1. I know enough about bears that while one could stand on it's hind legs, they aren't bipedal and could not possibly run like that, much less with the speed the creature I saw moved.
2. We saw this thing clearly, it was exactly like what has classically been described as "bigfoot". Tall, large, furry, like a humanoid ape. I saw it's face.

There was a famous bear who walked upright on the island due to injury if you're referencing that yeah.