Raptor dinosaurs much bigger than previously thought

Scientists have found tracks in the Fujian province of southern China that change the perception of the human-sized raptor dinosaurs portrayed in Jurassic Park as far bigger.

The raptor dinosaurs would have roamed the northern hemisphere 95 million years ago.

There were a range of sizes in the species with the latest fossilised footprint revealing some were as long as five metres with legs as tall as 1.8 metres.

"These guys were very slender, if you had an ostrich on hormones or if you think of an emu with its neck sticking up that would be about the length of these guys' legs," University of Queensland researcher Dr Anthony Romilio told AAP.

"If it was a six-foot-tall person that would be the same size as its hip or a very large horse is a good comparison."

This type of raptor dinosaur, a species called Troodontids in the Velociraptor family with similarities to birds, would have existed during the late Cretaceous period - 30 million years before dinosaurs became extinct.

Some tracks show raptors had footprints just 10 centimetres long and could have fit in the palm of your hand while this latest discovery shows some were substantially larger.

"It would be something that is very intimidating if you came across it," Dr Romilio said.

The creatures would not have stood up to a bulky carnivorous dinosaur but may have chosen to be nocturnal and attacked smaller species, he added.

"This style of dinosaur had greater hearing potential and that would be more of an advantage in the dark," he said.

"Who knows if it was preying on other dinosaurs while they were napping or other mammal species."

The two-toed tracks were discovered in 2020 alongside a plethora of other footprints by members of the public who notified the China University of Geosciences.

The discovery is exciting for scientists as it supports recent bone evidence found in the United States that shows dinosaurs were becoming bigger when living closer to the Arctic circle.

"They were in an environment where other meat-eating dinosaurs weren't there at all so it seems these slender raptor dinosaurs found themselves in a place where they could really thrive and get bigger and larger," Dr Romilio said.

The species may have adapted to extended darkness in winter and prolonged summers.

Researchers will now investigate whether these dinosaurs diversified south in this area of China.

The research paper is published in iScience - Cell Press.

Australian Associated Press