Velociraptor tracks reveal multipurpose claw

It's one of the most memorable moments from the1993 hit filmJurassic Park: Hot on the trail of a trio of velociraptors, game warden Robert Muldoonfinds his prey in the jungle. But as he levels his shotgun at the escaped dinosaur, Muldoon realizes he's walked into a trap.

"Clever girl," quips Muldoon, as a second raptor emerges from the undergrowth to tear him to shreds with her vicious claws.

Velociraptorskept thelargest of their three forward-pointingtoes raised off the ground as they walked, in order to avoid dulling the blade they used for hunting.But new research,publishedahead ofthe world release ofJurassic World,showsraptorswere also capable of using their hunting clawsfor extra traction.

Tale told by raptor toes

In a new paper published in the journalPaleoWorld,University of Alberta alumnusLidaXing,University of Alberta PhD studentScott Personsand co-authorswrite that not all raptor prints show this telltale sign.

At a paleontology site inChina, Xing, Persons and their team found anumber of tracks withnarrow impressions of the raptors' sharp middletoes.

"Because those footprints are preserved in deep, soft, squishy mud the raptor might have been having a little trouble manoeuvring through that substrate," said Persons.

In order to gain extra traction, hypothesized Persons, the raptors "went ahead and deployed that claw down into the muck. So it was using that claw kind of like a big cleat to help push its way out."

Ancient footprints in China

Their research was based on a series of raptor tracksfoundat a site in China'sSichuanprovince.The tracksdatingto theEarlyCretaceousperiodareat least 100 million years old. The site is "not so terribly different from the badlands of Alberta," said Persons.

Although the conditions weren't right for preserving fossilized dinosaur bones, they were perfect for footprints.

The raptors at the Sichuan site would have been the size of a wolf or coyote. Due to their light bone structure, they might have weighed about 14 or 16 kilograms.

The site includesfootprints from all kinds of dinosaurs, ranging from carnivores to vegetarians with long necks.

Jurassic Park and velociraptors

Jurassic Parkofferedan accurate depiction of raptor footprints, said Persons, even though scientists hadn't yet learned that the dinosaurs kept their middle toes raised.Persons creditsJurassic Parkwith popularizingthe fast-moving dinosauramong children.

"Before that, it was tyrannosaurus rex, triceratops, stegosaurus, brontosaurus," said Persons."Now, velociraptor is probably the second or third best-known dinosaur."

Since the firstJurassic Parkmovie, scientists have confirmed that velociraptors were actually covered in fine feathers, rather than scales. ButJurassic World, which comes out onJune 12, still depicts velociraptors with scales.