An easy clue on the water is that poisonous snakes swim with their lungs inflated, therefore float...non-poisonous snakes on the other hand do not and will swim with their bodies and or heads underwater.
Unfortunately, that is not quite correct. Many non-venomous snakes can swim with 1/3 to 2/3rds of their bodies near the top of the water.
Many years ago I regularly fished the area above and below the confluence of the Shenandoah and the Potomac rivers. During warm water and low water times, like in August and September, the small mouth bass were especially active and aggressive. So were a lot of swimming snakes. And, there were lots of snakes between Harper's Ferry, WV and Point of Rocks, WV/VA/MD. I'm not sure if they were aggressive or just wanting to make friends. But, I wasn't happy about their overwhelming welcomes.
A friend taught me to "whip" the snakes with my fly rod. That is, as the snakes approached me, he taught me to hit them hard, just behind the head, at about the half-length of my fly rod. It also worked with a spinning rod. It would apparently break their backs, they would sink, and they would drown.
All I know is that they would sink, and I wouldn't see them again.
I don't fish that area much anymore.
Ken
