Don't apply ice, don't fashion a tourniquet, and never attempt to cut or suck the venom out.
The zoo is busting myths about how to safely treat a bite wound while raising awareness about the endangered species.
Native to the Georgian Bay and Bruce Peninsula regions, the massasauga rattlesnake is docile and avoids people, relying on its dusty camouflage-patterned skin to avoid detection.
The massasauga also has relatively small teeth that can't penetrate leather-hiking boots or loose clothing.
But don't be mistaken, says Andrew Lentini, a Toronto Zoo keeper in the reptile department. When they do bite, he says, it can be painful.
Only about a quarter of all rattlesnake bites are "dry" — meaning non-venomous — so it's best to treat any bite as a medical emergency.
"Not going to sugar coat it, left untreated it could be quite serious," said Lentini.
Once bitten, people have about an hour to get medical treatment. But moving around too much can make it worse — it spreads the venom — so Lentini advises immobilizing the affected extremity and getting someone to carry you to safety.
Rattlesnakes won't bite unless provoked. Hikers need to be aware of stepping on them and never attempt to pick one up.
"Snakes need plenty of space," Lentini cautions.