New discovery shows tyrannosaurs were born 'ready to hunt'

The fossilised jaw and claw bones, the researchers said today, represented two species from the group called tyrannosaurs, the leading predators in Asia and North America during the Cretaceous Period toward the end of the dinosaur age.

New discovery shows tyrannosaurs were born 'ready to hunt'

Scientists for the first time have found embryonic remains from a group of ferocious meat-eating dinosaurs showing these record-size babies looked a lot like adults and were “born ready” to hunt.

The fossilised jaw and claw bones, the researchers said today, represented two species from the group called tyrannosaurs, the leading predators in Asia and North America during the Cretaceous Period toward the end of the dinosaur age.

The bones indicated that these were bigger than any other known dinosaur babies – one metre long, or the size of a medium dog – and hatched from what must have been enormous eggs.

They may exceed the 43cm length of the largest dinosaur eggs ever known.

The roughly 77 million-year-old jawbone, about 3cm in length, was unearthed in Montana and may belong to a species called Daspletosaurus.

The roughly 72 million-year-old wedge-shaped claw came from Canada’s Alberta province and may belong to a species called Albertosaurus.

Both are slightly smaller cousins of Tyrannosaurus rex. The largest-known tyrannosaurs topped 12 metres long and eight tonnes in weight.

The jaw possesses distinctive tyrannosaur traits, including a deep groove inside and a prominent chin.

University of Edinburgh paleontologist Greg Funston said the scientists were amazed at how similar the embryonic bones were to older juvenile and adult tyrannosaurs.

The jaws boasted functional teeth, added the lead author of the research published in the Canadian Journal of Earth Sciences.

“So although we can’t get a complete picture, what we can see looks very similar to the adults,” Dr Funston said.

It appears that tyrannosaurs were “born ready to hunt, already possessing some of the key adaptations that gave tyrannosaurs their powerful bites.

“So it’s likely they were capable of hunting fairly quickly after birth, but we need more fossils to tell exactly how fast that was.”

Originally published at Rte