University of Queensland researchers studied thousands of small dinosaur tracks in central-western Queensland where 95-million-year-old prints are preserved in thin beds of sandstone deposited in a shallow river when the area was part of a vast, forested floodplain.
"Many of the tracks are nothing more than elongated grooves, and probably formed when the claws of swimming dinosaurs scratched the river bottom," Queensland doctoral candidate Anthony Romilio said.
"Some of the more unusual tracks include 'tippy-toe' traces -- this is where fully buoyed dinosaurs made deep, near vertical scratch marks with their toes as they propelled themselves through the water.
"It's difficult to see how tracks such as these could have been made by running or walking animals," he said in a university release Wednesday.
The swimming dinosaur tracks at Lark Quarry Conservation Park belonged to small, two-legged herbivorous dinosaurs known as ornithopods, he said.
However, Romilio said, the study may contradict the long-held belief the huge numbers of tracks are the result of a dinosaur "stampede."
"Taken together, these findings strongly suggest Lark Quarry does not represent a 'dinosaur stampede.'"
"A better analogy for the site is probably a river crossing," he said.