Bears are known for their intelligence, strong memories and physical capacity. And above everything, they can be very, very scary.
Here is a video making it evident. A rafting group on the Elaho River in British Columbia, Canada, was left afraid when they saw a grizzly bear, a breed which is generally known to be defensive but at times unpredictable, plunging into the water of the river and charging towards at one of the kayakers who was going ahead of them.
The adventure group members shouted and whistled to raise an alarm over the bear's arrival. However, the kayaker eventually gets off the animal's path and it was seen running towards the other bank of the river.
The trailing rafters heaved a sigh of relief as nothing untoward happened.
It is often said that to avoid a bear attack, it is wiser to lie dead instead of running as that will not succeed against the animal which has a good speed. Running in front of the bear gives it an impression that its prey is before it and it remains in pursuit. By lying dead, one gives impression to the bear that he/she is not a threat to its life and hence ensures his/her own safety.