A dangerously venomous snake with tremendous variation in colour and pattern - some colour morphs are illustrated below. This snake is very abundant in close proximity to human dwellings and is involved in most snakebite deaths in Western Australia (eight of last thirteen WA fatalities attributed to snakes).
Many recognise this snake as Pseudonaja mengdeni - see Adam Skinner (2009): A multivariate morphometric analysis and systematic review of Pseudonaja (Serpentes, Elapidae, Hydrophiinae). Zool. J. Linnean Soc., 2009, 155, 171-197 for a description of P. mengdeni and restriction of P. nuchalis to northern Australia, hence its common name, Northern Brown Snake.
Courtship - both individuals are dark coloured, but it is not unusual to see different coloured morphs mating or fighting.
Neonatal Gwardar - note dark head typical of young brown snakes.