Water snake
Introduction
Water snakes (Nerodia spp.) belong to a family of non-venomous colubrid snakes found in North America. In the south-eastern USA water snakes are among the most abundant, and most often encountered reptiles. Although they are not venomous they will defend themselves and bite if necessary. Some water snakes are known to display aggressive behavior. Water snakes that belongs to other groups than Nerodia are not described here.
A full table of the type below can be found on the page about the different water snake species or as a pdf here.
Water snakes can climb and they are often resting on branches above the water. When disturbed they will drop into the water - sometimes into boats passing by.
The saliva of the Northern Water Snake contains a compound inhibiting the coagulation of blood - so a bite from a water snake can cause some bleeding. However, Water Snakes are not lethal in any way. Water snakes also have scent glands near the base of their tails (in their cloaca) from which they can excrete an ill smelling musk.
Water snakes are foraging in the water edge looking for small fish - preferably the slow moving fish (Linzey & Clifford, 2002)1 - and other animals in the shallow water. They eat small fish, reptiles, frogs, worms and small birds and mammals. All Water Snakes eat their prey alive. Until water snakes reach a certain size they main prey is small fish and other small animals found in the water. Frogs and birds are captured by larger individuals. According to a study2 (Mushinsky et al. 1982) there is a shift in prey choice towards frogs and other larger animals when the snakes reaches a length of about 1.5 feet. Though, a water snake less than 1.5 feet will probably not eat many frogs or other larger animals (ibid).
Some of the species of the genus Nerodia that is described on this webpage includes:
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A Northern Water Snake Broadbanded Water Snake |
Diet
The diet of water snakes is principally composed of fish, but frogs, salamanders and frog tadpoles are also commonly found in stomachs of water snakes upon dissection. A study by King (1939)3 showed that 35% of a population of water snakes had tadpoles and salamanders in their stomachs, besides all other types of prey.
Hunting in water
Water snakes weaves around in shallow waters with its mouth open waiting for any prey to come close by - within a few inches - so it can close its jaws around the prey. It also moves around on the underwater surface looking for prey in rook crevices and other hiding places (Drummond, 1983)4. Water snakes are foraging both day and night.
They have a compound in their saliva inhibiting coagulation of blood. The advantage from having an anti-clotting compound in its saliva is that when prey escapes it will leave a trail of blood that the water snake can follow.
Life cycle
Water snakes mature when they are 2 to 3 years old. Mating takes place in the spring and snakes are born between August and October. Water snakes give birth to live snakes. The eggs hatch within the female body before the birth. Litters of about 20 snakes are common and the newborn snakes have a length of 8-12 inches on average.
Northern Water Snake
The Northern Water Snake (Nerodia sipedon) is found in many different types of freshwater habitats. It can be found near large rivers and small ponds as well. When conditions are good these snakes can be found in very high numbers. Its a relatively large snake with adult females reaching a length of almost 5 feet.
They can reach an age of approx. 7-8 years. Their litters have a size of anywhere from 10 to 40 snakes and new snakes are born during late summer and early fall. It is mainly feeding on fish and fish probably constitutes about 50% of its varied diet. Larger individuals also eat a lot of frogs while smaller individuals eat anything from invertebrates to small mammals.
Because of its vicious temperament the Northern Water Snake, as well as other Water Snakes, are not suitable for keeping as pets. As the Northern Water Snake is fairly common and share some similarities with the venomous cottonmouth snake, many are killed on the suspicion on being cottonmouths.
Resources
1 Linzey, D.W., Clifford, M.J., Snakes of Virginia (2002)
2 Mushinsky, H.R., Hebrard, J.J., Vodopic, D.S. Ontogeny of Water Snake Foraging Ecology.
Ecology, 63(6) pp. 1624-1629 (1982)
3 King, W., A survey of the herpetology of the Great Smoky Mountains National Park, Amer. Midi. Nat. 21, pp. 531-582 (1939)
4 Drummond, H., Aquatic Foraging in Garter Snakes: A Comparison of Specialists and Generalists, Behaviour, Vol. 86 (1/2) pp. 1-30 (1983).