditions. In some places, fossilised tracks make it look as though dinosaurs would have been walking up impossibly steep inclines, such as the near vertical Cal Orcko tracksite in Bolivia. But this is where the geology of the ground has changed dramatically over millions of years. The dinosaurs would have been walking over much flatter ground - the Cal Orcko site was a riverbed around million years ago.
The dinosaur tracks at the Cal Orcko site in Bolivia are found on an almost vertical cliff face. Around million years ago, this was a riverbed. Eight dinosaur species have been identified on this site.
Dinosaur tracks are a type of trace fossil. These are evidence of an animal's activity when it was alive, but are not part of the animal itself.
Scientists that study this type of fossil are known as ichnologists. It is almost impossible to tell exactly which species of dinosaur made a track - for example, many theropods have similar-looking three-toed feet. Additionally, bones and tracks don't line up exactly - the bones lack the soft tissue that was part of the foot or hand that made the print.
Bones found close to a tracksite are unlikely to belong to the dinosaur that made the tracks, as they would have fossilised under different conditions. Termination trackways, where a dinosaur fossil is associated with its final steps, are exceptionally rare. The hammer is to show scale.
Image courtesy of Patrick Getty. Not all kinds of rock can contain dinosaur footprints and other trace or impression fossils. Clearly, the initial material in which tracks are made has to be soft enough to receive an impression, yet firm enough to hold the shape. Dinosaurs emerged about million years ago and roamed the Earth for over million years.
About 65 million years ago, they vanished from the fossil record. Scientists have come up with many theories as to why the dinosaurs became extinct. A widely accepted theory, based on very strong evidence, suggests that it was due to the impact of an asteroid. Dinosaurs belong to a group of reptiles known as archosaurs.
Modern day archosaurs include crocodiles and birds. An archosaur is defined by an extra hole in the skull, located in front of the eye. Dinosaurs are further defined by a hole in the middle of the pelvis. No other animal on Earth has ever exhibited this feature. The hole in the pelvis allowed dinosaurs to walk with their legs directly beneath them, as opposed to the sprawling stance of other reptiles.
Dinosaur footprint trace fossils have been discovered on all continents except Antarctica. They have been found in layers of sedimentary rock ranging in age from million years ago to 65 million years ago. Paleontologists have learned much about dinosaurs from their footprints, mainly by comparing them with living animals.
Mammals are the best modern organisms for comparison because they walk erectly, like the dinosaurs. For example, elephant tracks and Apatosaurus dinosaur tracks are very similar.
What is a Fossil? How Fossils Form. Fossils From Living Things. Fossil Footprints. Skip to main content. K-5 GeoSource. PDF version Teaching and Learning Focus In the last investigation, students learned about body fossils, fossils that are the actual organism or some part of it or the imprint of the organism or some part of it.
Materials Needed Per group: Plaster of Paris plastic measuring spoons stirring sticks water milk carton with the top portion cut off two measuring cups non-stick cooking spray brown paint paint brush plastic dinosaur models safety impact goggles for each student blunt knives to split Plaster of Paris Images to be viewed by the class: Images of Footprints Images of Trace Fossils For the instructor: flip chart or whiteboard markers Safety Use disposable craft sticks for mixing the Plaster of Paris.
Setting the Scene Many of your students will not think of ancient tracks, trails, burrows, feeding marks, and resting marks preserved in rock as fossils. Image of a Footprints Word Document 2. What may have made the imprints in the sand or mud? What can you tell about the size of whatever made the imprints?
What does the pattern of the imprints tell you about the behavior of whatever may have made them? Presenting the Investigation Question After the scene is set, introduce your students to the investigation question: How does a footprint become a fossil? Have your students brainstorm ideas about how this investigation question could be investigated. How would you design an experiment that could be used to test the investigation question?
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