Nerodia sipedon
Silhouette: Beth Reinke · PhyloPic
In 3 days ~20% in a week ~40%
The common watersnake (Nerodia sipedon) is a species of large, nonvenomous, common snake in the family Colubridae. The species is native to North America. It is frequently mistaken for the venomous cottonmouth (Agkistrodon piscivorus).
Common names for N. sipedon include banded water snake, black water adder, black water snake, brown water snake, common water snake, common northern water snake, eastern water snake, North American water snake, northern banded water snake, northern water snake, spotted water snake, streaked snake, water pilot, and water snake.
The common watersnake can grow up to 135 cm (4 ft 5 in) in total length (including tail). Per one study, the average total length of females was 81.4 cm (2 ft 8 in), while that of males was 69.6 cm (2 ft 3+1⁄2 in). From known studies of this species in the wild, adult females can weigh between 159 and 408 g (5+1⁄2 and 14+1⁄2 oz) typically, while the smaller male can range from 80.8 to 151 g (2+7⁄8 to 5+3⁄8 oz). The largest females can weigh up to 560 g (20 oz) while the largest males can scale 370 g (13 oz).
N. sipedon can be brown, gray, reddish, or brownish-black. It has dark crossbands on... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 2 | Point Pelee National Park | 🇨🇦 Canada | |
| 3 | Shenandoah National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Washington | 🇺🇸 United States | |
| 2 | Baltimore | 🇺🇸 United States | |
| 3 | Philadelphia | 🇺🇸 United States | |
| 4 | Denver | 🇺🇸 United States | |
| 5 | Detroit | 🇺🇸 United States | |
| 6 | Chicago | 🇺🇸 United States | |
| 7 | Boston | 🇺🇸 United States | |
| 8 | Toronto | 🇨🇦 Canada | |
| 9 | New York City | 🇺🇸 United States |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Ecomuseum Zoo | 🇨🇦 Canada | |
| 2 | Columbus Zoo and Aquarium | 🇺🇸 United States | |
| 3 | Dickerson Park Zoo | 🇺🇸 United States | |
| 4 | Philadelphia Zoo | 🇺🇸 United States | |
| 5 | Trailside Museum & Zoo | 🇺🇸 United States | |
| 6 | Ripley's Aquarium of the Smokies | 🇺🇸 United States | |
| 7 | North Carolina Aquarium on Roanoke Island | 🇺🇸 United States | |
| 8 | Bird Kingdom | 🇨🇦 Canada | |
| 9 | Schramm Education Center | 🇺🇸 United States | |
| 10 | Belle Isle Nature Center | 🇨🇦 Canada |
With luck
About 10% of wildlife watchers report a Common Watersnake sighting in Boston on a given day, based on 53 verified sightings from GBIF citizen-science data. It is the 7th most-seen of the 10 reptiles we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
May to September
In those months about 10% of wildlife watchers report a Common Watersnake in Boston on a given day, against under 5% in October to April, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Common Watersnake sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
7th of 9
Of the 9 cities where we can rate Common Watersnake sightings, Boston ranks 7th at about 10%. The best odds are in Washington (United States, about 30%), Baltimore (United States, about 20%) and Philadelphia (United States, about 10%).
Same family: Colubridae
The closest relatives of the Common Watersnake that you can see in Boston (family Colubridae, Colubrid Snakes) are Common Garter Snake (about 20%) and DeKay's Brownsnake (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Common Watersnake is recorded against all the reptiles logged in Boston (53 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
