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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.

COSEWIC Status: Threatened

COSSARO 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.

Conservation Actions

Do You Work Outdoors?

Range Map

Photo Gallery

Massasauga tail

Newborn Massasaugas Credit: Jeremy Rouse

Table rocks provide female Massasaugas with a safe place to incubate their young. Credit: Jeremy Rouse

For more information about the Massasauga Rattlesnake in the Georgian Bay area, contact:

Ministry of Natural Resources and Forestry
SAR Biologist
7 Bay Street
Parry Sound, Ontario
P2A 1S4
Phone: 705-746-4201

Georgian Bay Islands National Park
901 Wye Valley Road
Midland, Ontario
L4R 4K6
Phone: 705-526-9804

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