Scientists found no frontal footprints, prompting them to start thinking about ancient crocodiles in a completely different context.
Some species of ancient crocodiles likely moved on their hind legs, such as dinosaurs or ostriches, a study based on well-preserved fossil footprints found in South Korea showed.
Nearly 100 traces between 18 and 24 cm long have been preserved in muddy sediment around the lake dating back to the early Cretaceous, the last part of the Mesozoic, or from 110 to 120 million years before the new era.
The international team behind the discovery says this is likely to undermine our perception of crocodiles.
People tend to think of crocodiles as animals that are quite lazy and lie on the banks of the Nile or rivers in Costarica. It doesn’t occur to anyone to wonder what would happen if such an animal was moving on its hind legs, such as an ostrich or a T. rex, Martin Lockley, a professor emeritus at the American University of Colorado, told BBC News.
The study will certainly spark a lively debate because not all researchers will necessarily accept the interpretation of American scientists.
The results of the study were published Thursday night in the journal Scientific Reports, alongside Us-American and South Korean scientists.
At first, they thought that fossilized footprints discovered in the area of present-day South Korea belonged to an ancient flying reptile, a pterosaur, an ancestor of modern birds, but after research scientists believe they belong to crocodiles that moved on two hind legs.
At one site we found prints that we believed belonged to giant pterosaurs, but now we assume they are crocodile tracks, said one of the study’s authors, Anthony Romilio, a paleontologist at the University of Queensland.
The footprints are about 24 centimetres long, suggesting that the height of the creatures’ legs left them was about the same as the height of an adult man’s legs, he explained.
And while footprints were found all over the site, the front-foot marks and hands were not found, Romilio said.
The head of the research, Kyung Soo Kim of the National South Korean University in Chinju, said the footprint trajectory was “very narrow” and that “it looks like the trajectory left behind by a crocodile balancing on a thin rope,” and it is known that crocodiles leave behind a wide motion curve.
When we added to these findings the fact that there were left marks of tail pulling, it became clearer to us that these creatures were moving on two hind legs, he said.
In addition, footprints do not resemble those left behind by dinosaurs moving on their toes. Crocodiles move a full foot, leaving clear traces of heel, like humans, Kim explained.