Besides the visual differences which is not often grasped by the inexperienced public, there is a scalation difference on the head that is quite easy to see once pointed out. The brown snakes of the genus Pseudonaja have a single temporal scale and the black snakes of the genus Pseudechis have two temporal scales.
While the King brown is considered to be a large elapid, size varies accordingly to location but generally speaking they seem to be of a larger size further north with the occasional specimen reaching close to 10 foot in total length.
Although highly venomous I have personally found that they only reluctantly strike when first disturbed but can become pugnacious when provoked and will flatten out their neck and try to bite. One thing worth noting is that their venom output is quite large and this is another factor that makes them highly dangerous.
The King Brown shelters in burrows, logs, rock piles, etc. Prey consists of small mammals, birds, snakes, lizards, and frogs.
King browns are often found active just on dusk and in the hotter parts of the year become nocturnal.
Mating occurs around late spring here in the Pilbara and they lay on average nine eggs.