The king brown snake may be active by day or night, depending on the climate (3) (4), and is known to feed on frogs, birds, small mammals and even other reptiles (2) (3) (4), including lizards (2).
When threatened, the king brown snake tends to flatten its neck, spreading it into a hood-like shape, before raising its body into an arch and striking rapidly (2) (3). The venom produced by this species is extremely toxic, causing lightheadedness, headaches, nausea, vomiting, muscle weakness and mild paralysis in humans (9) (10).
Until relatively recently, it was thought that all large Pseudechis species were live-bearing snakes, but most, including the king brown snake, have since been found to be oviparous, meaning that they lay eggs (11). The female king brown snake has been recorded to lay between 4 and 19 eggs per clutch (2). While no information is available on incubation periods in the wild, clutches of king brown snake eggs laid in captivity have been known to incubate for between 85 and 88 days at higher temperatures, and for shorter periods at lower temperatures (12).