This is a yellow-bellied water snake.

Southern Missouri swamplands are a good place to find this snake. It lives on small fish, frogs and crawdads.

If you happen upon a yellow-bellied water snake, be sure it is what you think it is. It can look quite like a cottonmouth. The cottonmouth is venomous. The yellow-belly is non-venomous and considered harmless, although if cornered and aggravated it will bite you.

I do not recommend this snake be handled because it packs a punch with a stinky musk that it will smear on you as it squirms. You can tell the yellow-bellied is non-venomous by its blunt rounded nose and the round pupils in its eyes.