Northern water snakes eat mostly fish and amphibians, including minnows, tadpoles, frogs, and salamanders, and they are not venomous.
What Northern Water Snakes Eat
These common snakes of ponds, lakes, and slow rivers hunt in and around the water. By day they search plants at the water’s edge for small fish, tadpoles, frogs, salamanders, crayfish, worms, and insects. At night they focus on minnows and other small fish resting in shallow water. They will occasionally take turtles, small birds, and mammals. They hunt mainly by smell and sight.
Water Snake or Cottonmouth?
Water snakes are often killed because they are mistaken for venomous cottonmouths. A few differences help:
- Water snake: slimmer body, head not much wider than the neck, round pupils, no heat-sensing pits.
- Cottonmouth: thick body, wide wedge-shaped head, cat-like pupils, and a pit between eye and nostril.
If you cannot tell, keep your distance. Never try to kill a snake, since that is when most bites happen.
Bites and Safety
Water snakes are not venomous, but they defend themselves hard if cornered, and a bite can bleed freely because their saliva has a mild anticoagulant. Wash the wound with soap and water and see a doctor if it looks infected.
Pet Ponds
A water snake near a backyard pond may snack on small fish or frogs. Provide hiding spots for fish, such as plants and rocks, and the snake will usually move on.
Bottom Line
Northern water snakes are harmless fish and frog hunters that play a useful role in aquatic ecosystems. Compare with garter snake diets, what rat snakes eat, and what viper snakes eat.
