Out of pure curiosity, how much constitution do you need to swim across an average river and not drown?
On the unrelated topic, what's wrong with bears lately? If memory serves me well, only a month or so ago they were lumbering, unrelenting behemots; even a river couldn't quench their primeval bloodlust.
Now, for every rock I sling at them from the relative safety of my boat they perform the same undecisive routine: first, they scamper away into the woods, then, after reaching the combat-ending distance, they turn back and attempt to maul me some more.
It's a sure sign of trouble in a species' collective psyche when everyone starts to act like a teenage girl in the mall!