DENVER (REUTERS) - A video of an unfazed, fluffy house cat staring down a large mountain lion as the predator paws at a Colorado kitchen window has gone viral, receiving nearly a million views on YouTube in just a couple of days.

The footage, recorded at a home in the Rocky Mountains about 16km west of Boulder, shows the cat sitting on the windowsill and meowing as the much-bigger mountain lion looks into the house, its eyes glinting gold in the light.

The video was posted on Sunday and by mid-morning on Tuesday it had already been watched more than 945,000 times.

It was filmed by Tom Mabe, a Louisville, Kentucky-based comedian who says the stand-off came during a visit his family made about a month ago to friends in Colorado.

In the video, the mountain lion repeatedly paws at the window as Mabe can be heard calling his wife to see.

"Is that crazy or what?" he says.

His wife can be heard asking where the kids are, and Mabe jokes that they are "out back," before reassuring her that they are still in bed.

After about 30 seconds, the mountain lion stalks away, pausing on a nearby rocky slope to gaze back at the home.

In the comments posted below the video, Mabe joked that he was hoping to get sponsorship from a double-glazing window company.

He declined to reveal exactly where the video was shot, saying that his friends are trying to sell their home.

It was the second wild animal saga to make headlines in the Boulder area this week.

On Monday, police released photos of a young female moose that wandered onto the city's main pedestrian Pearl Street shopping area, attracting a crowd of onlookers.