April 9, 2013
River-Bottom Claw Marks Provide Evidence Of Dinosaurs’ Swimming Prowess
redOrbit Staff & Wire Reports - Your Universe Online
Researchers have found new evidence that dinosaurs were excellent swimmers, according to a study published in Monday´s edition of Chinese Science Bulletin, an academic journal co-sponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China.In fact, an international team of experts, which included University of Alberta graduate student Scott Persons, located what is being called “strongest evidence ever found that dinosaurs could paddle long distances."
They examined a series of unusual claw marks that were left on the bottom of a Chinese river that is known to have been commonly used by traveling dinosaurs. In addition to easily identified footprints of several Cretaceous era animals, including giant long-neck dinosaurs, Persons and his colleagues discovered claw marks that they claim clearly indicates a coordinated left-right, left-right progression.
“What we have are scratches left by the tips of a two-legged dinosaur's feet,” Persons said in a statement. “The dinosaur's claw marks show it was swimming along in this river and just its tippy toes were touching bottom.”
The claw marks covered a distance of 15 meters (nearly 50 feet), which the authors cite as evidence that dinosaurs had the ability to swim using coordinated leg movements. These particular tracks were made by a carnivorous theropod dinosaur which is believed to have stood an estimated one meter at the hip.
Based on fossilized rippling and the evidence of mud cracks, the researchers report that the river — which is located in what is now the Szechuan Province — went through both wet and dry cycles more than 100 million years ago. Persons describes the river bed as a “dinosaur super-highway,” adding that it has provided he and his colleagues with several other full dinosaur footprints, including those of other theropods and gigantic four-legged sauropods.
Unfortunately, since the researchers only have the river-bottom claw marks to work with, Persons said that they are unable to identify exactly which dinosaur was responsible for paddling across the body of water. However, he believes it could have been either an early tyrannosaur or a Sinocalliopteryx — two species of predators which were known to have lived in that area of the Asian country.