What type of water snake are you talking about? Is it a Banded Water Snake? A Cottonmouth? Lets go with both. Here are some of the animals that will eat these snakes. Banded Water Snakes are not venomous. They are eaten by: Birds, hawks, osprey, etc. Racoons; Opossums; Mongoose; And probably more. read more
Water snakes and water moccasins are from two different families (respectively, Colubridae, the largest snake family; and Viperidae, or vipers), but they look superficially similar, according to Bill Heyborne, a herpetologist and professor of biology at Southern Utah University. read more