Video from Katmai National Park and Preserve in Alaska shows an enormous brown bear moving through a river on its hind legs while watching the water for salmon. Originally posted to Instagram by Sean Mcdermott (@seantheemcd), and shared on Reddit to great fanfare last week, the moment looks almost human. What happened? In the footage, the bear casually strolls through a river on its hind legs, like it's just out for a nice walk. The scene was ca…