Watersnakes are largely ignored by herptoculturists, and I’ve never quite understood why. Hardy, prolific, and often colorful, their utilization of two habitats makes for very interesting observations. Today I’d like to focus on the northern watersnake (Nerodia sipedon sipedon), and to mention a few others.
Background color varies through shades of pale gray to dark brown, with reddish to black cross-bands. Juveniles are brightly marked, while the colors of older animals usually darken. Stoutly built, the northern watersnake may reach 4 ½ feet in length, but averages 3 feet.This species interbreeds with its subspecies, the midland water snake, which may confuse identification at range overlaps.
The range extends from southeastern Quebec, Canada to North Carolina, Alabama and Mississippi. Related subspecies occur as far west as Colorado.
The endangered Lake Erie water snake (N. s. insularis), a subspecies of the northern, is found only along Put-In-Bay, Lake Erie.
The northern water snake frequents swamps, ponds, lakes, rivers and streams. It rarely strays far from the water’s edge, but frequently basks on logs and overhanging branches. Although preferring quiet waters, I sometimes encounter them along swiftly flowing rivers.
Status in the Wild
This snake can build up large populations in suitable habitat but, in my experience, does not adjust well to human presence (it is sometimes killed in the mistaken belief that it is venomous and reduces game fish numbers).
Several years ago I visited formerly well-populated ponds on Long Island, NY, as part of a government-sponsored survey. Despite adequate habitat and a healthy prey base, I found nearly all to be barren of snakes, and local fishermen confirmed their absence.
Watersnakes seem almost “crazed” when food is scented. Legendary reptile man Raymond Ditmars reported catching them on fishes tied to a string, a feat I repeated a half-century later with admirable results. I have also taken them in minnow traps.
Watersnakes feed upon a wide variety of frogs, tadpoles, salamanders and fishes and crayfishes.
Mating occurs in early spring. The young, 9-100 in number, are born alive after a gestation period of 2-3 months (March-July).
This snake was once common within NYC but has declined dramatically. I re-introduced it to the grounds of the Bronx Zoo in 1986, and a small breeding population is now to be found there.
Northern water snakes are harmless but aggressive when disturbed, and are often mistaken for the venomous water moccasin. The confusion is greatest in the Southeastern USA, a watersnake-lovers paradise, home to 12-15 subspecies. The massive Florida green water snake (N. floridana) reaches 6 feet in length and even holds its mouth open when threatened, in a manner reminiscent of the moccasin’s display.
Various watersnake species regularly hybridize, producing a bewildering array of forms in the species-rich southeast. Despite the passage of over 20 years, I still clearly recall a gorgeously-patterned individual that I narrowly missed capturing in south Florida. It was almost certainly a mangrove watersnake (N. clarkii compressicauda), perhaps hybridized with a Gulf salt marsh or Florida watersnake. I realize that my awe seems odd in these times of captive-bred “designer snakes”, but to encounter such a creature in the wild was quite a thrill.
You can learn more about the natural history of the 10 Nerodia species at http://www.jcvi.org/reptiles/search.php?submit=Search&exact%5B%5D=genus&genus=Nerodia.
Nerodia sipedon image referenced from Wikipedia and originally posted by Brian Gratwicke
Nerodia rhombifer image referenced from Wikipedia and originally posted by LA Dawson.