No. The rule “round pupils mean harmless, slit pupils mean venomous” fails for Australian snakes. Pupil shape is a feature used in descriptions of species, but it is not a reliable way to decide whether an unfamiliar snake is venomous.
A venomous snake with round pupils
The inland taipan has round pupils. It is also highly venomous. That single example is enough to show why a round eye cannot establish that a snake is safe to approach.
A small feature in a distant or blurred photograph may be difficult to make out in the first place.
A python with vertical pupils
The green python provides the opposite example. Toronto Zoo describes its vertical pupil, while the Australian Museum’s green python account identifies it as non-venomous. A vertical pupil therefore does not establish that a snake has venom.
“Non-venomous” also does not mean that a wild snake should be handled. The eye-shape shortcut answers neither the species question nor how to interact with the animal.
What does pupil shape relate to?
Comparative research on snakes examines pupil shape alongside hunting behaviour and times of activity. These relationships are more complicated than a two-column list of dangerous and harmless snakes.
Nor should eye shape become a rigid day-versus-night rule. The night activity guide explains why activity varies.
For an existing photograph, use the photo identification guide to consider the location and visible features together. Do not move closer to obtain an eye photograph.
