The collective noun is a terror of tyrannosaurs: a pack of the prehistoric predators, moving and hunting in numbers, for prey that faced the fight of its life.
That tyrannosaurs might have hunted in groups has long been debated by dinosaur experts, but with so little to go on, the prospect has remained firmly in the realm of speculation.
But researchers in Canada now claim to have the strongest evidence yet that the ancient beasts did move around in packs.
At a remote site in the country’s northeast, they uncovered the first known tyrannosaur trackways, apparently left by three animals going the same way at the same time.
Unlike single footprints which have been found before, tyrannosaur trackways are made up of multiple steps, revealing the length of stride and other features of the animal’s movement. What surprised the Canadian researchers was the discovery of multiple tracks running next to each other – with each beast evidently keeping a respectable distance from its neighbour.
Richard McCrea at the Peace Region Palaeontology Research Centre in British Columbia was tipped off about one trackway in October 2011 when a hunting guide working in the area emailed him some pictures. The guide had found one footprint that was already exposed and later uncovered a second heading in the same direction. McCrea made immediate plans to investigate before the winter blanketed the site with snow.
He arrived later the same month and found a third footprint that belonged to the same trackway under volcanic ash. But the real discovery came a year later, when the team returned and uncovered two more sets of tyrannosaur tracks running in the same south-easterly direction.
“We hit the jackpot,” said McCrea. “A single footprint is interesting, but a trackway gives you way more. This is about the strongest evidence you can get that these were gregarious animals. The only stronger evidence I can think of is going back in a time machine to watch them.”
The footprints were so well-preserved that even the contours of the animals’ skin were visible. “You start wondering what it would have been like to have been there when the tracks were made. The word is terror. I wouldn’t want to meet them in a dark alley at night,” McCrea said.
From the size of the footprints, the researchers put the beasts in their late 20s or early 30s – a venerable age for tyrannosaurs. The depth of the prints and other measurements suggest the tracks were left at the same time. They date back to nearly 70m years ago.
Close inspection of the trackways found that the tyrannosaur that left the first set of prints had a missing claw from its left foot, perhaps a battle injury. Details of the study are published in the journal Plos One.
During the expedition, McCrea’s team unearthed more prehistoric footprints from other animals, notably hadrosaurs, or duck-billed dinosaurs. Crucially, these were heading in all sorts of directions, evidence, says McCrea, that the tyrannosaurs chose to move as a pack, and were not simply forced into a group by the terrain.
“When you find three trackways together, going in same direction, it’s not necessarily good evidence for gregarious behaviour. They could be walking along a shore. But if all the other animals are moving in different directions, it means there is no geographical constraint, and it strengthens the case,” said McCrea.
Document reveals how the White House cheered up Trump after his meltdown at #MAGA rally in Dallas
Last week, President Donald Trump sought to shore up political support in Texas by holding a campaign rally in Dallas.
During the rally, Trump told the crowd how he hated it when his children told him what they learned in school.
The president also suffered a meltdown and offered the crowd his impersonations.
Fox Nation host Tomi Lahren on Wednesday revealed a note she'd received from the White House reading, "Tomi, thank you for everything. Best wishes."
‘Hard to overstate’ how badly Taylor’s testimony damaged Trump: Ex-federal prosecutor
On Wednesday, former federal prosecutor Renato Mariotti wrote for Politico Magazine that the testimony of Ukraine envoy William Taylor was devastating for President Donald Trump — and that if he keeps trying to deny wrongdoing, it will only get worse and maybe even force Senate Republicans' hand against him.
"It’s hard to overstate how much damage the testimony of Ukraine envoy William Taylor inflicted on President Donald Trump’s defense in the ongoing impeachment inquiry," wrote Mariotti. "On its face, Taylor’s testimony Tuesday established the quid pro quo that Trump has denied for weeks. But more importantly, Taylor’s detailed notes of the 'highly irregular' policy-making that he witnessed over the summer provide a roadmap to future testimony that could be even more harmful. Republicans have already begun to retreat from their 'no quid pro quo' line, but they will have to keep retreating because Taylor has almost single-handedly decimated the few witnesses who have provided some testimony that is favorable to Trump."
‘How much did you get for your soul?’ Internet dogpiles Lindsey Graham after he walks back criticism of SCIF raid
On Wednesday, Sen. Lindsey Graham (R-SC) appeared to have reached the limit of his capacity to defend his own party when a gang of House Republicans raided a sensitive, compartmented information facility where an impeachment hearing was taking place and illegally bringing in recording equipment. Initially Graham criticized the Republicans behind the stunt, calling it "nuts."
Later, however, he changed his mind and decided the demonstration was fine with him, offering this explanation:
I was initially told House GOP took the SCIF by force – basically like a GOP version of Occupy Wall Street.