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Timber Rattlesnake

Status: Extirpated

Timber rattlesnake © Scott Gillingwater


The timber rattlesnake (Crotalus horridus), which has an unmarked, triangular head and vertical pupils, is heavy bodied and typically grow to 100 up to 120 centimetres in length. Generally, the body of this snake is yellow, brown or grey with dark bands, but some individuals are all black.

The unmarked dark tail has a characteristic rattle at the end, which can break off. Therefore, the absence of a rattle does not indicate that a snake is not a rattlesnake.

Timber rattlesnake © Alex Figeroa CC BY-NC-SA 2.0

Similar Species

The only other rattlesnake in eastern Canada is the Massasauga, which has dark bars on the top of the head. That species reaches a length of only 55 to 75 centimetres.

Timber rattlesnake © Amelia Argue


Timber rattlesnakes inhabit upland forested areas with associated rocky areas. This snake hibernates communally in rock slides and on ledges and outcrops, usually those that face south. Occupied sites range from mature forests to young forests.


Timber rattlesnakes breed in the spring or fall, and females give birth to an average of nine live young from August through October. Females reproduce only once every two to six years. At birth, the young are 19 to 38 centimetres in length. Females reach maturity after seven to 13 years when they are usually longer than one metre in length. The timber rattlesnake is a long-lived species, and some individuals are thought to live for over 30 years. Individuals return to the same hibernation site year after year. In the summer, these snakes move many kilometres away from their hibernation site to search for food and mates.

Like all rattlesnakes, the timber rattlesnake is a pit viper. Two heat-sensitive pits between its eyes and nostrils allow it to see thermal images of its environment. This ability, along with its venom and camouflage, make the timber rattlesnake a very effective ambush predator of small mammals, its primary prey. This snake uses its fangs to deliver venom produced in special glands behind its eyes. Although the timber rattlesnake is venomous, few human fatalities due to its bite have been recorded. More people die every year from insect stings than from rattlesnake bites.

Timber rattlesnake © Scott Gillingwater

Threats and Trends

This species no longer occurs in Ontario, likely because of human persecution and habitat loss. In the 19th century, hunting parties would attack overwintering sites and kill all the snakes found. The last confirmed report of a timber rattlesnake from Ontario was in 1941.

Timber rattlesnake © Ryan Wolfe

Current Status and Protection

The timber rattlesnake is currently listed as Extirpated under the Ontario Endangered Species Act, 2007 and Extirpated under the federal Species at Risk Act. It is not listed as a Specially Protected Reptile under the Ontario Fish and Wildlife Conservation Act. The International Union for Conservation of Nature lists the status of the timber rattlesnake as Least Concern. The species’ status was last confirmed in 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.

Timber rattlesnake © Ryan Wolfe

What You Can Do

Timber rattlesnake © Ryan Wolfe