Dr Gill said an early part of the film clearly shows the little bear almost reaching the top of the slope where his mother is waiting, the Daily Mail reports.
Some have tweeted about their concern the drone may have spooked the bears, thinking it was a bird of prey.
Towards the end of the footage when the cub looks like he has made it, the drone swoops in and the mother bear appears to frantically swipe to grab her cub.
But instead of helping the youngster, she ends up dislodging the snow around it and sends it tumbling further than ever.
Mark Ditmer, a scientist at Boise State University, Idaho, claimed the drone may have disturbed the animals.
"The bears were extremely disturbed by what definitely appears to me – based on the way it's moving – a drone capturing a video," he said.
The bear video, captured on on June 19, was originally shared on YouTube, and then posted on Twitter and Facebook by Ziya Tong, of the Royal Canadian Geographical Society.
The TV presenter said she was trying to highlight poor drone usage, despite originally presenting the video as a motivational one.
Tong originally said: "We could all learn a lesson from this baby bear: Look up and don't give up".
The cub is seen coming agonisingly close to reaching the top, but suddenly loses its grip and plummets back down in a matter of seconds. As they traverse the snowy face, the cub loses its footing and slips down, trying to cling on with his small paws.
It seems to manage to gain some traction only to plunge down further, but he seems more energetic than ever as he climbs back up.
Eventually the cub manages to find better footing on the track already cut by his mother and gets to the top.
"I was stressed watching this," wrote one person on Twitter.
Another added: "I couldn't take it .. I had to fast forward just to make sure he made it."
Another joked: "This is almost giving me lion king flashbacks."
Others commented that the bear's struggle was motivational.
"We could all learn a lesson from this baby bear: Look up & don't give up."
Others commented on the mother bear's parenting skills, with some commending her – and others suggesting they may be why she only has one cub.
"Parents could learn a lesson from mama bear: Sometimes you've got to let kids figure it out on their own even if they slip and struggle a little," wrote one Twitter user.
Urban areas – including major world cities such as Paris – have banned drones because of the threats they pose to humans.
But their use in countryside is largely unregulated.
