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Massasauga Rattlesnake

Sistrurus catenatus catenatus

It is the only venomous snake species in Ontario, and although its venom is potent, this is a small snake with small fangs and a limited amount of venom. Snake bites are rare; approximately 2-3 per year and with treatment, a full recovery is highly probable.

If you see or hear a rattlesnake, simply leave it alone! If you give the snake room it will retreat.

Species at Risk Status

Federal Government status: Threatened

Provincial Government status: Threatened


  • Medium-sized snake (50 to 76 cm.) with a thick body.
  • Thick tail does not taper to a point and ends with a distinct segmented rattle. Rattle segments are added when the snake sheds its skin.
  • Neck is narrow in contrast with the wide head and body.
  • Bow-tie shaped dark brown blotches along back with two or three rows of spots along sides, grey background colour, dark belly.
  • Dark lines extend from eyes to neck, vertical pupils (cat-like), heat sensitive pits between nostril and eye.
  • May live in captivity for up to 20 years.


  • Small mammals including voles, mice and shrews.

Habits and Reproduction

  • Hibernates below the frost line from October to mid-April. A rock fracture, root pocket or rodent burrow provides a suitable site. In eastern Georgian Bay, these sites are often associated with damp areas or wetlands.
  • Emerge from hibernation in late April.
  • Uses venom to subdue prey.
  • Shy, secretive, non-aggressive snake. Relies on camouflage and remaining still to avoid predators.
  • Heat sensitive pits on head allow it to sense warmth in the vicinity while hunting under the cover of darkness.
  • They reach sexual maturity at age 4 or 5 and mate mid to late summer.
  • A female may reproduce every 2nd or 3rd year. Pregnant females will seek out “gestation” sites. These sites provide safe cover and a good range of temperatures so they can incubate their young. In our area, “table” rocks are often the preferred sites and a female will return to the same site each time she is pregnant.
  • The average litter is 12, and the young are born usually in August.
  • Newborns are 20-25 cm long and similar to adults but lighter in background colour. Their rattle is yellowish in colour. The fangs and venom are present at birth.


  • Found in rocky scrub habitat, damp lowlands, open woodlands, bogs, and fens.


  • Habitat loss particularly of important habitat such as hibernation sites, road mortality and direct persecution are the greatest threats to this snake.

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