Social Dinosaurs

Damnit, I knew these guys ahd to have more complicated behavior than they showed when I was a kid...

Scientists have discovered the remains of seven carnivorous dinosaurs that traveled in packs throughout an area of southern Argentina nicknamed Jurassic Park, one of the paleontologists told AFP.

"This is a new type of carnivorous dinosaur, known as the Mapusaurus, that lived some 90 million years ago. Seven examples of different ages were found buried, which could suggest that they lived in packs," Argentine paleontologist Rodolfo Coria, who made the discovery along with Canadian Philip Currie, told AFP.

Coria said that, up to now, no one knew of any "carnivorous animals of this size" -- weighing six tonnes and standing 12 to 13 meters, or 39 to 43 feet, tall -- that had a herd instinct.

He said it was only case of its kind in the entire world.

Scientists had previously believed that the animals traveled solo, but the find in southwestern Argentina's Neuquen province for the first time revealed a sociable side to the creatures, which are believed to have hunted together.

From here.

The newly revealed species is one of the biggest carnivores ever to have walked the Earth, dinosaur experts say.

At least seven of the animals were uncovered together in a mass fossil graveyard in western Patagonia, a region famous for giant-dinosaur remains.

Living some 100 million years ago, the largest specimen was more than 40 feet (12.5 meters) long.

Researchers say the new species, named Mapusaurus roseae, is possibly even larger than its close relative Giganotosaurus, which in 1995 took T. rex's crown as the world's biggest known carnivorous dinosaur.

The find is also one of the first to suggest giant meat-eating dinosaurs lived in groups.

[...]

The skeletons showed no signs of disease, Coria says, so the animals were apparently victims of some sudden catastrophic event.

"The burial is formed 100 percent by Mapusaurus bones," he added. "The chances they had been deposited randomly are extremely low."

Coria and Currie say the different sizes of the animals point to the creatures living as a group.

"Most are medium-sized animals, with a very few young and a very few old," Coria said. "It's a normal composition for [a pack] animal population."

The find hints that two-legged, or theropod, dinosaurs such as T. rex might not have been solitary predators as previously thought, but may have hunted in groups.

From NatGeo.

It also suggests the Jurassic was a different ecosystem than you might have expected.