Tiger Snake
The Tiger Snake is one of Australia's most dangerously venomous snakes — historically a major cause of snakebite deaths, and still capable of killing a person within hours without treatment. They are largely gone from metropolitan Sydney but remain present in the Blue Mountains, the Southern Highlands and the cooler, wetter parts of the Greater Sydney region. They are wetland specialists, closely tied to frogs and damp habitats, and they defend themselves more readily than most Sydney snakes.
The right response to finding one is to stop, back away slowly, keep pets and children clear, watch where the snake goes, and call a licensed reptile catcher. If anyone is bitten, treat it as a life-threatening emergency.
Eastern Brown Snake
The Eastern Brown Snake is Australia's most medically significant snake. They are dangerously venomous, widespread across Sydney's western and outer suburbs, and capable of killing a person within hours if a bite is untreated. They are not aggressive, but they will defend themselves vigorously when they feel threatened, and they don't always retreat. Juveniles are just as dangerous as adults despite looking quite different.
The right response is non-negotiable: stop, back away, keep pets and children clear, watch where the snake goes, and call a licensed reptile catcher. Don't try to handle, kill or interact with the snake. If anyone is bitten, treat it as a life-threatening emergency.