Amarok isn't just a popular open source media player, it is a figure in Inuit mythology with a lot of ties to the field of cryptozoology.  Amarok was a giant wolf who would "hunt down and devour anyone foolish enough to hunt alone at night."  Amarok does not travel in a pack (thank goodness for small favors) but is a lone wolf.

A lot of people like to look for real world sources of legend, and in this case the source is often said to be the giant wolves of yore.  The dire wolf, for example, was indigenous to North and South America from between 1.8 million years ago to 10,000 years ago, only dying out at the end of the Pleistocene.  

The precursors to the Inuit people would have traveled across the Bering land bridge alongside dire wolves, so to speak.  The dire wolf would have been a familiar figure, and more's the pity, because it was a tenacious predator, about five feet long, weighing almost 200 pounds.

Another candidate is the hyaenodon, which is an extinct relative of the modern hyaena.  Hyaenodons were members of the "large and furry" cohort of animals which flourished during the Miocene.  They were large, in keeping with their prey (woolly mammoths and woolly rhinoceros) and competition (dire wolves and Aphycyonidae).  

Although hyaenodons came in all shapes and sizes, Hyaenodon gigas, the largest hyaenodon, was the size of a small rhinoceros, and was probably a solitary nocturnal predator.  This matches the description of Amarok perfectly.  Furthermore, H. gigas would have had a thick coat to survive the ice age, and could easily have tolerated modern day climate of the Inuit's home range in the Arctic.

Moving farther south and east, Canada's Northwest Territories are home to the Waheela, the Amarok's southern cousin.  One cryptozoologist Ivan Sanderson believes that the Waheela represents a leftover pocket population of Amphycyonidae or bear dogs, which went extinct about 1.8 million years ago.  (Not having read Sanderson's book, I can't imagine why he fingered the Amphycyonidae instead of dire wolves, since dire wolves are practically contemporary.)

And more southerly still we have the Shunka Warakin, which is a large wolf like animal which is a member of Native American folklore, specific to the central states and the Rocky Mountains.  The Shunka Warakin is apparently part of Sioux culture, and according to cryptozoologist Lorne Coleman the name translates to "the one who carries off dogs."

Several Shunka Warakin candidates have surfaced over the years, but all have been debunked eventually.  Most recently, an unusually large wolf was said to be responsible for the deaths of 120 sheep over the course of one year in Montana.  (The proof on this claim is somewhat lacking, and knowing ranchers and humans in general as I do, I rather suspect that every sheep which died in that time was chalked up to this one particular naughty wolf.  But I digress.) 

Eventually the wolf was shot, and was identified by Montana Fish and Game officials as being a regular wolf with an unusual reddish coloration.