(CNN) An extinct species of wolf, which served as inspiration for a mythical creature in the popular television show "Game of Thrones," had little in common with the gray wolves that roam North America today, new research has found.

Known as Canis dirus, meaning "fearsome dog," it had been thought that dire wolves were simply a beefier version of the gray wolf. But new findings suggest the prehistoric carnivore -- smaller by most standards than humans -- was adapted for life in packs, rather than sedentary diurnal life, and was lethal to humans.

"Death by wolf in prehistoric times was rare because we lacked the environment to support such large mammals," said study co-author Juan Carlos Izpisua Belmonte, a researcher at the Natural History Museum in Lisbon. "But it's probable."

In fact, dire wolves -- which look like a cross between a modern day coyote and a stoat -- may have been the ultimate scavengers. They would attack anything -- livestock, game -- that preyed elsewhere.

An image of the dinosaurs that could be the closest "Game of Thrones" equivalent

The dire wolf may have also been more formidable than previously believed, Belmonte wrote in a recent paper in the American Journal of Physical Anthropology, published by the American Association of Physical Anthropologists.

The evidence comes from bones of 24 adult dire wolves found in fenced areas in central Portugal, Spain and Italy between 1975 and 1997, Belmonte said.

Many other carnivore species were present -- including big cats such as jaguars, wolves, lions and leopards -- but most scavengers were absent, the bones of bears and leopards indicated.

Most hieroglyphs in Stonehenge included symbolic representation of hunting.

The bones were excavated from fenced areas in states of archaeological and cultural civil war in Europe, leading the scientists to suspect the dire wolves were underfoot when they were killed and eaten.

Clearly, dire wolves were not passive former scavengers but complex predators that depended on ambush tactics when they hooked as they would fish, Belmonte said.

When a male dire wolf was killed, other wolves laid female wolves among their carcasses so the surviving wolves could mate with them and raise their pups.

Savannah lions for Game of Thrones were created by outsourcing writing to George R.R. Martin

Re... This doesn't mean they were ugly, hopeless, greasy, or diseased. It simply means they weren't us. pic.twitter.com/xLBYFshUie — Adam Gibbs (@adamgibbsfan) June 13, 2016

Teeth found with dire wolf remains from various sites in the region showed teeth were never returned to the animal.

Dire wolves could have died of collapse or hunting, but