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Lake Erie Watersnake

Nerodia sipedon insularum

Family: Colubridae

The Lake Erie Watersnake is a subspecies of the Common Watersnake (Nerodia sipedon.

COSEWIC status:
  • Special Concern
SARA status:
  • Endangered
IUCN status:
  • Not Assessed

Description

The Lake Erie Watersnake 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 lighter in colour, often white or tan with dark red, tan or brown crescent-shaped spots. The scales of this species are keeled (ridged down the centre), which gives the snake a rough, rather than a shiny, appearance. Females are larger than males and can grow to over a metre in length, but most are smaller than that.

Similar Species

The Lake Erie Watersnake may be mistaken for the Northern Watersnake, Eastern Foxsnake, Blue Racer or a melanistic Eastern Gartersnake. The adult 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. Blue Racers have smooth scales and adults are tan to grey/blue. Melanistic gartersnakes have a black back with no patterning and a white or black belly. Juvenile foxsnakes and racers generally have a grey background colour with dark brown to red spots, instead of the bands that are often seen on young Lake Erie Watersnakes. As its name implies, the Lake Erie Watersnake is restricted to the shorelines of the western Lake Erie islands and its range does not overlap with that of the Northern Watersnake.

Distribution

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In Canada, the Lake Erie Watersnake is found on Pelee, Hen, East Sister and Middle islands in Lake Erie. Globally, this subspecies is limited to the southern shoreline of Lake Erie in Ohio and the remaining western Lake Erie islands.

Habitat

The Lake Erie Watersnake primarily forages offshore in Lake Erie and uses the dolomite and limestone rocks, ledges and crevices along the shoreline for basking and hiding. This species hibernates inland below the frost line in rock crevices, mammal burrows or rock piles. Lake Erie Watersnakes are typically restricted to shoreline habitats during the active season.

Biology

Male Lake Erie Watersnakes reach sexual maturity at two years of age, females at three. Females typically reproduce each year and this species can live over 10 years in the wild. This species breeds in May and June and females give birth to 13–46 (average of 27) live young in late summer or early fall. The Lake Erie Watersnake eats fish, which it catches along the shoreline of the Lake Erie islands. The Round Goby, a European species accidentally introduced into Lake Erie and the rest of the Great Lakes, has become the primary prey of this endangered species, paradoxically aiding its recovery. The Lake Erie Watersnake is an excellent swimmer and may forage up to 3 m below the surface of the water, but it rarely swims more than 50 m from shore. 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. Lake Erie Watersnakes are harmless but will bite in self-defence if they are captured. The bite can cause mild bleeding because the snake’s saliva contains an anticoagulant.

Threats

The Lake Erie Watersnake 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. Road mortality and predation also threaten the Lake Erie Watersnake.

Additional Information About This Species In Canada