Fast facts
Common name: Northern watersnake
Scientific name: Nerodia sipedon
Range in MA: Statewide except Dukes County
Conservation status: Common, not listed
Fun fact: Ovoviviparous (mothers carry eggs inside their bodies and give birth to live young).
Similar species: Sometimes confused with venomous "water moccasins" or cottonmouths, which do not live in or near Massachusetts and can be found no further north than Virginia.
Description
Northern watersnakes have heavily-keeled scales and grow relatively large. Coloring can vary widely between brown, gray, reddish, or brownish-black. Bands tend to break up into alternating blotches towards their tails and tend to be wider on their backs and narrower on their sides. As they age, their colors can darken, with some becoming almost completely black. Bellies are pale and marked with small black or reddish-orange crescents. Adults range in length from 24–50+ inches.
Habitat
Northern watersnakes live around the borders of almost every wetland habitat in the state, from mountain streams to salt marshes. They often bask along shorelines on exposed rocks, limbs, bridge abutments, or beaver lodges. They appear in near-shore areas to hunt for frogs and fish.
Life history
Mating takes place in May and June. Females give birth to up to several dozen young from August to early October. Northern watersnakes are excellent swimmers and can feed both above and below the surface. They mainly eat fish and amphibians but can also take small mammals, birds, crayfish, and insects. They are neither venomous nor dangerous to people, and they will not attempt to bite unless they believe they are cornered or under attack. Their normal behavior when approached is to dive underwater and disappear.