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Overhead view of eastern massasauga
rattlesnake’s relatively wide head.

Side-view of eastern massasauga
rattlesnake’s head, showing heat
sensitive pit between eye and nostril.


Worldwide, there are approximately 290 species in the pit viper family, but only
three occur in Canada:
  • northern pacific rattlesnake (Crotalus viridis oreganus) from south-central
    British Columbia;
  • prairie rattlesnake (Crotalus viridis viridis) from southeastern Alberta and
    southwestern Saskatchewan;
  • eastern massasauga rattlesnake (Sistrurus catenatus catenatus) from Ontario.

A second pit viper was once present in Ontario, the timber rattlesnake (Crotalus horridus). Habitat loss and human persecution are thought to have caused its extirpation from Ontario. The last known sighting is from 1941 near Niagara. This species is now only present in the U.S., where it is in decline.

The eastern massasauga rattlesnake possesses a long, slender and forked tongue which, when not extended, is housed within a sheath inside the snake’s mouth. With a flick of its tongue, the snake gathers information about its surroundings. Sampling the air allows the snake to retrieve scent molecules, which it then transfers to its “vomero-nasal organ” (Jacobson’s organ), located in the roof of its mouth. By interpreting the information gathered by the nerves within this organ, the snake learns about its surroundings.

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