Lake Erie Watersnake

Characteristics

The Lake Erie watersnake (Nerodia sipedon insularum), a subspecies of the common watersnake (N. sipedon), varies in colour, but many individuals are brown or dark brown with faint alternating dark (sometimes reddish) horizontal banding on the back and sides (exactly the same as in the northern watersnake). Some, however, are more of a slate grey colour and the banding can range from very faint to pronounced. The belly is normally light yellow to grey. The scales of this species are keeled (ridged down the centre), which gives the snake a rough, rather than a shiny, appearance.

Lake Erie watersnake © Joe Crowley

Similar Species

Many of the species that can be confused with the northern watersnake are not present on the Lake Erie Islands where this species is found. It may be mistaken for the eastern foxsnake, blue racer or melanistic gartersnake. The eastern foxsnake has a yellow to light brown body with brown blotches down its back and two alternating rows of smaller blotches along the sides. The blue racer is blue or blueish green and has smooth scales. The melanistic gartersnake is much smaller than the Lake Erie watersnake and has a black back with no patterning. Lake Erie watersnakes are found along the shorelines of the western Lake Erie islands they inhabit, whereas the blue racer occurs in interior savannah habitat. Juveniles of these and other species look very similar and can be very difficult to differentiate.

Lake Erie watersnake © Joe Crowley

Habitat

The Lake Erie watersnake is found along the shorelines of Pelee and other western Lake Erie islands. These snakes use the dolomite and limestone rocks, ledges and crevices along the shoreline for basking and hiding, and are rarely found far from these rocky shoreline habitats. They can also be found in sandy areas, where logs, debris and vegetation provide cover. The Lake Erie watersnake hibernates inland in underground dens, crevices and burrows, hollow logs or rock piles.

View an interactive map of the known ranges of Lake Erie watersnakes in Ontario.

The Lake Erie watersnake is covered in the Ontario Reptile and Amphibian Atlas publication

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Beaver River, Uxbridge © Sean Marshall

Biology

Lake Erie watersnakes reach sexual maturity at three to four years of age. This species can live up to 12 years in the wild. It breeds from late May to late June after emerging from hibernation. Females develop the eggs within their bodies and give birth to live young in late summer or early autumn. On average, females have 23 young, but the litter size can range from nine to 50!

The Lake Erie watersnake eats fish, which it catches along the shoreline ofthe Lake Erie islands. The round goby was introduced into Lake Erie and has become the primary prey of this species. It is an excellent swimmer and can be found up to seven metres below the surface of the water. It rarely swims more than 50 metres from shore, but is capable of long-distance dispersal, and individuals have been documented travelling tens of kilometres between islands and mainland sites. Although the Lake Erie watersnake usually swallows small prey head first upon capture, it may carry large fish to shore before consuming them.

Like the northern watersnake, the Lake Erie watersnake is curious and not as wary of humans as many other snakes are. It may even approach swimmers as it investigates the source of ripples in the water (which could be from a fish or other prey) or if it mistakes them for a floating log or other debris it can hide in or bask on. Lake Erie watersnakes are harmless but will bite in self-defence if they are captured. Although often their bite is not even felt, it can cause mild bleeding because the snake’s saliva contains an anticoagulant.

Other names: Natrix sipedon insularum

Juvenile Lake Erie watersnake © Joe Crowley

Threats and Trends

The Lake Erie watersnake continues to decline in Ontario. It is severely threatened by habitat destruction resulting from the development of cottages and homes along the shoreline. Shoreline alteration, such as the construction of barrier walls or conversion of rocky shorelines to lawns and beaches, also destroys the natural habitat on which this species relies. Despite significant local education efforts and the knowledge that this species is not venomous, human persecution is still a serious threat to it on Pelee Island. Road mortality and predation also threaten the Lake Erie watersnake, especially on Pelee Island.

Current Status and Protection

The Lake Erie watersnake is currently listed as Special Concern under the Ontario Endangered Species Act, 2007 and the federal Species at Risk Act. The species has also been designated as a Specially Protected Reptile under the Ontario Fish and Wildlife Conservation Act. These acts offer some protection to individuals and their habitat. The International Union for Conservation of Nature has not yet assessed the global status of the Lake Erie watersnake, but lists the common watersnake (of which the Lake Erie watersnake is a subspecies) as Least Concern. The common watersnake’s status was last confirmed March 2007.

Learn more about reptile and amphibian conservation and what you can do to help these species on our Reptile and Amphibian Stewardship page.

What You Can Do

Report a sighting
Get involved in reptile and amphibian conservation on your property, on the road and in your community
Donate to support reptile and amphibian conservation
Watch for reptiles and amphibians on the road
Don’t release pet reptiles and amphibians into the wild
Read more about the Lake Erie watersnake in the Ontario Reptile and Amphibians Atlas publication.