Species Profile

Timber Rattlesnake

Scientific Name: Crotalus horridus
Taxonomy Group: Reptiles
COSEWIC Range: Ontario
COSEWIC Assessment Date and Status Change: November 2010
COSEWIC Status: Extirpated
COSEWIC Status Criteria:
COSEWIC Reason for Designation:
COSEWIC History of Status Designation: Designated Extirpated in May 2001. Status re-examined and confirmed in November 2010.
SARA Status: Schedule 1, Extirpated
Date of Listing (yyyy-mm-dd): 2003-06-05

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Quick Links: | Photo | Description | Habitat | Biology | Reasons for extirpation | Protection | Recovery Initiatives | National Recovery Program | Documents

Image of Timber Rattlesnake

Timber Rattlesnake Photo 1



The Timber Rattlesnake is a large, venomous snake. It is yellow, brown or black, with dark brown or black V-shaped crossbands on the back. The head is somewhat triangular, and eyes have vertically elliptical pupils.


Distribution and Population

Historically, the species was found throughout the eastern United States and in Ontario. It is no longer present in Maine and Rhode Island, and has not been seen in Canada since 1941, when a specimen was collected from the Niagara Gorge. It has not been found anywhere else in Canada since then, and is therefore considered extirpated from Canada.



The preferred habitats for Timber Rattlesnakes in the northern parts of their range are forested areas with rocky outcrops for denning and basking. Granitic escarpments and ledges with accumulations of talus (rock debris) are common characteristics of the communal den within which the snakes hibernate.



The diet of the Timber Rattlesnake is comprised almost exclusively of small mammals. Gravid (pregnant) females do not feed, and select different habitat features than those preferred by males and non-gravid females, in particular choosing warmer sites. On average, females reproduce every three years, usually giving birth to five to nine young. Preferred body temperature is about 27?C during the active season, falling to a minimum of 4.3?C during hibernation.


Reasons for extirpation

Intrinsic characteristics of the species, such as delayed maturity, low reproductive output, and low juvenile survivorship, combined with the effects of human exploitation through bounty hunting, commercial collecting and sport hunting, have led to the species’ extirpation from Canada. Habitat destruction and scattered distribution of suitable hibernacula were other limiting factors. The colonial nature of the species made it particularly vulnerable to human persecution, which has had devastating consequences on populations of the Timber Rattlesnake.



Federal Protection

The Timber Rattlesnake 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.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.


Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Timber Rattlesnake (Crotalus horridus) in Canada
Status Final posting on SAR registry


Recovery Progress and Activities

Summary of Progress to Date A draft recovery strategy has been created for the Timber Rattlesnake. Information was compiled concerning the possible causes of the species extirpation from Canada. Former range extent and population areas were described using verified historical information. A review of the available scientific literature was conducted which included other known population sizes and their viability, spatial and activity patterns, specific habitat needs, including hibernation and gestation features, and foraging needs. A comparative description of historic and potentially suitable sites also was assessed. Knowledge gaps for this species have been identified. Summary of Recovery Activities Museum and library searches for specimens and information have been conducted. There have been meetings with rattlesnake experts in Canada and the United States. Also, zoos were checked for a source of genetic material.URLs Ontario’s Biodiversity: Species at Riskhttp://www.rom.on.ca/ontario/risk.php?doc_type=fact&lang=&id=102 Natural Resources Canada: Amphibians and Reptiles of Ontariowww.cfs.nrcan.gc.ca/subsite/glfc-amphibians/crotalus-horridus Canadian Biodiversity: Species:http://canadianbiodiversity.mcgill.ca/english/species/herps/herppages/Cro_hor.htm


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.

5 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Timber Rattlesnake Crotalus horridus in Canada (2011-09-09)

    The Timber Rattlesnake is a large venomous rattlesnake, characterized by yellow or brown colouring with dark brown or black V-shaped bands across the back. Adult sizes range from approximately one to two metres. The head is triangular with a distinct “neck”. As with all pit vipers, there is an opening visible between the eye and the nostril. Males are much longer and heavier than the females. Timber Rattlesnakes can be confused with Massasauga rattlesnakes and some non-venomous species, such as the fox snake. All non-venomous snakes lack the facial pit of the rattlesnakes. The Massasauga rattlesnake has nine large scales on its head, whereas the Timber Rattlesnake has many small scales on its head.
  • COSEWIC Status Appraisal Summary on the Timber Rattlesnake Crotalus horridus in Canada (2011-09-09)

    Designated Extirpated in May 2001. Status re-examined and confirmed in November 2010.

Response Statements

  • Response Statement - Timber Rattlesnake (2011-12-08)

    Due to a recent change in COSEWIC procedures, reasons for status designation are not available for some species whose status is being confirmed.

Recovery Strategies

  • Recovery Strategy for the Timber Rattlesnake (Crotalus horridus) in Canada (2010-03-23)

    The timber rattlesnake (Crotalus horridus) was designated Extirpated by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 2001 and was officially listed under the Species at Risk Act (SARA) in June 2003. SARA (Section 37) requires the competent Minister to prepare a recovery strategy for all listed extirpated, endangered, or threatened species. The Canadian Wildlife Service – Ontario, Environment Canada, led the development of this recovery strategy, and it was developed in cooperation with the Government of Ontario. All responsible jurisdictions reviewed and acknowledged receipt of this strategy.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2010 - 2011 (2011-09-09)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings during the past year assessing the status or reviewing the classification of a total of 92 wildlife species.
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