Social T. rex? New research shows that carnivores are hunted in packs

Researchers have discovered a stack of dinosaurs at the Grand Staircase-Escalante National Monument – a family of the giant Tyrannosaurus rex – which leads to the conclusion that they all died in the same flood event at the same time and walked together in a ‘deceptive’ way. social unity.

The Rainbows & Unicorns Quarry on the southern Utah site is groundbreaking because the mainstream story surrounding these dinosaurs that roamed the earth 76.4 million years ago is that they were solitary prey animals that had the refinement to launch a coordinated attack. to feed to deliver their next meal.

“It takes a lot of brain power,” according to Alan Titus, paleontologist for the Paria River District, the Bureau of Land Management.

Titus said the finding is “somewhat controversial” because the 2014 finding illustrates that the giant dinosaurs traveled together and probably joined in murder – such as the pride of lions or wolf packs today. Paleontological researchers mostly did not dismiss the idea that giant carnivorous dinosaurs were capable of such social action.

In this find, scientists excavated a family of four, possibly five individuals of the T. rex, including a young juvenile about 4 years old and a fully developed adult in his mid-20s.

The site has been repurposed using a variety of scientific techniques revealing that it is the first tyrannosaur mass massacre in the southern United States. Using a series of tests and analyzes on the remains of the original site, researchers found that the dinosaurs perished in a single flood event, were buried in fine mud, dug up and buried in a sandbank.

“And there it is, a very sad day in southern Utah 76 million years ago,” Titus said.

Alan Titus, Land Management Bureau

The findings were published by the publication in the open-access scientific journal PeerJ Monday. They were produced by a team of researchers from the BLM, Denver Museum of Nature and Science, the University of Arkansas, Colby College of Maine and James Cook University in Australia.

The specimens excavated from the unique site for fossil bones exceeded the expectations raised even by its high nickname.

Titus said the name was derived from the teasing of former colleagues who find him over his eternal excitement over any new find.

“I’m always about rainbows and unicorns,” he said, but emphasized that he had told his colleagues that it was a rainbow and unicorn find.

Researchers remain enthusiastic that the quarry will reveal additional answers the more they dig into it.

“The new site in Utah contributes to the growing body of evidence showing that tyrannosaurs are complex, large predators capable of having social behaviors common to many of their living relatives, the birds,” said Joe Sertich, project curator of dinosaurs at the Denver Museum of Nature and Science. “This discovery should be the turning point for reconsidering how these top carnivores behaved and hunted in the Northern Hemisphere during the Cretaceous.”

Titus explained that large predators usually do not cooperate in the search for food – they do compete against each other.

But as in the case of lions and wolves, which have complex and sophisticated social roles, Titus said a modern-day second cousin of the dinosaur – the Harris falcon – is the only known bird of prey that cooperatively hunts and participates in the common rearing of their little ones. .

Alan Titus, Land Management Bureau

“Localities (such as Rainbows and Unicorns Quarry) that provide insights into the possible behavior of extinct animals are particularly rare and difficult to interpret,” said world-renowned tyrannosaur expert Philip Currie. ‘Traditional excavation techniques, supplemented by the analysis of rare earth elements, stable isotopes and charcoal concentrations, convincingly show a synchronous death event at the Rainbows site of four or five tyrannosaurids. Undoubtedly, this group died together, which contributes to an increasing amount of evidence that tyrannosaurids were able to work together as fusing packs. ‘

The idea that tyrannosaurs were social with complex hunting strategies was formulated more than 20 years ago by Currie.

Alan Titus, Land Management Bureau