Gray Ratsnake Carolinian population
Scientific Name: Pantherophis spiloides
Other/Previous Names: Eastern Ratsnake (Carolinian population)
Taxonomy Group: Reptiles
Last COSEWIC Assessment: April 2007
Last COSEWIC Designation: Endangered
SARA Status: Schedule 1, Endangered
Image of Gray Ratsnake
The Gray Ratsnake (Elaphe spiloides) is the largest snake in Canada, reaching a maximum snout-vent length (SVL) of approximately 190 cm. The colour pattern of adult Eastern Ratsnakes is widely variable across the species’ range. Throughout all populations in Canada, adult Gray Ratsnakes are typically plain, shiny black with white, yellow, orange or red colouration on the skin between the scales. The ventral surface is typically white or yellowish with a clouded grey or brown pattern, often resulting in a checkerboard appearance. Ratsnakes can often be distinguished from other snakes by their throat, which has a plain white or cream colour. In contrast to adults, juveniles are dorsally patterned with dark grey or brown blotches on a pale grey background. (Updated 2017/05/24)
Distribution and Population
The Gray Ratsnake is widely distributed and commonly found throughout the forested areas of the eastern and central United States. However, within Canada, the Gray Ratsnake is confined to two geographically disjunct regions in southwestern (Carolinian Faunal Province) and southeastern (Great Lakes/St. Lawrence Faunal Province) Ontario. In this report, populations from these two regions will be treated as two Designatable Units referred to as the Carolinian and Great Lakes/St. Lawrence populations. In southwestern Ontario, the Carolinian population is associated with the Carolinian forest along the northern edge of Lake Erie and is limited to four very small, isolated populations in Middlesex, Elgin, Haldimand-Norfolk and Niagara counties. The Great Lakes/St. Lawrence population is associated with the Frontenac Axis in Frontenac, Lanark, and Leeds and Grenville counties. (Updated 2017/05/24)
The Gray Ratsnake is semi-arboreal and typically found in a wide variety of woodland habitats across its range. At the home range scale, they seem to prefer a mosaic of forest and open habitat (fields; bedrock outcrops) with a high amount of edge. Detailed studies of habitat use on the Frontenac Axis have established that ratsnakes require a variety of habitat types throughout their life cycle. In winter, ratsnakes hibernate below ground in communal hibernacula that provide shelter from both freezing temperatures and dehydration. During the active season, individuals seek shelter in standing snags, hollow logs, rock crevices and under rocks to avoid high temperatures and predators. Females nest in decaying matter inside standing snags, stumps, logs and compost piles where conditions are humid and temperatures are approximately 30ºC. (Updated 2017/05/24)
Gray Ratsnakes reach maturity in approximately 7-9 years. Once sexually mature, females produce a clutch of 8-15 eggs every 2-3 years. In Ontario, females nest in early July to early August, approximately one month after the mating season, which spans from late May to early June. The eggs hatch between late August and late September following an incubation period of around 60 days. The harsh climate in Canada restricts the active season of ratsnakes to approximately 5 months (May – October). During this active season, ratsnakes have relatively large home ranges (~18 ha) and disperse as far as 4 km from their hibernacula. Adults demonstrate strong site fidelity by often using the same home range locations both within and between years. Gray Ratsnakes are both predators and prey of numerous species. They feed mainly on small mammals (~65%) and birds (~30%) and known predators include a number of large birds of prey (e.g. red shouldered hawk (Buteo lineatus), osprey (Pandion haliaetus), red tailed hawk (Buteo jamaicensis)) and medium-sized mammals (e.g. fisher (Martes pennanti), mink (Mustela vison)). (Updated 2017/05/24)
Life-history characteristics such as biennial reproduction, delayed age at maturity (~7 years) and slow growth rates make Canadian populations of Gray Ratsnakes particularly sensitive to disturbances. Mortality caused by increased contact with humans (e.g. road mortality, destruction of hibernacula, deliberate killing of ratsnakes by people) can therefore have significant impacts on populations. Furthermore, the suitable habitat in the Carolinian region is severely restricted and heavily fragmented, and it is unknown whether enough habitat remains to support viable populations of ratsnakes. Suitable habitat on the Frontenac Axis is much more abundant, but increased recreational activity in the area has led to increased development and will likely reduce and fragment the existing habitat. (Updated 2017/05/24)
Federal ProtectionThe Gray Ratsnake, Carolinian population, is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
In Ontario, this species is protected under Ontario’s Fish and Wildlife Conservation Act, 1997.
Provincial and Territorial Protection
Status of Recovery Planning
Recovery Strategies :
Name Recovery Strategy for the Gray Ratsnake (Pantherophis spiloides), Carolinian and Great Lakes/St. Lawrence populations, in Canada
Status First posting on SAR registry
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
10 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- COSEWIC Assessments (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Recovery Strategies (1 record(s) found.)
- Orders (3 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Consultation Documents (1 record(s) found.)
- Recovery Document Posting Plans (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
COSEWIC Annual Report - 2007 (2007)2007 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
Recovery Document Posting Plans
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