Reptiles at Risk in Grey and Bruce Counties

Many of Ontario's reptile species only occur in the southernmost parts of the province, which has become one of the most developed regions in Canada. Widespread habitat loss, dense road networks and high population densities have caused drastic reptile declines, and some species have disappeared from many areas altogether. For example, the massasauga rattlesnake populations on the Bruce Peninsula were once continuous with those of eastern Georgian Bay. Today, these snakes no longer occur south of Wiarton.

Reptiles are characterized by delayed sexual maturity, infrequent reproduction or low reproductive success, and very high adult survival. Although this survival strategy has been successful for millions of years, it also predisposes reptile populations to rapid decline in the face of human-caused threats and makes it very difficult for populations to cope with the loss of adults. Even slight increases in annual adult mortality can cause populations to decline.

These are some of the reptile species found on Ontario Nature's nature reserves in Grey and Bruce counties:

Massasauga Rattlesnake
Massasauga rattlesnake; CREDIT: Joe Crowley

Massasauga rattlesnake (Sistrurus catenatus)
COSEWIC Status: Threatened

Despite being Ontario's only venomous snake, the massasauga is very timid and shy and avoids conflict with humans whenever possible. It relies on its cryptic camouflage to remain hidden or uses its rattle to warn others to stay away. As a result, massasauga bites are very rare and no one has died from a massasauga bite in Ontario in almost 50 years. Massasaugas can be found in a variety of habitats in Bruce County, including forest, wetlands, rocky outcrops, shorelines, fields, and scrublands. Once occurring throughout much of southern Ontario, this rattlesnake is now only found on the Bruce Peninsula, along coastal sections of eastern Georgian Bay, and in two very small populations in southwestern Ontario.

Eastern Ribbonsnake
Eastern Ribbonsnake

Eastern ribbonsnake (Thamnophis sauritus)
COSEWIC Status: Special Concern (Great Lakes population)

Associated with wetland and shoreline habitat, this snake preys predominantly on amphibians, and will disappear quickly into aquatic vegetation when disturbed. Ribbonsnakes can be differentiated from gartersnakes by their slender appearance, a distinctive white crescent in front of the eye, and the location of the lateral stripe on the 3rd and 4th scale rows rather than the 2nd and 3rd. Destruction of wetland and shoreline habitat, largely for agriculture and development, has been the primary cause of the decline of this species in Ontario.

Milk Snake
Milksnake; CREDIT: Joe Crowley

Milksnake (Lampropeltis triangulum)
COSEWIC Status: Special Concern

Milksnakes predominantly prey on rodents, and their long, thin bodies allow them to enter small cracks and tight spaces in search of food. This species' name is derived from the false belief that these snakes would steal milk from cows, because they are often seen in barns where they thrive on high densities of rodents. Milksnakes are found in a variety of habitats, including forests, fields and rocky outcrops. Although better able to cope in agricultural landscapes than most other snakes, habitat loss and road mortality have caused population declines in many areas. Their blotchy colouration and tendency to act aggressively and vibrate their tail when threatened often results in them being mistaken for rattlesnakes and killed, further adding to the threats they face in human-dominated landscapes.

Queensnake; CREDIT: Joe Crowley

Queensnake (Regina septemvittata)
COSEWIC Status: Threatened

Queensnakes are an aquatic species and inhabit rocky shorelines of rivers, lakes and marshes, where they spend much of their time under rocks. They have a very specialized diet of freshly molted crayfish and are only found in areas where this food source is abundant. In Bruce County, this species is only known to occur in a few isolated areas. This species has a dark brown back with three faint dark stripes, a yellow lateral (side) stripe, and pale yellow belly with 4 dark stripes.

Spotted Turtle
Spotted turtle; CREDIT: Joe Crowley

Spotted turtle (Clemmys guttata)
COSEWIC Status: Endangered

Spotted turtles are one of Ontario's smallest turtle species, reaching a maximum carapace length of about 12 cm. In addition to the bright yellow spots on its shell after which it is named, this turtle also has colorful orange-yellow markings on its head, neck and legs. Spotted turtles inhabit fens, bogs and other shallow water habitats in Ontario, many of which are very sensitive to water-level changes. Loss of these wetlands through building roadside ditches, intentional draining and outright destruction has led to the extirpation of populations throughout most of their range, sometimes even within protected areas. Spotted turtles now occur in small, heavily fragmented populations throughout Ontario. Illegal collection for the pet trade threatens populations whose habitat remains intact.

Snapping Turtle
Snapping turtle

Snapping turtle (Chelydra serpentina)
COSEWIC status: Special Concern

A bony-plated tail, a ridged carapace (upper shell) with a serrated back edge, and a maximum carapace length of 35-45 cm make this lumbering giant Ontario's most prehistoric-looking turtle. Its aggressive reputation is due to its defensive strategy when on land, which has evolved because it has a very small plastron (bottom shell) and cannot retreat into its shell. When in water, snapping turtles are very passive and will simply swim away if disturbed. Although once called the "common snapping turtle", this species is declining throughout much of its range as a result of road mortality, habitat loss and the unsustainable removal of adults from the wild through hunting and poaching.

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