Ancient crocodiles weighed 1,000 pounds and walked on two legs

Ancient crocodiles weighed 1,000 pounds and walked on two legs. Ancient footprints found in South Korea belong to massive crocodiles that walked on their hind legs, according to a new study published in Scientific Reports.

The tracks were initially thought to have been made by giant pterosaurs, but researchers were shocked to discover the footprints belonged to a crocodile species that walked on two legs like dinosaurs.

“At one site, the footprints were initially thought to be made by a giant bipedal pterosaur walking on the mudflat, we now understand that these were bipedal crocodile prints,” said Dr. Anthony Romilio of the University of Queensland.

“The footprints measure around 24 centimeters, suggesting the track-makers had legs about the same height as human adult legs. These were long animals that we estimate were over three meters in length.

“And while footprints were everywhere on the site, there were no handprints.”

In previous work, a team of paleontologists led by Professor Kyung Soo Kim of Chinju National University found multiple sets of large, well-preserved footprints during excavation at the Sacheon Jahye-ri site in South Korea. 

A recent analysis of the tracks, which date back 110 to 120 million years, revealed that they were made by a new species of crocodylomorph.

“Typical crocodiles walk in a squat stance and create trackways that are wide,” said Professor Kim. “Oddly, our trackways are very narrow looking – more like a crocodile balancing on a tight-rope.”

“When combined with the lack of any tail-drag marks, it became clear that these creatures were moving bipedally.”

“They were moving in the same way as many dinosaurs, but the footprints were not made by dinosaurs.”

Professor Kim explained that dinosaurs and their bird descendants walk on their toes.

“Fossil crocodile tracks are quite rare in Asia, so finding an abundance of nearly one hundred footprints was extraordinary,” said Dr. Romilio.

“As an animal walks, the hind feet have the potential of stepping into the impression made by the hand and ‘over-printing’ it, but we find no evidence of this at these Korean sites.”

“It isn’t due to poor preservation either, because these fossils are spectacular, they even have the fine details of the toe-pads and scales on their soles preserved.”

The newly described crocodile, known as Batrachopus grandis, weighed nearly 1,000 pounds, had razor-sharp teeth and measured approximately 13.1 feet. According to the experts, the massive crocodile likely fed on anything available, including dinosaurs. 

The findings suggest that tracks found at earlier sites, originally believed to have been made by giant pterosaurs, may instead belong to crocodylomorphs. 

The study is published in the journal Scientific Reports.

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By Chrissy Sexton, Earth.com Staff Writer