Researchers find evidence that tyrannosaurs hunted in packs

[jimmy olsen]

 

http://www.theguardian.com/science/2014/jul/23/tyrannosaurs-hunted-packs-tracks-canada

Researchers find first sign that tyrannosaurs hunted in packs

Discovery of three sets of dinosaur trackways in Canada reveals that predators were running together
   
    Ian Sample, science editor
    The Guardian, Wednesday 23 July 2014 19.36 BST

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 north-east British Columbia - in the west of Canada - 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.

• This article was amended on 24 July 2014. The original incorrectly suggested the tracks were found in the north-east of Canada. They were actually found in north-east British Columbia, which is in the west of Canada. This has been corrected.   

[Razgovory]

Packs of what?

[viper37]

http://www.theguardian.com/science/2014/jul/23/tyrannosaurs-hunted-packs-tracks-canada

Researchers find first sign that tyrannosaurs hunted in packs

Discovery of three sets of dinosaur trackways in Canada reveals that predators were running together
   
    Ian Sample, science editor
    The Guardian, Wednesday 23 July 2014 19.36 BST

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 north-east British Columbia - in the west of Canada - 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.

• This article was amended on 24 July 2014. The original incorrectly suggested the tracks were found in the north-east of Canada. They were actually found in north-east British Columbia, which is in the west of Canada. This has been corrected.   

I hope Spielberg is reading this for his next Jurassic Park... 

[Valmy]

He better properly name it 'Cretaceous Park' this time 

[Malthus]

I always thought they only hunted in pairs, like Mormons.

[Siege]

How.do.they.know the tracks were left the same day, the same hour?
There could be a million years between each set of tracks.

[Tonitrus]

How.do.they.know the tracks were left the same day, the same hour?
There could be a million years between each set of tracks.

They couldn't be that far apart if Jesus was able to ride them.

[CountDeMoney]

Packs of what?

Gum. Collect all their trading cards.

[Habbaku]

Packs of what?

Gum. Collect all their trading cards.

[Agelastus]

How.do.they.know the tracks were left the same day, the same hour?
There could be a million years between each set of tracks.

Siege, do you know how the tracks were preserved?

[I'll admit I'm making an assumption about the method here, but there seems to be a big clue in the story.]

[alfred russel]

Siege, do you know how the tracks were preserved?

I'm going to go WAY out on a limb here and guess he does not.

[viper37]

He better properly name it 'Cretaceous Park' this time 

don't interfere with the marketing department

[Eddie Teach]

I'm more interested in Precambrian Park.

[The Brain]

I had a Cambrian explosion this morning.

[Malthus]

I'm more interested in Precambrian Park.

I can picture the plot now: "oh no, we are being chased by ... a sponge-like thing!" 

http://universe-review.ca/R10-19-animals.htm