A video purportedly showing a GoPro-captured encounter of a bear chasing a cyclist through some woods was uploaded to YouTube on 1 November 2014 with the following description:
It was a usual day, I decided to cycle in the forest and to record my walk on the Gopro. To my great surprise, I met a bear, which hardly pounced on me. Thanks God, I left alive due to the shots that thundered not far from that location!
The video was watched millions of times in the first month after it was published, but many viewers were skeptical of its authenticity. While its poster, YouTube user Mr. Gregor, did not admit to faking the video, many aspects of the footage rang false.
Let's start with the bear. The video gives only a few brief glimpses of the animal, which makes it difficult to determine if the ursine is real. But when the video is slowed down to afford a much better look at the creature, what the viewer sees is a sharp, clear image of the animal even though the background is blurred from the motion of the camera (which shouldn't be the case unless the cyclist were traveling over a relatively smooth surface at almost exactly the same speed as the bear was running):
The event depicted in the video also seems dubious. According to the U.S. Fish and Wildlife Service, grizzly bears have a top speed of nearly 40 MPH, and rangers at Yellowstone National Park have clocked grizzlies traveling at speeds in excess of 25 MPH for more than two miles. This makes it extremely unlikely a cyclist on a bumpy surface, without the aid of a declining slope, would be able to outrace a determined bear.
The end of the video also doesn't add up with what we know about bears. In the video, the cyclist gets off his bike and runs into the woods to hide behind a tree: This tactic might work if the biker were hiding from a human being, but bears hunt by smell and can detect scents from several miles away:
A black bear's sense of smell is so good that it's difficult to measure. Bears are commonly thought to have the keenest sense of smell in the animal kingdom, and estimates of the range of their sense of smell vary widely. Conservative estimates of a black bear's sense of smell state that a black bear can smell a food source from over a mile away, while other sources claim a black bear can smell food from over two miles away. A personal account from "The Great Bear Almanac" describes a black bear in California traveling "upwind three miles in a straight line to reach the carcass of a dead deer." More generous estimates place a black bear's sense of smell between 18 and20 miles, which may sound extreme, until you learn that polar bears, the black bear's cousin, have been known to follow seals for up to 40 miles.
Although this particular video of a bear chasing a cyclist may be fabricated, encounters such as the one depicted do occur. In August 2013, two cyclists were biking in Jasper National Park in the Canadian Rockies when they had a close encounter with a grizzly bear: